national joint registry for england and wales 4th annual report

National Joint Registry for England and Wales4th Annual Report

National Joint Registrywww.njrcentre.org.uk

ISSN 1753-9382

Prepared by

The NJR Centre, Hemel Hempstead

Peter Drury

Julia Morrison

Claire Newell

Dr Martin Pickford

Martin Royall

Mike Swanson

Lynn May, M&M Communications

Royal College of Surgeons Clinical Effectiveness Unit

Jan van der Meulen

Nokuthaba Sibanda

The Department of Health

The NJR Steering Committee

This document is available in PDF format for download on the NJR website.

www.njrcentre.org.uk

4th Annual Report 03

Contents

Chairman’s Introduction 07

Vice-Chairman’s Introduction 08

Executive Summary 09

Part 1

1. Introduction 12

1.1 Annual Report 13

1.2 The National Joint Registry 13

2. Progress 14

2.1 Challenges 15

2.2 Progress 15

2.3 Key Figures 18

2.4 Developments 22

2.5 NJR Stakeholders, Support and Governance 23

2.6 Information, Communication and Monitoring 24

3. Finance 26

3.1 Income and Expenditure 27

3.2 Changes to the Levy 27

4. Taking The NJR Forward 28

4.1 Improving Data Quality and Completeness 29

4.2 Service Development 29

4.3 The Future 29

4.4 NJR Steering Committee 29

Appendices

Appendix 1 NJR Steering Committee 2006/07 31

Appendix 2 NJR Steering Committee Terms of Reference 34

Appendix 3 Regional Clinical Coordinators 35

Appendix 4 Regional Clinical Coordinators Network Terms of Reference 36

Appendix 5 NJR Services to Stakeholders 37

Appendix 6 NJR Units Not Returning Data in 2006/07 38

Appendix 7 Supporting Data for Figures 39

Appendix 8 Locations of Audit and Training Meetings 41

Tables

Table 1 Provider: distribution of operations by type (hip or knee) and provider organisation, NJR records, 2004/05 to 2006/07

Figures

Figure 1 NJR Compliance: 2003 – 2007, based on levies from implant sales

Figure 2 NJR Consent: quarterly analysis of total records received and those with patient consent, 2003/04 – 2006/07

Figure 3 NJR Linkability: analysis of total records received and those for which NHS numbers have been traced, 2003/04 – 2006/07

Figure 4 Total: hip and knee joint replacement operations entered on the NJR, 2003/04 to 2006/07, recorded by country in which theoperation took place

Figure 5 Type: hip and knee joint replacement operations entered on the NJR, 2003/04 to 2006/07, recorded by type of operation

Figure 6 Provider: distribution of hip and knee replacement operations by provider organisation, NJR records, for the threeyears 2004/05 to 2006/07

04 National Joint Registry

Part 2

1. Introduction 42

2. Compliance and Linkage to the Hospital Episode Statistics Database 44

2.1 Compliance for Procedures Undertaken in 2006 45

2.2 Linkage of NJR Procedures to HES Episodes 45

3. Overview of Hip and Knee Replacement Procedures, 2006 52

3.1 Hospitals and Treatment Centres Participating in the NJR 53

3.2 Hip Replacement Procedures 53

3.3 Knee Replacement Procedures 53

4. Hip Replacement Procedures 60

4.1 Hip Replacement Procedures, 2006 61

4.2 Outcomes Following Primary Hip Replacement, 2003 – 2006 64

5. Knee Replacement Procedures 88

5.1 Knee Replacement Procedures, 2006 89

5.2 Outcomes Following Primary Knee Replacements, 2003 – 2006 90

6. Prostheses Used in Hip and Knee Replacement Procedures 108

6.1 Prostheses Used in Hip Procedures 109

6.2 Prostheses Used in Knee Procedures 110

6.3 Cement Use 111

6.4 Bone Substitute Use 111

Appendices

Appendix 1 Assessment Criteria for Total Hip Prostheses Utilised by the Orthopaedic Data Evaluation Panel (ODEP) 128

Tables

Table 2.1 Hip or knee joint replacement procedures carried out in England between 1 April 2003 and 30 September 2006 that were linked to a HES episode, by provider type

Table 2.2 Comparison of patient, procedure and provider type for HES-linked and non HES-linked hip replacement procedures, 1 April 2003 to 30 September 2006

Table 2.3 Comparison of patient, procedure and provider type for HES-linked and non HES-linked knee replacementprocedures, 1 April 2003 to 30 September 2006

Table 3.1 Total number of hospitals and Treatment Centres in England and Wales able to participate in the NJR andproportion actually participating in 2006

Table 3.2 Number of participating hospitals according to number of procedures entered over the 2006 data collection period

Table 3.3 Patient characteristics and procedure details according to type of provider for hip procedures in 2006

Table 3.4 Patient characteristics and procedure details according to type of provider for knee procedures in 2006

Table 4.1 Patient characteristics for primary hip replacement procedures in 2006, according to type of procedure

Table 4.2 Age and gender for primary hip replacements in 2006

Table 4.3 Characteristics of surgical practice for primary hip replacement procedures in 2006, according to type of procedure

Table 4.4 Thromboprophylaxis regime for primary hip replacement patients prescribed at time of operation, according to procedure

Table 4.5 Reported untoward intra-operative events for primary hip replacement patients in 2006 according to procedure type

Table 4.6 Patient characteristics for hip revision procedures in 2006, according to procedure type

Table 4.7 Indication for surgery for hip revision procedures in 2004 to 2006


Table 4.8 Components removed during hip revision procedures in 2006

Table 4.9 Components used during single stage hip revision procedures in 2006

Table 4.10 Types of hip re-operation other than revisions in 2006

Table 4.11 Characteristics of patients undergoing hip re-operations other than revision

Table 4.12 Revision at 1 year for primary hip replacement procedures undertaken between 1 April 2003 and 30 September2006 that were linked to a HES episode

Table 4.13 Causes of failure for primary hip replacement implants undertaken between 1 April 2003 and 30 September 2006that were linked to a HES episode and had a revision also linked to a HES episode

Table 4.14 Mortality rates and age-and-gender-standardised mortality ratios at 1 year following primary hip replacement forprocedures linked to a HES `episode, 2003-2005

Table 4.15 Mortality at 1 year for primary hip replacement procedures undertaken between 1 April 2003 and 30 June 2006 thatwere linked to a HES episode

Table 4.16 Length of hospital stay following admission for a primary hip replacement for procedures linked to a HES episode2003 – 2006

Table 4.17 Length of hospital stay following admission for a primary hip procedure according to age and gender forprocedures linked to a HES episode, 2003 – 2006

Table 5.1 Patient characteristics for primary knee replacement procedures in 2006, according to type of procedure

Table 5.2 Age and gender for primary knee replacements in 2006

Table 5.3 Characteristics of surgical practice for primary knee replacement procedures in 2006, according to type of procedure

Table 5.4 Thromboprophylaxis regime for primary knee replacement patients prescribed at time of operation, according to procedure

Table 5.5 Reported untoward intra-operative events for primary knee replacement patients in 2006 according to procedure type

Table 5.6 Patient characteristics for knee revision procedures in 2006, according to procedure type

Table 5.7 Combinations of implants removed during Single and 2-Stage Knee Revision procedures in 2006

Table 5.8 Types of knee re-operations entered into the NJR database

Table 5.9 Characteristics of patients undergoing knee re-operations other than revision

Table 5.10 Revision at 1 year for primary knee replacement procedures undertaken between 1 April 2003 and 30 September2006 that were linked to a HES episode

Table 5.11 Causes of failure for primary knee replacement implants undertaken between 1 April 2003 and 30 September 2006that were linked to a HES episode and had a revision also linked to a HES episode

Table 5.12 Mortality rates and age-and-gender-standardised mortality ratios at 1 year following primary knee replacement forprocedures linked to a HES episode, 2003-2005

Table 5.13 Mortality at 1 year for primary knee replacement procedures undertaken between 1 April 2003 and 30 June 2006that were linked to a HES episode

Table 5.14 Length of hospital stay (days) following admission for a primary knee replacement for procedures linked to a HESepisode, 2003 - 2006

Table 6.1 Frequency of material chosen for femoral heads in procedures performed in 2006

Table 6.2 Frequency of femoral head sizes for procedures performed in 2006

Table 6.3 Tibial insert type 2006

Table 6.4 Type of cement used in hip and knee replacement procedure cement entered into the NJR in 2006

Table 6.5 Cemented cup brands entered during 2006 for hip replacements

Table 6.6 Cementless cup brands entered during 2006 for hip replacements

Table 6.7 Cemented stem brands entered during 2006 for hip replacements

Table 6.8 Cementless stem brands entered during 2006 for hip replacements

Table 6.9 Brands of resurfacing heads entered into the NJR in 2006

Table 6.10 Procedures using a resurfacing cup with a conventional stem in 2006

Table 6.11 Top 20 Cup - Stem combinations recorded in the NJR in 2006

Table 6.12 Total Condylar knee brands entered into the NJR in 2006 for total knee replacements and hybrid and revision procedures


Table 6.13 Unicondylar knee brands entered into the NJR in 2006 for unicondylar knee procedures

Table 6.14 Patello-femoral joint brands entered into the NJR in 2006 for patello-femoral joint replacement procedures

Table 6.15 Fixed and rotating hinged knee brands 2006

Table 6.16 Brands of antibiotic bone cement entered into the NJR in 2006

Table 6.17 Brands of non-antibiotic bone cement entered into the NJR in 2006

Table 6.18 Brands of synthetic bone substitute entered into the NJR in 2006

Figures

Figure 2.1 Flow chart illustrating linkage of the NJR with HES

Figure 3.1 Number of participating hospitals by number of procedures, 2004 - 2006

Figure 3.2 Primary hip procedures by provider type

Figure 3.3 Primary knee procedures by provider type

Figure 4.1 Type of primary hip replacement procedure undertaken between 2004 and 2006

Figure 4.2 Age and gender for primary hip replacement patients in 2006

Figure 4.3 Revision rate estimates for HES-linked primary hip replacement procedures, 2003 - 2006

Figure 4.4 Revision rate estimates by age for HES-linked primary hip replacement procedures, 2003 - 2006

Figure 4.5 Revision rate estimates for male and female patients with HES-linked primary hip replacement procedures

Figure 4.6 Revision rate estimates for the five most commonly used hip cemented stem brands, 2003 - 2006

Figure 4.7 Revision rate estimates for the three most commonly used hip cementless stem brands, 2003 - 2006

Figure 4.8 Revision rate estimates for the five most commonly used hip cemented cup brands, 2003 - 2006

Figure 4.9 Revision rate estimates for the three most commonly used hip cementless cup brands, 2003 - 2006

Figure 4.10 Revision rate estimates for the most commonly used brand of hip resurfacing prostheses, 2003 - 2006

Figure 4.11 Mortality for patients with and those without any thromboprophylaxis prescribed at the time of primary hipreplacement, 2003 - 2006

Figure 5.1 Revision rate estimates for HES-linked primary knee replacement procedures, 2003 - 2006

Figure 5.2 Revision rate estimates by age for HES-linked primary knee replacement procedures, 2003 - 2006

Figure 5.3 Survival to revision and revision rates for male and female patients with HES-linked primary knee replacementprocedures, 2003 - 2006

Figure 5.4 Revision rate estimates for the five most commonly used brands of total condylar knee prostheses, 2003 - 2006

Figure 5.5 Revision rate estimates for the most commonly used brand of unicondylar knee prostheses, 2003 - 2006

Figure 5.6 Revision rates comparing use and non-use of minimally invasive surgery in unicondylar knee procedures, 2003 - 2006

Figure 5.7 Mortality for patients with and those without any thromboprophylaxis prescribed at the time of primary kneereplacement, 2003 - 2006

Glossary 130


Chairman’s Introduction

Bill Darling C.B.E. D.L. F.R.Pharm.S.

It is my pleasure, as Chairman of the National Joint RegistrySteering Committee, to introduce our 4th Annual Report. It covers the period from April 2006 to March 2007 with areport on the analysis of data on hip and knee jointreplacement operations held on the National Joint Registryin Part 2. I believe this Annual Report will prove to be ofgreater value to all stakeholders than its three predecessors.As the NJR data base continues to expand the quality, typeand value of analysis now available from the NJR hasincreased significantly.

We have made solid progress in a number of areas. Inparticular NJR Reports Online went live in October 2006tailored to the specific needs of surgeons and hospital datamanagers providing access to data in the form of pre-builtreports with reports for hospital management planned for the near future. During the year the NJR Information Bureauresponded to a large number of requests for information,providing accessibility to data whilst at all times protectingpatient and clinician confidentiality.

Work on improving patient consent and compliance continueswith our targets for June 2008 remaining at 90% and 95%respectively. The number of records now in the registry isclose to 450,000. We have seen an increase in the level ofpatient consent and work is underway to help units produceforms which will allow consent to be obtained at the sametime as permission to operate.

The key issue of Linkability has been moved to the top of the agenda. Work is ongoing to link the NJR data to thatheld in the Hospital Episode Statistics (HES) and the PatientEpisode Database for Wales (PEDW) which will facilitate amore detailed analysis of the data, in particular relating torevisions and outcomes. This is demonstrated in Part 2 ofthe Report which looks at NJR and HES linked data,increasing the ability to link revision operations to primaryhip and knee joint replacement operations for patients onthe NJR database. This will significantly assist survivorshipanalysis and will be a priority for the year 2007/08.

During the year a number of hospitals began to use the NJRdata for clinical audit and started to review practice in theirhospital in comparison with practice nationally and in doingso seeking to improve the patient care they provide. A development which I welcome and which I hope otherswill adopt.

Once again I record my thanks to Professor Paul Gregg whohas given me great support during this year. I would also liketo thank the members of the Steering Committee for theircommitment and hard work to move the database forward. A key component of this progress has been the work of theRegional Clinical Coordinators who have continued to showgreat enthusiasm for the project.

My thanks also go to the NJR Regional Coordinators; I knowthat their practical advice, support and guidance to orthopaedicunits and other stakeholders has been much appreciated.The input of the Department of Health has been significantand in particular I would like to thank Ramila Mistry and KateWortham for all their help and support. Finally I record mythanks to Northgate Information Solutions whose technicalexpertise has enabled us to make so much progress this yearand positioned us to make very real advances during 2007.

Bill DarlingChairman, NJR Steering Committee


Vice-Chairman’s Introduction

As Vice-Chairman of the National Joint Registry SteeringCommittee, I am pleased to introduce Part 2 of the 4thAnnual Report.

Management of the National Joint Registry was awarded to a new Contractor, Northgate Information Solutions, from the1 April 2006. Despite this significant change, we have madesolid progress in a number of areas, as indicated in theChairman’s Introduction to the 4th Annual Report.

Compliance and patient consent continue to improve and I am hopeful that by June 2008 our targets of 95% and 90% respectively will be achieved.

A major new development has been the work to link consentedNJR records to those held in Hospital Episode Statistics (HES).This should improve, dramatically, the ability to link primaryprocedures with subsequent revisions and, in the future,provide the opportunity of measuring other outcomes followingtotal joint replacement surgery. Already, using this methodology,survivorship analyses for various types of total joint replacementprocedures and brands of prostheses have been producedand are published, for the first time, in this Report. Inparticular, survivorship analysis for a significant number of hipresurfacing procedures has been performed and the resultscompared with more conventional hip replacementprocedures. Data on unicondylar knee prostheses, mortalityand its relation to thromboprophylaxis and length of stay arealso presented.

I believe our surgeons should be justly proud of the resultswhich are published in this Section, particularly those relatingto mortality and survivorship.

I know that some believe that progress has been slower thanwished for, but it is a credit to the progress that has been made,that the size of our National Joint Registry now covers almost400 orthopaedic units, and is larger than other NationalRegistries, for example the Swedish and Australian Registries.

I wish to add my sincere thanks to those of Bill Darling,Chairman of the National Joint Registry Steering Committee,to all those who have contributed to the ongoing developmentof the National Joint Registry. In particular, I wish to thank Billfor all his hard work both within and outside the Committeeand, of course, our surgeons for entering their data andhope that they will continue to do so.

Finally, we do wish to encourage the use of NJR data forresearch and audit purposes. Potentially, we now have anextremely large and important database. Anyone wishing topursue this possibility should write to the National JointRegistry Centre, following which they will be advised of theappropriate procedure.

Paul GreggVice-Chairman, NJR Steering Committee


Executive Summary

The National Joint Registry 4th Annual Report is the formalpublic report of the National Joint Registry for the period 1 April 2006 to 31 March 2007. In addition it contains ananalysis of the data held on the Registry.

The National Joint Registry (NJR) was established toimprove care for patients who require hip and knee jointreplacement implants and surgery. It does this by collectingdata that can be used to measure the long-termeffectiveness of implants used in hip and knee jointreplacement surgery and information about the surgicalprocedures involved.

The work programme of the NJR Centre in England andWales is set and overseen by the NJR Steering Committee,working with the Department of Health as an advisory non-departmental public body.

Part 1

Part 1 of this document reports on the performance anddevelopments of the Registry during the financial year 2006/07.It provides an account of the work, composition and fundingof the NJR Steering Committee and indicates key areas forfuture development.

Key achievements and developments during the year2006/07 included:

• recording 131,378 hip and knee joint replacementoperations, which represented 81%1 of such operationsundertaken in NHS and independent healthcare units inEngland and Wales and brought the total recorded on theRegistry to 433,319 by 31 March 2007

• publishing a detailed analysis of data collected by the Registry

• increasing the number of records with patient consent to personal information being included on the Registry,from 78% in the final quarter of 2005/06 to 83% by end of 2006/07

• increasing the number of records with both patientconsent and the patient’s NHS number, from 58% (as shown in NJR 3rd Annual Report) to 69%.

Data capture has been improved by:

• increasing direct, on-site support for individual hospitalsand treatment centres to help them set up or improveprocesses for submitting information

• introducing close monitoring of all units to identify thosewhich may require support in improving compliance withNJR requirements

• gaining retrospective exemption from the Health andSocial Care Act 2001, Section 60, which restricted use ofthe personal details of patients for whom a response of‘don’t know’ had been allocated in the records

• patients being asked for consent to provide their personaldetails to the NJR at the same time as giving their consentto undergo surgery.

Information held on the Registry has been made more accessible by:

• launching NJR ReportsOnline for surgeons and hospitaldata managers, which provides information aboutoperations, case mix and implant usage

• improving NJR StatsOnline

• publishing the NJR Annual Report 2005/06 and 3rdAnnual Clinical Report

• reporting on NJR data and services in its newsletter Joint Approach

• producing a starter pack of information for new unit staff.

Additional developments include:

• devising a new, shorter, easier to use dataset forintroduction in 2007/08, subject to formal approval

• progressing links with Hospital Episode Statistics (HES)patient records to make more data available for analysisfor operations carried out on NHS patients in England

• holding and attending a range of events for stakeholders

• during 2007/08 the patient record linkage will be extendedto NHS patients treated in Wales using Patient EpisodesDatabase Wales (PEDW)

• a planned extension to the NJR to cover Northern Ireland.

1 Number of operations recorded on NJR relative to sales of implantsbetween 1 April 2006 and 31 March 2007


Part 2

Part 2 of the NJR 4th Annual Report summarises the data forhip and knee procedures carried out between 1 January to31 December 2006 in England and Wales and entered intothe NJR by 28 February 2007. It also includes a description ofoutcomes after hip and knee replacement, based onprocedures entered into the NJR since the start of datacollection in April 2003 that were linked to records in theHospital Episode Statistics database.

NJR compliance in 2006

• The total number of levies collected between 1 Januaryand 31 December 2006 was 154,066 and the total numberof hip or knee replacement procedures reported to the NJRwas 122,442 (116,046 in England and 6,396 in Wales).This suggests that the compliance rate was 79% forprocedures carried out during the 2006 calendar year inthe NHS and the independent sector, which is animprovement compared with 77% in 2005 and 60% in 2004.

Overview of hip and knee procedures carried out in 2006

• In 2006, 4152 NHS and independent sector hospitals and treatment centres (392 in England and 23 in Wales)were open and 393 (95%) submitted data to the NJR. Onaverage, 112 hip replacements and 99 knee replacementswere recorded per participating healthcare unit.

• The NJR recorded 61,456 hip replacement procedures, ofwhich 10% were revisions or re-operations, and 60,986knee replacement procedures, of which 8% were revisionsor re-operations undertaken between 1 January and 31 December 2006.

• Of the hip procedures, 65% were carried out in NHShospitals, 25% in independent hospitals, 5% in NHStreatment centres and 4% in independent sector treatmentcentres. Corresponding percentages for knee procedureswere 67% in NHS hospitals, 21% in independenthospitals, 7% in NHS treatment centres and 5% inindependent sector treatment centres.

• There was an increase in patients with mild orincapacitating disease prior to surgery in primary hip andknee replacement procedures. The percentage of patientswith mild disease or more severe comorbidity increasedgradually from 68% in 2004 to 76% in 2006 in patientsundergoing primary hip replacement, and from 74% in2004 to 82% in 2006 in patients undergoing primary knee replacement.

• There has been a trend towards more cementless total hipreplacement procedures and fewer cemented proceduressince 2004. Cementless hip replacements increasedgradually from 21% in 2004 to 30% in 2006 and cementedreplacements declined from 53% in 2004 to 48% in 2006.

• 155 different brands of acetabular cups and 176 differentbrands of femoral stems were recorded, compared with110 cups and 129 stems in 2005 and 88 cups and 101stems in 2004. Of all procedures with the cup and stembrand reported in 2006, 22% used ‘mixed and matched’ cup-stem combinations.

• The relative frequencies of the different knee proceduretypes have largely remained unchanged since 2004.

• 54 brands of total condylar knee prostheses wererecorded. In addition, there were 13 brands of unicondylarprostheses, 7 brands of patello-femoral replacementprostheses and 12 brands of hinged prostheses. The number of brands for each prosthesis type remainedmore or less the same compared with 2005. However,there was an increase of about 50% compared with 2004in the number of brands used for knee replacement.

Outcome of hip and knee procedures carried out between 1 April 2003 and 30 September 2006

• Revision rates, mortality and length of stay were analysedusing data obtained from linkage of the NJR to theHospital Episode Statistics (HES) database, with specialattention given to hip resurfacing and unicondylar kneereplacement. The HES database records proceduresundertaken in England and includes only patients treatedin NHS hospitals, in NHS treatment centres, and thosetreated in independent hospitals and independent sectortreatment centres with NHS funding.

• When interpreting the revision rates, one should take intoaccount that not all revision procedures that occurred mayhave been identified through the linkage process.Furthermore, when comparing revision rates with othernational registries, one should take into account that theremay be differences in the definition of a revision and thatre-operations may have been included by some registries.

• Of all 355,480 hip or knee replacement proceduresrecorded in HES and carried out between April 2003 andSeptember 2006 at NHS hospitals and NHS treatmentcentres, or in the independent sector and funded by theNHS, 187,220 (53%) could be linked to the NJR. Linkagewas not possible for procedures that were not recorded in the NJR (non-compliance) or for those recordedprocedures for which patient identifiers were not available.

2 These are the figures for the calendar year, 1 January 2006 to 31 December 2006 and will vary from figures quoted for the financialyear 1 April 2006 to 31 March 2007 elsewhere in the Report


• The number of procedures that could be linked differedbetween provider types. About 70% of hip or kneereplacement procedures undertaken at NHS hospitals orNHS treatment centres could be linked, compared with onlyabout a quarter of those carried out at independent sectortreatment centres, and less than 10% of those carried outin independent hospitals. Therefore, the HES-linkedprocedures are most representative of proceduresundertaken at NHS hospitals and NHS treatment centresin England.

• The overall revision rate for primary hip replacement was 0.7% (95% CI3: 0.6% to 0.7%) at 1 year and 1.3% (95% CI: 1.2% to 1.5%) at 3 years. Procedure type wasfound to be the most influential factor on implant survivalfollowing primary hip replacement. 1 year revision ratesafter hip resurfacing (1.6%, 95% CI: 1.3% to 2.0%) werefive times higher than cemented total hip replacement(0.3%, 95% CI: 0.3% to 0.4%). After adjusting for patientage, gender, general medical condition and provider type,hip resurfacing procedures were found to still have astatistically significantly higher revision rate (hazard ratio4.6, 95% CI 3.4 to 6.2) within 1 year compared withcemented total hip replacement. There was evidence thata large number of the failures of hip resurfacing prostheseswere in older female patients, indicating the need forcareful patient choice. Analysis of longer term survival is necessary to establish the comparative long termperformance of hip resurfacing.

• The overall revision rate for primary knee replacement was 0.4% (95% CI 0.3% to 0.4%) at 1 year and 1.4% (95% CI: 1.2% to 1.6%) at 3 years. Revision rates at 1 year were similar between cemented total knee andunicondylar knee primary replacements. 0.3% of cementedknee replacements needed revision within 1 year,compared with 0.4% of unicondylar knee replacements.

• Mortality at 1 year was 1.9% after hip replacement and1.6% after knee replacement, which is less than half ofthat observed in the age-matched and sex-matchedgeneral population in England and Wales. Thesedifferences demonstrate that patients who undergo hip orknee joint replacement are a highly select group.

• A thromboprophylaxis regime was prescribed for 74,868(98%) of primary hip replacement patients and 76,581(98%) of primary knee replacement patients. There was no difference in mortality up to 1 year following primaryhip or knee replacement between patients for whomthromboprophylaxis was prescribed and patients forwhom none was prescribed.

• The average length of hospital stay after a primary hipreplacement was 9.1 days. The shortest length of hospitalstay was found in patients undergoing hip resurfacing,with an average stay of 6.3 days. Following primary kneereplacement, patients stayed on average 8.1 days inhospital. After unicondylar knee replacement, length ofstay was only 5.9 days.

• In this Report it was possible to present analyses of short-term outcomes only up to 3 years following primaryhip or knee replacement on account of length of follow-upthat the NJR allows at the present time. Analysis of longerterm outcomes are necessary to establish whether theresults seen persist. Furthermore, the analyses were basedon data obtained from the linkage of NJR with HES, anexercise that was undertaken for the first time in thisReport and in which linkage was not possible for allrecorded procedures. The results presented should beinterpreted with these factors in mind.

3 CI: Confidence Interval (Statistical Term)

Part 11. Introduction



1.1 Annual Report

This is the fourth annual report of the National Joint Registry(NJR), which provides information about hip and kneereplacement operations in England and Wales within boththe NHS and independent healthcare sector. This informationis valuable to surgeons, patients, members of the public andthe manufacturers of hip and knee implants (artificial joints).NJR collects information that can be used to help improve careand treatment through information on surgical practice and onthe hip and knee implants used in joint replacement surgery.

The Report has been divided into two sections for ease ofreference - a general outline of the work on the NJR and ananalysis of the operations recorded by the Registry.

• Part 1 – a review of progress made on the NJR during thefinancial year 1 April 2006 to 31 March 2007 and its plansto increase still further the value of its information in thefuture.

• Part 2 – an analysis of the data recorded in the calendaryear 1 January and 31 December 2006 and, usinginformation recorded on NJR since April 2003, it focuseson: linked primary and revision operations; hipresurfacing; unicondylar knee replacement and mortalityrates.

1.2 The National Joint Registry

The NJR was set up in October 2002 and began collectingdata on hip and knee replacement operations in April 2003.

The NJR was set up to improve patient care by finding outmore about hip and knee joint replacement implants andsurgery. It is doing this by building up a database ofinformation. The aim is for the Registry to be able to provideinformation for patients, surgeons, hospitals, manufacturersand healthcare regulatory agencies on implant performance,joint replacement surgery and best surgical practice.

The NJR can only achieve its aims if it has a timely andcontinuous supply of high quality information about theoperations that are carried out. This information makes itpossible to monitor the performance and long-termeffectiveness of hip and knee replacement surgery and the implants, known as prostheses, used. The informationon NJR is made available to surgeons, patients, the publicand the manufacturers of replacement joints to help improve care and treatment in the future.

Data is provided to the NJR by NHS and independenthealthcare providers throughout England and Wales. By 31 March 2007 it had received 433,319 records.

The quality of the information received is very important tothe NJR as it affects the level of detail the NJR is able to giveto those who are interested in its findings (a list of stakeholderscan be found in Section 2.5). To support the collection anduse of data, it is important that data collection and entry into NJR is made as easy as possible and that informationheld on NJR is available when required (see Section 2.4 fordevelopments in these areas).

1.2.1 Management and funding

The NJR has been managed by Northgate InformationSolutions (UK) Ltd since April 2006, under a contract withthe Department of Health, and is funded through a levyraised on the sale of hip and knee replacement implants(further information regarding funding is available in Section 5 Part 2).

The NJR’s Steering Committee (NJRSC), which was set upin October 2002, is an advisory non-departmental publicbody. A list of NJRSC members and members’ declarationsof interest is contained in Appendix 1 with the Terms ofReference detailed in Appendix 2. Further information aboutthe NJRSC’s work during 2006/07 is featured in Section 2.5.

Part 12. Progress



2.1 Challenges

The success of the NJR is reliant on meeting three mainchallenges: improving the completeness and quality of theinformation held on the Registry; reducing the burden ofdata entry on hospitals and units supplying the informationand making information held on NJR available for betterpatient care.

The continuing challenges on data completeness and qualityare to ensure:

• all hip and knee joint replacement operations carried outin England and Wales are recorded on the NJR

• the recorded information is of good quality

• patient consent is given for data to be stored and used toachieve the aims of the NJR.

Over the last four years the level at which these datachallenges have been met has increased significantly (see point 2.2). During 2006/07 the NJR Centre improved the way in which on-site support to individual NHS andindependent healthcare hospitals and treatment centres(known as units) is managed and prioritised. (Examples of these improvements are detailed at Section 2.5 under the heading, Regional Coordinators).

There are three ways of measuring these areas of dataquality and completeness:

• compliance – the percentage of records submitted to theNJR compared with the total number of hip and kneereplacement operations carried out in England and Wales,also referred to as ‘case ascertainment’ – target 95% byJune 2008

• consent – the percentage of records submitted to the NJRwith consent given by patients for use of their personalinformation4 – target 90% by June 2008

• linkability – the percentage of records that have patientconsent and the patient’s NHS number so that alloperations performed on the same patient can be linked.The goals of the NJR will only be achieved if operationson the same patient can be successfully linked – target90% by June 2008.

In addition to addressing these targets, the NJR Centre’swork during 2006/07 centred on:

• making it easier for records to be submitted

• sharing best practice through workshops for staff involvedin the administration of NJR in NHS and independenthealthcare units and encouraging them to share ideas.Regional Coordinators have also been active in sharinginformation about the most effective processes during theirvisits to units where submission of data to NJR is poor

• making information more easily accessible to surgeons,staff in units using the NJR and hospital management.NJR ReportsOnline has been implemented, giving local,summary information about the NJR, for example, casemix and implant usage for surgeons. Reports have beendesigned for hospital managers and will be implementedin 2007/08

• improving performance monitoring.

These initiatives, which are designed to help ensure that thecommitment of stakeholders to NJR is maintained, will beprogressed further during the year ahead. More work will beundertaken to improve still further the information availableto stakeholders, for example, through the links beingdeveloped with other NHS systems.

2.2 Progress

Progress on these challenges during 2006/07 is consideredacross the different areas.

2.2.1 Data completeness and quality complianceAll NHS and independent healthcare units in England andWales are asked to submit details of their hip and kneereplacement operations. The method used to monitorcompliance with this request is to compare the number oflevies raised from the sale of implants to the number ofsubmissions from units.

Figure 1(overleaf) illustrates the compliance rate (caseascertainment) across all units over the last four years.Compliance increased significantly over the first three yearsof the NJR. In 2003/04, from 156,354 operations5 which tookplace, 62,191 operations were recorded on the NJR giving acompliance rate of approximately 40%, but by 2005/06, therate had risen to 82%, 132,578 of 161,000 operations. The rate decreased slightly during 2006/07 to 81.3%, 131,378of just under 158,000 operations against an apparentdecrease in the number of operations performed in Englandand Wales based on the levies collected from implants sold.

Of the 4206 units expected to submit data to the NJR 11failed to submit any records during 2006/07. These are listedin Appendix 6.

4 Personal information includes NHS number, surname, date of birth and postcode

5 Operations – this is an estimate of the number of hip and knee jointreplacement operations performed in England and Wales based on the number of levies collected on implants sold

6 This is for the financial year from 1 April 2006 to 31 March 2007


2.2.2 ConsentWhy is it important for patients to give consent?

By consenting to the inclusion of their personal details onthe NJR database, patients enable more accurate study ofthe outcomes of hip and knee replacement operations. Inturn, this means the NJR is able to provide information thatcan be used to:

• improve awareness of the outcomes of replacement surgery

• help patients obtain the best clinical care for jointreplacement surgery

• look at the performance of implants and help identify anybrand of implant showing high failure rates

• improve surgical practice including information that canbe used to identify best surgical practice

• help NHS and other healthcare organisations to makebest use of their resources.

Patients must give consent for their personal details to beused on the NJR database and once they understand thepurpose of the NJR, they rarely refuse to give consent when asked.

Recording a patient’s personal details, including their NHSnumber, enables the linking of operations for that patient thathave either been carried out already or may be carried out inthe future. This will enable problems either with implants orsurgical techniques to be identified at an early stage and the

appropriate action taken. This information on NJR will alsoenable hospitals to be identified and assisted when theyneed to recall patients who have received an implant that issuspected of failing to perform as expected.

The rates of patient consent are published monthly on theNJR website in NJR StatsOnline (www.njrcentre.org.uk). The percentage of records submitted to the NJR with thenecessary consent rose from 78% (29,238 of 37,416 NJRrecords) in 2005/06 Quarter 4 (1 January to 31 March 2006),to 83% (30,746 of 36,862 NJR records) in 2006/07 Quarter 4(1 January to 31 March 2007).

Figure 2 (right) shows the pattern of patient consent over thelast four years.

A consent rate of approximately 64%, 39,433 from 61,781recorded operations was reported in the NJR’s first year; thisdipped to below 60%,16,273 of 27,249 recorded operationsduring the second quarter of 2004/05 but it has risen virtuallyevery quarter since then. Further improvement is needed inorder to achieve the target of 90% by June 2008.

At present, when submitting records, participating units maychoose from three options for patient consent: ‘yes’, ‘no’and ‘don’t know’. During 2006/07, of 131,378 recordssubmitted to the NJR, 6% (7,680) included a ‘no’ responseand 13% (16,551) ‘don’t know’.

It is likely that many of the ‘don’t know’ and ‘no’ responsesarise because either the patient has not been asked forconsent or the completed consent form was not available atthe time of entering the record.

2003/04 2004/05

Year

NJR

Rec

ords

Con

sent

Rat

e (%

)

2005/06 2006/07

180,000 –

160,000 –

140,000 –

120,000 –

100,000 –

80,000 –

60,000 –

40,000 –

20,000 –

0 –

– 90%

– 80%

– 70%

– 60%

– 50%

– 40%

– 30%

– 20%

– 10%

– 0 %

Number of NJR Operations

Levy

Compliance

Figure 1NJR Compliance: 2003 – 2007,based on levies from implant sales

Source: Operations entered on NJR1 April 2003 – 31 March 2007 andlevy submissions to NJR by implantsuppliers and manufacturers. For supporting data see Appendix 7


2.2.3 Section 60 exemptionDuring the year in view, the NJR Centre was grantedexemption7 by the Patient Information Advisory Group (PIAG)from some of the requirements of the Health and Social CareAct 2001, Section 60. This means that for all the recordssubmitted to NJR with a ‘don’t know’ response regardingconsent, a patient’s personal details may be recorded for thepurposes of improving linkability of NJR records with otherrecords on the same patient. However, if a patient laterrefuses consent, their personal details will be removed fromthe NJR records. The data entry system was altered on 31 March 2007 to support this change.

The exemption is retrospective, enabling the NJR Centre tobegin to improve the linkability of previous years’ records.

2.2.4 Changes to the consent processThe NJR Centre has been looking at ways to help units withthe patient consent process.

During 2006/07 it was confirmed that NJR consent can besought at the same time as consent to operate, providing itis made clear to patients that receiving treatment is notdependent on giving consent for their data to be stored onthe NJR. This removes the problems associated with havingto seek consent from patients for their personal details to beplaced on the NJR at a different time from their consentto operate.

Work has started on local ‘consent to operate’ forms toenable units to have approved text which they can add totheir own, local ‘consent to operate’ forms.

2.2.5 LinkabilityLinkability enables comparisons to be drawn betweenoperations, for example, by looking at the primary (first) hipor knee joint replacement operation and the subsequentrevisions or re-operations on the same joint in the samepatient. The accuracy of findings from the NJR depends onhaving a sufficiently high number of NJR records containingpatient information that will allow the NJR record to be linkedto another record of the same patient.

In order for records to be linked, patient consent is requiredfor the storage of personal information. Records mustinclude either the patient’s NHS number or their surname,date of birth and postcode, so that the NHS number can betraced through the National Strategic Tracing Service (NSTS).

The percentage of linkable records held on the NJR from2003/04 to 2006/07 is shown in Figure 3. The level hasimproved significantly from 45% (27,807) of the 61,781records submitted in 2003/04 to 60% (79,733) of 132,191records two years later in 2005/06 and 69% (90,502) of130,927 records submitted in 2006/07. Further work will beneeded to reach the target of 90% by June 2008. Plansinclude use of mandatory information on the data collectionform and using other NHS databases (HES and PEDW) tohelp find the NHS number.

2003/04 2004/05 2005/06 2006/07

Num

ber

of o

pera

tions

on

NJR

and

num

ber

with

con

sent

Con

sent

Rat

e (%

)

40,000 –

35,000 –

30,000 –

25,000 –

20,000 –

15,000 –

10,000 –

5,000 –

0 –

– 90%

– 80%

– 70%

– 60%

– 50%

– 40%

– 30%

– 20%

– 10%

– 0 %

Number of Operations

Number of Consent

Consent RateQ1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4

Figure 2NJR Consent: quarterly analysis of total records received and those with patientconsent, 2003/04 – 2006/07

Source: Operations entered on NJR1 April 2003 – 31 March 2007.For supporting data see Appendix 7

7 This is an annual exemption and has to be re-applied for each year


2.3 Key Figures

2.3.1 On the recordNJR records include the following information about eachoperation:

• patient details (if patient consent is recorded)

• hospital

• surgeon

• operation

• surgical approach

• any untoward event which may have occurred during the operation.

2.3.2 Operation totalsSince the launch of the NJR in April 2003, a total of 433,319hip and knee joint replacement operations in England andWales has been recorded on the NJR. During the first year,2003/04, the number of operations reported was 62,189;with this rising to 107,172 in 2004/05 and 132,577 in 2005/06.

However, in 2006/07, the figure for the year dropped slightly, to 131,378, which is 1,199 (0.9%) fewer than the previous year. This represents a minor decrease incompliance (fewer operations recorded on NJR). See Appendix 7 for supporting data.

Figure 4 (right) shows the total number of operations recordedon NJR in England and Wales each year from 2003/04 to2006/07. It shows that the figures for Wales have increasedeach year and that, in 2006/07, for the first time, the numberof knee joint replacement operations was greater than thenumber of hip joint replacement operations in both countries.In England, during 2006/07, 61,940 knee operations and61,849 hip operations were recorded on the NJR; whilst inWales, the figures were 3,683 for hip operations and 3,906for knee operations.

2003/04 2004/05

Year

Num

ber

of r

ecor

ds s

ubm

itted

and

with

N

HS

num

ber

afte

r N

STS

sea

rch

2005/06 2006/07

140,000 –

120,000 –

100,000 –

80,000 –

60,000 –

40,000 –

20,000 –

0 –

– 80%

– 70%

– 60%

– 50%

– 40%

– 30%

– 20%

– 10%

– 0 %Number of Operations

Number with NHS Number

LinkageRate

Figure 3NJR Linkability: analysis of totalrecords received and those forwhich NHS numbers have beentraced, 2003/04 – 2006/07

Source: Operations entered on NJR1 April 2003 – 31 March 2007.For supporting data see Appendix 7


2003/04

32,221

826

28,450

692

2004/05

53,513

1,605

50,606

1,448

England Hip

Wales Hip

England Knee

Wales Knee

Num

ber

of O

pera

tions

Operations by year and country

2005/06

63,595

2,990

62,959

3,033

2006/07

61,849

3,683

61,940

3,906

70,000 –

60,000 –

50,000 –

40,000 –

30,000 –

20,000 –

10,000 –

0 –

England Hip

Wales Hip

England Knee

Wales Knee

Figure 4Total: hip and knee jointreplacement operations entered onthe NJR, 2003/04 to 2006/07,recorded by country in which theoperation took place

Source: Operations entered on NJR1 April 2003 – 31 March 2007

2.3.3 Total operations:• 2003/04 – 62,191

• 2004/05 – 107,172

• 2005/06 – 132,578

• 2006/07 – 131,378.

2.3.4 Operation typesHip and knee joint replacement operations take three forms:

• primary – the first time a joint is replaced

• revision – an operation that involves the removal and replacement of one or more components of a joint replacement

• re-operation other than revision - an operation followingeither a primary or revision operation that does not requireany joint implants to be removed or replaced, for example,if an implant needs to be re-aligned or has become loose.

The greatest number of operations is of the primary kind. In 2006/07, for example, 121,102 (92%) of the 131,378operations recorded were primary operations; only 9,592(7%) were revisions and 684 (0.5%) re-operations.

During the NJR’s first two years, the number of primary hipjoint replacement operations that were recorded outnumberedthe number of primary knee joint replacement operationsrecorded; however, that trend was reversed in both 2005/06and 2006/07. In 2005/06 primary knee joint replacementoperations exceeded primary joint replacement hip operationsby more than 2,500 (4.4%) and last year, this figure rose tomore than 3,000 (5.4%).

Figure 5 (overleaf) shows the number of operations by typefrom 2003/04 to 2006/07. (Note, hip and knee joint replacementre-operations where not collected in 2003/04).


2.3.5 Total operations:• 2003/04

• Hip: 33,048• Knee: 29,143

• 2004/05

• Hip: 55,118• Knee: 52,054

• 2005/06

• Hip: 66,585• Knee: 65,993

• 2006/07

• Hip: 65,532• Knee: 65,846

2.3.6 Where did the operations take place?In total, of the 433,319 operations recorded over the last fouryears, 415,133 (96%) were carried out in England and 18,183(4%) in Wales. During 2006/07, England carried out 123,789(94%) and Wales 7,589 (6%), as shown in Figure 4 (above).

Patients in England may have their hip and knee joint replacementoperations with one of four different types of organisation:

• NHS hospital

• NHS Treatment Centre

• Independent healthcare hospital

• Independent Treatment Centre.

2.3.7 There are no NHS or independent treatment centres in Wales.

To date, most of the 433,319 operations recorded on NJRwere carried out in an NHS hospital: 264,578 (61% of alloperations) in England and 13,905 (3% of all operations) inWales. Independent healthcare hospitals have undertaken119,590 (28%) of the recorded operations in England and4,278 (1%) in Wales.

The number of hip and knee joint replacement operations

2003/04

30,036

27,911

3,012

1,232

n/a

n/a

2004/05

49,687

49,567

5,186

2,302

245

185

Hip Primary

Knee Primary

Revision Hip

Revision Knee

Hip Re-operation

Knee Re-operation

Num

ber

of O

pera

tions

Operations by year and joint/type

2005/06

60,000

62,616

6,237

3,043

348

334

2006/07

58,952

62,150

6,272

3,320

308

376

70,000 –

60,000 –

50,000 –

40,000 –

30,000 –

20,000 –

10,000 –

0 –

Hip Primary

Knee Primary

Revision Hip

Revision Knee

Hip Re-operation

Knee Re-operation

Figure 5Type: hip and knee jointreplacement operationsentered on the NJR, 2003/04to 2006/07, recorded by typeof operation

Source: Operations enteredon NJR 1 April 2003 – 31 March 2007

carried out at treatment centres in England has continued toincrease. NHS treatment centres have carried out 18,287 (4%)of the operations over the last four years, whilst independenthealthcare treatment centres have carried out 12,681 (3%).For supporting data see Appendix 7.

The number of operations carried out in treatment centres hasrisen steadily over the last three years (see Table 1,overleaf). Of the 107,172 recorded operations in 2004/05,3,202 (3%) were at NHS treatment centres and 1,852 (2%) atindependent treatment centres, while of the 131,378recorded in 2006/07, 7,572 (6%) were at NHS treatmentcentres and 6,383 (5%) at independent treatment centres.

During the same period (see Figure 6 below), the proportion ofhip and knee joint replacement operations recorded on NJR inNHS hospitals remained relatively unchanged (69,300 (64%) in2004/05 and 86,979 (66%) in 2006/07) but the proportion inindependent hospitals dropped, from 32,818 (31%) in 2004/05and 39,635 (30%) in 2005/06 to 30,444 (23%) in 2006/07.

The proportion of hip joint replacement operations recordedat NHS hospitals during this period was much the same at39,474 (33%), while knee joint replacements rose slightly from32,199 (32%) to 41,117 (34%). The corresponding decreasein operations at independent hospitals shows a drop from17,703 (17%) hip and 15,115 (14%) knee in 2004/05 to 16,499(13%) hip and 13,945 (11%) knee joint replacement operationsin 2006/07.

Further analysis of the types of organisation in which patientshave hip and knee joint replacement operations is providedin Figure 6 (below) and Table 1 (overleaf).

Figure 6Provider: distribution of hip and knee replacementoperations by provider organisation, NJR records, for thethree years 2004/05 to 2006/07


Independent Hospitals39,63530%

Independent Treatment Centres 4,1143%

NHSTreatment Centres 7,2946%

NHS Hospitals81,53461%

2005/06

2004/05Independent Hospitals30,44423%




Source: Operations entered on NJR 1 April 2004 – 31 March 2007. For supporting data see Appendix 7.

2006/07

Independent Hospitals32,81831%





2.4 Developments

2.4.1 Reducing workload for stakeholdersData entry can be a burden on stretched resources, which iswhy the NJR Centre has developed a number of measuresto reduce the effort involved in capturing and inputting data.These measures should help to increase compliance ratesfurther and improve data quality.

2.4.2 Reviewing the information requestedThe NJR received the records of a high proportion of thetotal number of hip and knee joint replacement operations inEngland and Wales. However, the amount of detail in therecords submitted to NJR was variable.

Units provide information to the NJR using a special on-lineform. During 2006/07 the NJR Centre reviewed responses tothe dataset and found that, unless a question wasmandatory, the requested information was not provided inmany instances.

Following the review the NJR Centre was keen to improvethe dataset in order to:

• obtain all the information vital to the achievement ofNJR goals

• make it simpler for the units to use.

The result is a proposed new, shorter dataset (MDSv3) in whichall questions are mandatory. This proposed dataset has beenapproved by the NJR Steering Committee and, during 2007/08,will be submitted to the Review of Central Returns (ROCR)8

for the approval required before it can be put into practice.

2.4.3 Bulk uploadTo help reduce the burden of entering information intodifferent databases, it is possible for units to collect NJRdata through their own computer system and transfer it asa block of multiple data records, at regular intervals, to theNJR database. This bulk upload facility saves time spentmanually inputting data to the NJR and helps to preservedata quality.

In total 1,014 records were uploaded through bulk uploadduring 2005/06 and 2,555 records in 2006/07. Improvementswill be made in the short term to ensure that it can transfercomponent data with longer term solutions to be explored.

2.4.4 Components databaseThe number of different implant component parts recordedon the NJR exceeds 50,000 and continues to grow. NJR needs up to date information on all implants used inEngland and Wales so that units can record the implantused accurately on the Registry.

Implant suppliers are required to enter details of all newcomponents onto the NJR before any are sold, but this isnot happening routinely.

In addition, a system of barcode scanning enables hospitalstaff automatically to enter implant details onto the NJR,which saves them time and helps to preserve data quality.Some suppliers have made changes to barcode formatswithout informing the NJR, which has reduced the numberof implants with information that can be scanned into NJR.

The NJR Centre has been working closely with suppliersto overcome these problems and will continue to do soin 2007/08.

Table 1Provider: distribution of operations by type (hip or knee) and provider organisation, NJR records, 2004/05 to 2006/07

NHS Hospital

Independent Hospital

NHS Treatment Centre

Independent Treatment Centre

Total

Hip

35,040

17,703

1,548

827

55,118

2004/05

Knee

34,260

15,115

1,654

1,025

52,054

Total

69,300

32,818

3,202

1,852

107,172

Hip

40,600

20,647

3,403

1,935

66,585

2005/06

Knee

40,934

18,988

3,891

2,179

65,992

Total

81,534

39,635

7,294

4,114

132,577

Hip

42,658

16,499

3,425

2,950

65,532

2006/07

Knee

44,321

13,945

4,147

3,433

65,846

Total

86,979

30,444

7,572

6,383

131,378

Number of Operations

Source: Operations entered on NJR 1 April 2004 – 31 March 2007

8 ROCR is charged with minimising the burden of all ongoing and one-offcentral information requirements on the NHS. Only data collections thathave been approved by ROCR are added to the list of authorised centralreturns published on the Internet


2.5 NJR Stakeholders, Support, and Governance

This section outlines the numerous stakeholders who havean interest in the outcomes of the work undertaken by theNJR. It also describes the organisations and individuals whoguide the work of the NJR, ‘champion’ the NJR to hospitalmanagers and clinicians, and who work with hospitals toensure that good quality information is submitted to the NJR.

2.5.1 StakeholdersThe information held on NJR is of interest to numerousindividuals and organisations and the NJR Centre iscommitted to working with these stakeholders in order toprovide them with a valuable information service tailored totheir individual needs.

2.5.2 NJR stakeholders• Patients and patient groups

• Orthopaedic surgeons and professional bodies, includingthe British Orthopaedic Association, British Hip Society,British Association of Surgery of the Knee and RoyalCollege of Surgeons

• Hospital staff, including theatre nurses, data entry staffand hospital management

• Other healthcare professionals – practitioners with aspecial interest in orthopaedics, including nurses,physiotherapists, occupational therapists, GPs andarthroplasty practitioners

• Industry – orthopaedic implant suppliers and manufacturersand the Association of British Healthcare Industries

• NHS management and commissioners – NHS trusts, NHS foundation trusts, primary care trusts, strategichealth authorities, Welsh NHS regions, GPs and practice-based commissioners

• Public health specialists, epidemiologists and other researchers

• Independent healthcare management – the IndependentHealthcare Advisory Service, independent hospitals andindependent treatment centres

• NHS Supply Chain

• Regulatory bodies, including the Medicines andHealthcare Regulatory Agency, Healthcare Commission,National Patient Safety Agency and National Institute forHealth and Clinical Excellence

• Government Ministers, Department of Health and Welsh Assembly

• Other stakeholders such as the Scottish Executive

• NJR Steering Committee members.

2.5.3 PrioritiesDuring 2006/07 the NJR Centre’s work focused on its targetsfor compliance, consent and linkability. Stakeholders withwhom the NJR Centre worked most closely on this initiativewere orthopaedic surgeons, management and staffresponsible for the NJR process and those routinelyrequiring information from NJR.

2.5.4 The NJR Centre is committed tocontinuing this level of engagement which:• supports and encourages units to submit good quality data

• ensures that it fully understands the informationrequirements of these stakeholders and delivers on them wherever possible

• helps key stakeholders to access and use NJRinformation to improve patient care.

In addition, the NJR Centre will be working with a widerrange of stakeholders during 2007/08.

2.5.5 Regional CoordinatorsThe NJR Centre has six Regional Coordinators (RCs), eachproviding direct, on-site support to approximately 70 units.

The RCs provide a critical link between NJR users and theNJR Centre. Their two-way communications role involvesfeeding back information about stakeholder requirementsand issues while passing on to the units information aboutNJR developments.

2.5.6 RC duties include:• helping units to set up or improve processes for

submitting information

• providing training to unit staff to ensure they can access information

• helping units to make best use of NJR information bypublicising all new aspects of the system including NJRStatsOnline and NJR ReportsOnline and encouragingthem to use the Information Bureau provided by the NJR Centre

• sharing best practice among units

• monitoring unit performance

• helping units to improve their performance where this isas a result of poor compliance and consent rates.

On-site support by the RCs to individual NHS and independenthealthcare hospitals and treatment centres has been improvedin the year in question. RCs now have access during sitevisits to up to date information about the progress ofhospitals and treatment centres in terms of the NJR’s ownperformance indicators and are able to identify trends.


2.5.7 Regional Clinical CoordinatorsIn addition to Regional Coordinators there are NJR RegionalClinical Coordinators (RCCs), who are consultant orthopaedicsurgeons. These are honorary posts with the primary role toact as NJR local ‘champions’, working with colleagues andteams in units within their area to ensure that the purposeand benefits of the NJR are understood and to encouragecompliance with NJR data requirements.

The RCCs are provided with regular reports about the overallperformance of units in their area. They work closely withRCs, providing advice and support that will enable them toassist individual units to improve performance.

The RCC Network advises the NJR Centre on orthopaedicmatters and met four times during 2006/07. All memberswere involved in the review of the NJR dataset (see Section2.4). The RCC Network Chair is an RCC who is appointed tothe post following interview by the Department of Health.The RCC Network Chair has an ‘observer’ seat on the NJRSteering Committee.

During the year in view, a change in the RCC Network wasnecessary in order to tie in with England’s new SHA(Strategic Health Authority) structure. There are now twoRCCs per SHA and one per Welsh NHS region. New termsof reference were drafted for RCCs (see Appendix 4).

2.5.8 NJR Steering CommitteeThe programme of work for the NJR is set and monitored by the NJR Steering Committee (NJRSC) in conjunction withthe Department of Health. The NJRSC met four times during2006/07. The minutes of the meetings are posted on theNJR website (http://www.njrcentre.org.uk/documents/steeringcomm/sc_index.htm).

In October 2006, the NJR Steering Committee adopted its newconstitution in line with its re-designation from departmentalcommittee to advisory non-departmental public body.

The term of office for all but one member of the SteeringCommittee expired in 2006/07, with the last one ending on30 April 2007. The Committee’s current members wereappointed by the Appointments Commission during 2006/07on behalf of the Secretary of State for Health following aformal recruitment process (for a list of full members andobservers see Appendix 1 and NJR websitehttp://www.njrcentre.org.uk/documents/steeringcomm/sc_index.htm). Recruitment was targeted towards Northern Ireland,as well as England and Wales, reflecting the intention toextend the geographical area of the NJR to include NorthernIreland. A patient representative member was appointedfrom Northern Ireland and one from Wales. An induction day was provided for Steering Committee members on 21 September 2006.

Following a review it was decided to absorb the work of theNJR Outlier Performance Advisory Group (NOPAG), EditorialBoard, Patient Reported Outcomes Measurement Study andResearch Sub-Committees into the work of the SteeringCommittee. This ensured that all NJR Steering Committeemembers had an opportunity to contribute to the full rangeof work.

Firmer links were forged with the RCC Network through theassignment of the three surgeon members of the NJRSC tosupport their RCC colleagues. An observer seat has beenprovided on the NJRSC for the RCC Network Chair andminutes between the RCC Network and the NJR SteeringCommittee continued to be exchanged.

2.6 Information, Communicationand Monitoring

Keeping stakeholders informed

The need to provide timely and accurate information tostakeholders is a priority and the NJR Centre is makinginformation available in a variety of ways. During 2006/07 itintroduced a performance management system to helpmanage the information submitted to, and held, on NJR.This enabled the NJR Centre to make the improvementsoutlined below.

2.6.1 NJR ReportsOnlineInformation about operations, case mix and implant usagecan now be found in a range of reports for surgeons andhospital data managers. These are published in NJRReportsOnline, which went live in October 2006 and enablessurgeons not only to look at all the operations they haveperformed but also to study the different types of operation(case mix) and the profile (e.g. age and sex) of the patientsundergoing the surgery. They may also look at the type andnumber of implants they have used for those procedures.They may see this information for each of the hospitals withwhich they are registered. Access is controlled so that only a surgeon can see surgeon reports and only surgeons cansee information about the operations that they themselveshave undertaken. In addition, the reports are anonymised so that patients cannot be identified from the informationprovided. Surgeons are, however, entitled to see any NJRdata relating to a patient in their care.

2.6.2 Performance monitoringNew management reports closely monitor all aspects of theperformance of units in terms of their entry of data on NJR(compliance) and patient consent, helping to focus on thesupport required from the NJR Centre for individual units.


2.6.3 NJR StatsOnlineNJR StatsOnline is accessible to all through the NJR website(http://www.njrcentre.org.uk/StatsOnline/) and providesinformation, updated monthly, on all independent healthcareand NHS hospitals and treatment centres in England andWales that carry out hip and knee joint replacements. Thisinformation includes the total number of operations submittedto the NJR, the number of hip and knee joint replacementprocedures and the percentage of records that have NJRpatient consent.

The format of NJR StatsOnline was changed during 2006/07to reflect England’s new SHA (Strategic Health Authority)structure and to provide information based on operationdate as well as submission date. During the year ahead,NJR StatsOnline will be enhanced with further information toenable more effective comparisons to be made betweenoperations. In addition, information will be provided toenable comparisons to be made at national, SHA, NHS trustand unit (hospital and treatment centre) levels.

2.6.4 Information BureauThe NJR Centre provides an Information Bureau, whichsupplies tabulations or extracts of NJR data and other NJRinformation in response to specific requests. All informationis released with due regard to patient and clinician confidentialityand, in the case of implant information, to commerciallysensitive information.

An NJR Information Sharing and Governance Protocol,outlining the operations and guidelines for the release ofinformation9, is due to be published on the NJR websiteduring 2007.

2.6.5 HES linksDuring 2006/07 the NJR Centre made progress on a methodof linking with HES patient records that date back to 1989.This work is important as it will:

• make available more data that can be used for analysisof NJR data

• improve outcomes based analysis for stakeholders

• enable more accurate monitoring of compliance with NJRdata requirements.

A similar link is planned be implemented between the NJRand PEDW.

2.6.6 CommunicationsCommunication with NJR stakeholders during the year inview involved:

• increased direct support for units contributing low levels ofdata or data with unacceptably low rates of patient consent

• holding the initial regional workshop and presenting atorthopaedic audit and training meetings to informstakeholders of planned service developments and toencourage participation in the NJR

• NJR Centre staff attending audit and training meetings ina number of hospitals, see Appendix 8

• publicising planned developments for the service throughattendance at conferences including the BritishOrthopaedic Association, British Hip Society and BritishAssociation for Surgery of the Knee in addition to theNuffield Hospitals Conference and Training Seminar.

2.6.7 PublicationsSeveral publications were produced during 2006/07,reporting on NJR data or services. These publications, which may be found on the NJR website, included:

• National Joint Registry Annual Report 2005/06

• National Joint Registry 3rd Annual Clinical Report

• one issue of the NJR Newsletter, Joint Approach

• a starter pack of information about the NJR, guidelinesand user manuals for new unit staff.

2.6.8 Communications strategyThe NJR Centre has started work on a communicationsstrategy to assess the most effective ways of communicatingwith stakeholders, including orthopaedic surgeons, seniorNHS and independent healthcare managers, unit staff,suppliers, regulatory agencies and patients.

New patient information posters for out-patient departmentsand pre-operative assessment sessions are planned for 2007.

9 The Department of Health (DH) is the Data Controller, NorthgateInformation Solutions Ltd is the Data Processor on behalf of the DH as theholder of the contract for the management of the NJR

Part 13. Finance



3.1 Income and Expenditure

The NJR is self-financing, funded by a levy raised on the saleof hip and knee implants to NHS and independent healthcareproviders in England and Wales. The rate of the levy is set bythe Health Minister and is subject to a Memorandum ofUnderstanding between the Department of Health, theNational Assembly for Wales, the Independent HealthcareForum and the Association of British Healthcare IndustriesOrthopaedic Special Interest Section.

Income to the NJR for 2006/07 was £2,618,626.37 andexpenditure for the same period was £2,057,800.38.

Members of the NJRSC and the RCC Network are volunteersand do not receive payment for their work. However, they arereimbursed for any travel and subsistence expense incurredwhile attending meetings. The total expenditure for members’expenses during 2006/07 was £18,650.36.

3.2 Changes to the Levy

The levy was reduced from £25 to £23 on 1 June 2006 and,following a review by the NJRSC and the Health Minister, itwill be further reduced to £20 from 1 June 2007.

Part 14. Taking the NJR Forward



4.1 Improving Data Quality and Completeness

To deliver the NJR aims it is essential that the data held onthe Registry is complete and of good quality. As detailedearlier in this document, the targets set involve reaching thefollowing levels by June 2008:

• 95% compliance (case ascertainment) – the proportion ofall hip and knee joint replacement operations for whichrecords are submitted to the NJR

• 90% consent – the proportion of records submitted to theNJR which include patient consent to store personal details

• 90% linkability – the proportion of records submitted toNJR with information which would allow them to be linkedto other records on the same patient for analysis purposes.

4.2 Service Development

Reference has been made in this Report to a number ofdevelopments, which are summarised here.

• Subject to approval, implementation of a new dataset(MDSv3), which will reduce the amount of data requiredfrom units and improve NJR data.

• Linking NJR data to HES and PEDW data to provide moreinformation for analysis.

• Continuing to improve the data and information madeavailable through NJR StatsOnline and NJR ReportsOnline.

• Developing communications and working relationshipswith orthopaedic surgeons, healthcare management,patients and other stakeholders.

• Looking at ways to improve integration of the NJR withother databases to reduce the need to enter the samedata several times and to ensure that it is able to keeppace with future developments such as the NationalProgramme for IT (Information Technology)10.

• Improving the NJR website so that information may bemore easily found and enhancing communication withother key stakeholders.

4.3 The Future

The intention is to extend the geographical area covered bythe NJR to include Northern Ireland.

The NJR Centre will monitor the development and progressof NJR in relation to other national hip and knee jointreplacement registries and take action as appropriate indiscussion with the NJRSC and Department of Health.

Regional Clinical Coordinators will continue to be the local champions of the NJR, working closely with NJR Regional Coordinators.

4.4 NJR Steering Committee

The Committee membership under the new constitution was completed by 1 May 2007, allowing new and existingmembers to work together to fulfil NJRSC’s role as anadvisory non-departmental public body. It will continue towork with the Department of Health to set the work programmefor, and oversee the activities of, the NJR, advising HealthMinisters, hospitals and suppliers as required.

10 The National Programme for IT (NPfIT) will improve patient care by creatingan NHS Care Records Service to improve access to patient informationacross the NHS, making it easier and faster for GPs and other primary carestaff to book hospital appointments for patients, providing a system forelectronic transmission of prescriptions and ensuring that the ITinfrastructure can meet NHS needs now and in the future

Part 1Appendices



Appendix 1 – NJR Steering Committee 2006/07

1.1 NJR Steering Committee – Composition

As an advisory non-departmental public body, the compositionof the NJRSC is:

• Chair 1

• Orthopaedic surgeons 3

• Patient Representative Groups 2

• Implant manufacturer/supplier industry 2

• Public health/epidemiology 1

• NHS organisation management 1

• Independent healthcare provider 1

• Practitioner with special interest in orthopaedic care who is a GP, nurse or allied health professional (physiotherapist or occupational therapist) 1

1.2 Membership as at 30 September 2006

Membership including members appointed under the previous constitution.

Mr William Darling Chair

Professor Paul Gregg Vice Chair

Mrs Judy Murray British Orthopaedic Association

Mr Martyn Porter British Hip Society

Mr Tim Wilton British Society for Surgery of the Knee

Ms Christine Miles NHS Trust Management

Mr Michael Borroff Orthopaedic Device Industry

Mr Ken Bateman Orthopaedic Device Industry

Ms Christine Edwards Patient Group (Arthritis Care)

Mr Colin Thomson Patient Group (All Wales Community Health Councils)

Professor Alex MacGregor Public Health and Epidemiology

Miss Carolyn Naisby Practitioner with Special Interest in Orthopaedics (from 1 July 2006)

Mrs Ros Gray Independent Healthcare Sector (from 1 July to 15 September 2006)


Membership from 1 October 2006

With members appointed under new constitution as post became vacant:

1.3 Attenders

The following have regularly attended NJRSC meetings:

* Mr Keith Tucker joins as Orthopaedic Surgeon from 1 May 2007

Mr William Darling Chair

Professor Paul Gregg Orthopaedic Surgeon Vice Chair (from 31 January 2007)

Mr Martyn Porter Orthopaedic Surgeon

Mr Tim Wilton British Society for Surgery of the Knee (to 30 April 2007)*

Mrs Patricia Durkin Representing Patients (from 1 March 2007)

Mr Colin ThomsonPatient Group (All Wales Community Health Councils) (to 28 February 2007)

Mr Michael Borroff Orthopaedic Device Industry

Miss Carolyn Naisby Practitioner with Special Interest in Orthopaedics

Miss Mary Cowern Representing Patients

Professor Alex MacGregor Public Health and Epidemiology

Mr Anthony Lowther Orthopaedic Manufacturing/Supply Industry (From 1 October 2006)

Mr Andrew Woodhead NHS Trust Management (From 4 January 2007)

Mrs Patricia Cassidy Independent Healthcare Sector (From 19 April 2007)

Mr Andy Smallwood NHS Purchasing and Supply Agency (PASA) now NHS Supply Chain

Mr Andy Crosbie Medicines and Healthcare Products Regulatory Agency (MHRA)

Ms Ramila Mistry Department of Health

Ms Kate Wortham Department of Health

Mrs Christine Miles Welsh Assembly Government


1.4 NJR Steering Committee Members’ Declarations of Interest

Mr Michael BorroffChair of ABHI Orthopaedics Special Interest Section and currently employed by DePuy International Ltd manufacturer oforthopaedic prostheses.

Mr Ken BatemanVice-chair of Orthopaedics Special Interest Section of Associationof British Healthcare Industries (ABHI).Employed by Smith & Nephew Orthopaedics UK Ltd.

Mrs Patricia Cassidy Group Clinical Director, Nuffield Hospitals.

Miss Mary Cowern None

Mr William DarlingManaging Director J, M and W Darling Ltd, Managing Director Galen Pharmacy Ltd. Chair South Tyneside Standard Committee.

Mrs Patricia Durkin CHKS Health Care Consultancy fee paid work and share holder.

Ms Christine Edwards None

Mrs Ros Gray Group Clinical Director, Nuffield Hospitals.

Professor Paul Gregg

Consultant Orthopaedic Surgeon at South Tees Hospitals NHS Trust. Unit receives research/audit funding from DePuyInternational Ltd, StrykerUK and Smith & Nephew plc. Orthopaedic advisor for Capio Healthcare.

Professor Alexander MacGregorProfessor of Chronic Disease Epidemiology, University of East Anglia.Consultant Rheumatologist at Norfolk and Norwich UniversityHospital NHS Trust.

Mr Anthony LowtherSales Director UK and Eire with Zimmer Ltd, manufacturer oforthopaedic prostheses.

Ms Christine MilesDirector of Delivery & Support Unit Wales and employee ofBroMorgannwg NHS Trust.

Mrs Judy Murray Trauma and Orthopaedic Consultant, Royal Glamorgan Hospital.

Miss Carolyn NaisbyConsultant Physiotherapist, City Hospitals Sunderland NHS Foundation Trust.

Mr Martyn Porter

Consultant Orthopaedic Surgeon Wrightington, Wigan andLeigh NHS Trust. Work at a unit that has received financialsupport from DePuy International for clinical and RSA studiesfor Elite Plus femoral stem and C-stem. Has acted as Consultant to DePuy International for development ofa hip femoral stem (C-stem AMT).

Mr Colin Thomson None

Mr J Keith Tucker

Consultant Orthopaedic Surgeon Norfolk and Norwich UniversityHospital NHS Trust, various sources of financial support forresearch undertaken by orthopaedic department. Paid royalties byJohnson and Johnson Orthopaedic more than 5 years ago forcontribution to design of hip prostheses. All royalties paid toorthopaedic charity.

Mr Tim Wilton Consultant Orthopaedic Surgeon, Derby Royal Infirmary.

Mr Andrew Woodhead Chief Executive Royal National Orthopaedic Hospital NHS Trust.


Appendix 2 – NJR Steering Committee Terms of Reference11

The National Joint Registry Steering Committee (NJRSC) is responsible for:

• Setting the programme of work for the NJR Centre, in conjunction with the Department of Health.

• Ensuring that appropriate stakeholders are involved in andconsulted on the work of the NJR Centre, as appropriate.

• Recommending any significant changes to the contractbetween the contractor responsible for the NJR Centreand the Department of Health, including consideration of value for money.

• Monitoring the codes of conduct applied to the contractorin its relationship with other key stakeholders (orthopaedicunits within NHS and independent healthcare organisationsand with the orthopaedic implant industry).

• Monitoring the delivery and quality of the work of the NJR against the contract in conjunction with the Departmentof Health.

• Monitoring the inclusion, closure and performance of orthopaedic units contributing data to the NJR.

• Providing advice about the performance of prosthesesand best surgical practice to ministers, the Department of Health, the National Assembly for Wales, providers oforthopaedic services and, in the future, Northern IrelandDepartment of Health Social Services and Public.

• Reviewing the NJR levy on an annual basis with theDepartment of Health and making recommendations to ministers on the amount at which it should be set.

• Providing an Annual Report to ministers on the work of the NJR and, with ministerial agreement, to make theReport available in both English and Welsh.

• Facilitating, where appropriate, the use of NJR data forresearch purposes.

• Adhering to the terms of the Code of Practice for NationalJoint Registry Steering Committee Members12 and theCode of Practice – Register of Interests13.

11 For further information about the NJRSC rules, publication scheme, chair andmembers duties and roles, code of practice for members and declaration ofinterests, see the NJR Steering Committee Members’ Handbook, availablefrom the NJR website (www.njrcentre.org.uk) under information on the NJRSteering Committee

12 See Section 4 of the NJR Steering Committee Members’ Handbook

13 See Section 5 of the NJR Steering Committee Members’ Handbook


Appendix 3 – Regional Clinical Coordinators

Regional Clinical Coordinators (RCCs) Mr Peter Howard - RCC Chair

South West Strategic Health AuthorityMr Evert SmithMr Nick Fiddian

West Midlands Strategic Health AuthorityMr David DunlopMr Ian D M dos Remedios

North West Strategic Health Authority Mr Glyn ThomasMr David Sochart

North East Strategic Health AuthorityMr John AndersonProfessor Andrew McCaskie

East of England Strategic Health AuthorityMr Matthew PorteousMr Godfrey Charnley

South Central Strategic Health Authority Mr John Britton

South East Coast Strategic Health AuthorityMr Hagen JahnichMr Guy Selmon

East Midlands Strategic Health AuthorityMr Colin EslerMr Peter Howard

London Strategic Health AuthorityMr Mark RowntreeMr Gareth Scott

Yorkshire and Humberside Strategic Health Authority Mr Ian Stockley

Mid and West Wales Mr David Woodnutt

North Wales Mr Glynne Andrew

South East Wales Mr Robin Rice


Appendix 4 – Regional Clinical Coordinators’ Network Terms of Reference

The National Joint Registry Regional Clinical CoordinatorsNetwork (NJR RCC Network) RCC members have aresponsibility to:

• Facilitate and improve NJR compliance and patientconsent rates and the quality of data submitted to the NJR by individual NHS Trusts and private healthcareproviders in their region14.

• Establish regular interaction with relevant NJR RegionalCoordinators (RCs) to achieve the RCC role.

• Assist the Regional Co-ordinators to encourage andsupport the poorly performing NHS Trusts and privatehealthcare providers in their region to submit the required NJR data.

• Provide input to determining appropriate reporting,analysis and interpretation of their region’s data and theoverall NJR data.

• Facilitate feedback of NJR data to their region’s NHSTrusts and private healthcare providers orthopaedicsurgeons, hospital managers and other appropriatestakeholders on a monthly to quarterly basis.

• Host training roadshows and regional seminars to raiseawareness of the NJR and feedback information.

• Communicate between the regionally based hospitals/orthopaedic units / treatment centres and the NJRSC, NJR Centre (contractor) and DH to achieve the aims of NJR.

• Provide continued support to the functioning of the NJR.

• Attend the NJR RCC Network meetings on a regular basisand contribute.

• Provide representation at meetings/committees for NJR at regional & national level as required.

• Provide representation on organising committees for NJR-related events.

Note: In considering issues at national level, NJR RCCNetwork meeting will adopt a UK perspective, which willinclude taking account of differences between England,Wales and Northern Ireland, and of the status of devolvedand non-devolved matters.

14 ‘Region’ means SHA in England, Region in Wales and Northern Ireland


Appendix 5 – NJR Services to Stakeholders

NJR 1st, 2nd, and 3rd Annual Reports available on websitewww.njrcentre.org.uk (3rd released in 2 documents shortly after theBritish Orthopaedic Association (BOA) Annual Congress inSeptember 2006)

Surgical professions (including British Orthopaedic Association,Royal College of Surgeons), patients and public, industry(orthopaedic implant suppliers), public health specialists andepidemiologists, hospital/unit staff, NHS and independenthealthcare management (including Independent HealthcareAdvisory Service), NHS Supply Chain, Medicines and HealthcareProducts Regulatory Agency (MHRA), NJR Steering Committee,Department of Health, Welsh Assembly, others

NJR website (www.njrcentre.org.uk) provides all key informationabout the NJR for both the public and the healthcare staff

All stakeholders

NJR StatsOnline available to NHS units and IndependentHealthcare Sector units in England and Wales. Provides ‘easy toview’ information about unit performance against key performanceindicators and benchmarking of performance against other units,Strategic Health Authorities and nationally. NJR StatsOnline issubject to continuous review and enhancement

Department of Health, Welsh Assembly Government, surgicalprofessions, patients and public, hospital staff including data entrystaff, NHS and independent healthcare management

NJR ReportsOnline launched October 2006, providing reports tokey staff about operations undertaken in units, the implants used,and other, management information

Surgeons, suppliers, and NJR staff in hospitals

NJR newsletter: Joint Approach November 2006 Surgical professions (including BOA and RCS), hospital staff anddata entry staff

Ability to be able to access non-patient identifiable information Surgical professions (including BOA and RCS)

Bar code reader to assist data entry Hospital data entry staff

Detailed, real time information for the Regional Coordinators toenable them to provide direct support to units and to identify anypotential problems and intervene early

Surgeons, Hospital data entry staff. NHS and independenthealthcare management

Patient consent – Good practice guides and case studies Hospital and data entry staff, NHS and independent healthcare management

NJR patient consent leaflet and patient information leaflets printedand distributed regularly to all units

Patients and public, hospital and data entry staff and independenthealthcare management

Attendance at conferences and exhibitions to inform units and staffof the role and benefits of the NJR

Surgeons, NHS and Independent Healthcare unit management andNJR staff, suppliers and manufacturers of implants

Regional Workshops and Roadshows to inform stakeholders ofservice development and plans, seek unit feedback and ideas, and to allow the direct sharing of best practice between units

Hospital staff, including surgeons

An ‘Information Bureau’ which provides information regularly tosuch stakeholders as NHS Supply Chain and on an ad hoc basis,including requests made under the Freedom of Information Act

All stakeholders, including members of the public


Appendix 6 – NJR Units Not Returning Data in 2006/07

The following NHS and independent healthcare providers made no returns to NJR between 1 April 2006 and 31 March 2007.Any unit that only performs trauma hip and knee replacements are omitted from the list below.

Name of Trust Hospital name

Barking, Havering and Redbridge Hospitals NHS Trust Harold Wood Hospital

Bolton Hospitals NHS Trust The Royal Bolton Hospital

Bromley Hospitals NHS Trust Princess Royal University Hospital

Leeds Teaching Hospitals NHS Trust Leeds General Infirmary

Newham University Hospital NHS Trust Gateway Surgical Centre

University College London Hospitals NHS Foundation Trust University College Hospital

Wrightington, Wigan and Leigh NHS Trust Royal Albert Edward Infirmary

Surrey and Sussex Healthcare NHS Trust Crawley Hospital


Appendix 7 – Supporting Data for Figures

Year NJR records Levy Compliance (%)

2003/04 62,191 156,354 40%

2004/05 107,172 155,725 69%

2005/06 132,578 160,960 82%

2006/07 131,378 161,522 81%

7.1 Supporting data for Figure 1 – NJR Compliance: 2003 – 2007, based on levies from implant sales

7.2 Supporting data for Figure 2 – NJR Consent: quarterly analysis of total records receivedand those with patient consent, 2003/04 – 2006/07

Year Quarter Number of operationson NJR

Number of operationson NJR with consent

Consent rate (%)

2003/04 Q1 8,158 5,468 67%

Q2 13,964 8,744 63%

Q3 16,071 10,516 65%

Q4 23,998 14,705 61%

2004/05 Q1 23,931 14,390 60%

Q2 27,369 16,273 59%

Q3 24,902 16,513 66%

Q4 30,970 21,658 70%

2005/06 Q1 32,268 21,895 68%

Q2 30,742 22,262 72%

Q3 32,021 24,581 77%

Q4 37,547 29,238 78%

2006/07 Q1 31,128 24,728 79%

Q2 30,538 24,498 80%

Q3 32,734 26,724 82%

Q4 36,978 30,746 83%


7.3 Supporting data for Figure 3 – NJR Linkability: analysis of total records received andthose for which NHS numbers have been traced, 2003/04 – 2006/07

7.4 Supporting data for Figure 6 - Provider: distribution of hip and knee replacementoperations by provider organisation, NJR records, for the three years 2004/05 to 2006/07

Year Number of operations Number with NHS Number traced

Linkage rate (%)

2003/04 62,191 27,807 45%

2004/05 107,172 51,580 48%

2005/06 132,578 79,733 60%

2006/07 131,378 90,502 69%

NHS TreatmentCentre

NHS hospitalsIndependent

hospitalsIndependent

Treatment CentreTotal

2003/04 219 40,669 20,971 332 62,191

2004/05 3,202 69,300 32,818 1,852 107,172

2005/06 7,294 81,535 39,635 4,114 132,578

2006/07 7,572 86,979 30,444 6,383 131,378


Appendix 8 – Locations of Audit and Training Meetings

Withybush Hospital (Pembrokeshire and Derwen NHS Trust)

Sandwell Hospital (Sandwell and West Birmingham Hospitals NHS Trust)

Royal United Hospital in Bath (Bath Royal United Hospital NHS Trust)

London Clinic (Independent healthcare company)

Part 21. Introduction



Part 2 of the NJR 4th Annual Report summarises the data forhip and knee procedures carried out between 1 January to 31 December 2006 in England and Wales and entered intothe NJR by 28 February 2007. The Annual Report also includes a description of outcomes after hip or kneereplacement, based on procedures entered into the NJRsince the start of data collection in April 2003 with, for thefirst time, a more extensive analysis than was possible previously.

It is possible to provide analyses of outcomes, such asrevision and mortality, based on the number of jointreplacements that have been entered into the NJR sinceApril 2003 and the length of time that the NJR now allowspatients to be followed up after their joint replacement. The ability to determine whether patients have had a revision of their joint replacement has been further enhanced by linking the NJR data with records from theHospital Episode Statistics (HES) database for this Report.HES is an administrative database of all NHS or privatelyfunded admissions to NHS hospitals in England, as well as admissions of NHS funded patients treated in theindependent sector. Data from the mortality registry of theOffice for National Statistics (ONS) is also included in HES.The NJR provides information about the procedure, such as the surgical practice followed and the type and brand ofprostheses used. The HES database provides post-operativeinformation that is not available in the NJR, such as thelength of hospital stay. Furthermore, the availability of dataon all hospital admission episodes for a given patient in HES provides information about whether revision surgeryhas been carried out and about any other re-admission thatmay be related to the primary replacement procedure. Thelinked database therefore offers a unique opportunity tostudy outcomes after joint replacement that would not beavailable from either database alone.

Based on analyses of the linked NJR-HES data on hip andknee replacements carried out in England, mortality andrevision rates are presented as a function of time aftersurgery. The impact of patient characteristics, the type ofprocedure as well as the type of provider, is also explored.Furthermore, revision rates are presented for a number offrequently used prostheses brands. Special attention hasbeen given to the outcomes after hip resurfacing andunicondylar knee replacement. The outcomes after thesetypes of replacements have been compared againstalternative types. All the comparisons described above were carried out using multivariable analyses in order to take into account that patients treated in the NHS mightdiffer from those treated in the independent sector, or thatthose undergoing a particular type of joint replacementprocedure, such as hip resurfacing or a unicondylar kneereplacement, might differ from patients undergoing othertypes of procedures. A comparison of revision rates after hip and knee replacement against results presented in othernational registries will also be provided.

This is the first time that linkage between NJR and a hospitaladministrative database has been undertaken. Linkage hasbeen performed using the HES database. HES contains recordlevel details of procedures carried out in England that arefunded by the NHS or independently funded and undertakenin the NHS. The reduced coverage of HES relative to NJRmeans that this linkage will not include independently fundedprocedures undertaken in independent sector centres, and willalso exclude all procedures undertaken in Wales. In future,subject to appropriate approvals, data for patients who haveundergone hip or knee replacement procedures in Wales willbe included in the outcome analyses through a similar linkageprocess using the Patient Episode Database for Wales (PEDW),the Welsh equivalent of HES.

The limited coverage of the linked database means that careshould be taken in generalising the results of the outcomeanalyses to all hip and knee replacement procedures inEngland and Wales, particularly when comparing providertypes. Differences in patient characteristics, procedure andprovider types between the linked database and those thatcould not be linked are explored in the Report (Section 2).

A brief description of compliance and linkage of the NJRwith HES is made in Section 2, with the aim of establishingwhether the quality of the data presented in the Report issuch that it can be considered to be representative of jointreplacement practice in England and Wales. Section 3 thengives an overview of the numbers of hip and knee procedurescarried out in 2006 in England and Wales according to thetype of provider (e.g. NHS, treatment centre and independentsector) and source of funding. The succeeding two Sectionsfirst present the characteristics of patients who underwent a joint replacement, the type of replacement and surgicaltechnique used for procedures in 2006. Outcomes in termsof revision of the prostheses, mortality and length of hospitalstay of the patient are then presented for procedures in theNJR-HES linked database. The results are presented separatelyfor hip and knee replacement, with special attention given tohip resurfacing and unicondylar knee replacement. The lastSection presents the types and brands of prostheses thatwere used in 2006.

In order to establish trends over time, in each Section thedata presented for 2006 are compared with NJR data enteredin 2004 and 2005 (see previous Annual Reports). The text ineach Section summarises the detailed results presented inTables at the end of the Section, with appropriate referencesgiven to the relevant Table.

Part 22. Compliance and Linkage to the

Hospital Episode Statistics Database



The level of completeness of joint procedures reported tothe NJR is an important factor that determines whether theresults presented in the Annual Report can be considered tobe representative of joint replacement practice in Englandand Wales. In this section, the rate of compliance, which isdefined as the proportion of all joint procedures undertakenin England and Wales in 2006 that were entered into theNJR by 28 February 2007 is presented. The outcomeanalyses presented in the Report were based on theprocedures entered in the NJR since the start of datacollection in April 2003 that were also in the HES-linkeddatabase. The characteristics of these procedures aresummarised in this Section and compared to those of theprocedures that could not be linked to a HES episode.

2.1 Compliance for Procedures Undertakenin 2006

A levy is collected to cover the costs of the NJR at each sale ofa specific hip or knee component. A single leviable componentis used for most joint procedures. A levy might not be collectedin exceptional cases, such as when custom-made implants areused or when a revision operation does not involve removaland replacement of the leviable component. However, acomparison of the number of joint replacements reported tothe NJR with the number of levies collected gives a reasonableapproximation of the rate of compliance (case ascertainment).

The total number of levies collected in England and Walesfrom 1 January to 31 December 2006 was 154,066 and thetotal number of hip and knee joint procedures reported tothe NJR was 122,442. This suggests that the compliancerate was 79% for procedures carried out during the 2006calendar year in the NHS and the independent sector.Compared with previous years, the rate of compliance hasimproved. The compliance rate was 77% in 2005 (124,036procedures out of 161,735 levies collected) and 60% in 2004(93,885 procedures out of 155,450 levies collected).

2.2 Linkage of NJR Procedures to HES Episodes

Hip and knee joint procedures carried out in England and Walesin the NHS as well as the independent sector have beenentered into the NJR since 1 April 2003. At the time of analyses,data from HES was available for hospital admissions up to30 September 2006. In this first undertaking of linkage betweenthe NJR and a hospital administrative database, only thoseprocedures carried out in England and entered in to HESwere used in the linkage. In future, procedures entered intoPEDW, the equivalent of HES for procedures undertaken inWales, will also be linked with the NJR. Therefore, for thisAnnual Report, only those procedures undertaken between1 April 2003 and 30 September 2006 at centres in Englandcould potentially be linked to a HES episode. Furthermore,the HES database includes only those procedures fundedby the NHS or those that are independently funded andundertaken in NHS hospitals. Consequently, the limitedcoverage of HES relative to the NJR means that linkage willnot be possible for independently funded proceduresundertaken at independent sector centres in England, or forall procedures undertaken in Wales.


HES

355,480 hip or knee joint replacementssince April 2003 (Procedures in the NHS and NHS funded procedures in the Independent

Sector in England only)

337,908 primary procedures23,563 revisions and other

re-operations

173,350 linkedprimary procedures

327,557 primary procedures27,923 revisions and other

re-operations

Revision ratesMortality

Length of stay

NJR – HESLINKAGE

NJR

361,471 hip or knee joint replacementsentered since April 2003

(England only)

1,015 first revision procedures(excluding re-operations)

identified in HES

Figure 2.1Flow chart illustrating linkage of the NJR with HES


2.2.1 Linkage process

Figure 2.1 shows a flow chart illustrating the process oflinkage of NJR procedures to HES episodes. Linkage of anNJR procedure to a HES episode was attempted using thelocal hospital number and NHS Trust code, provided thedate of operation recorded in the NJR was within the episodestart and end dates in HES. An NJR procedure was classifiedas being HES-linked if linkage to a HES episode was achievedusing this linkage method.

2.2.2 Coverage of linked procedures

All analyses of revision rates, mortality and length of stay werebased on procedures that were linked to a HES episode.Revisions were used in the estimation of revision rates only if the corresponding primary procedure was included in thelinked database. Therefore, only those revisions undertakensince April 2003 and recorded in HES were included. Detailsof how revisions were identified are given in Sections 4.2and 5.2.

An issue of concern is the potential for systematic differencesbetween the patients whose procedures were HES-linkedand those who were not HES-linked (see Table 2.1) – Tables2.2 and 2.3 show a comparison of characteristics betweenHES-linked and non-HES linked procedures for hip and kneejoint replacements. The non-HES linked procedures inTables 2.1 to 2.3 exclude the procedures undertaken in Wales,for which linkage was not possible. However, as funding isnot a mandatory field and not completely reported, it wasnot possible to exclude from the non-HES linked proceduresall privately funded procedures undertaken in the independentsector, for which linkage was also not possible.

Of all 355,480 hip or knee replacement procedures recorded inHES between April 2003 and September 2006 and undertakenat NHS hospitals and NHS treatment centres, or undertakenin the independent sector and funded by the NHS, 187,220(52%) were included in the linked database. However, thenumber of procedures linked differed between provider types.Slightly more than 70% of hip or knee replacement proceduresundertaken at NHS hospitals or treatment centres werelinked to a HES episode (Table 2.1). Fewer procedures werelinked for Independent Sector Treatment Centres (ISTCs)(27% for hip replacements, 24% for knee replacements) andindependent hospitals (6% for hip replacements, 8% forknee replacements). Therefore, the HES-linked proceduresare more representative of procedures undertaken in NHShospitals and Treatment Centres.

Of all HES-linked procedures, 4% of hip (3,232) or knee(4,034) replacements were undertaken at independenthospitals (Tables 2.2 and 2.3). In comparison, of the non-HES linked procedures 60% (54,480) of hipreplacements and 55% (45,147) of knee replacements wereundertaken at independent hospitals. A comparison of patientcharacteristics between the HES-linked procedures and thosethat were not HES-linked showed that differences in thetypes of patients between these two groups of procedureswere marginal (Tables 3.2 and 3.3). The differences betweenHES-linked and non-HES-linked procedures should beborne in mind when interpreting the results presented in therest of the Report.


2 Compliance and Linkage to the Hospital Episode Statistics Database

Table 2.1Hip or knee joint replacement procedures carried out in England between 1 April 2003 and 30 September 2006 that werelinked to a HES episode, by provider type

* The total number of procedures presented excludes procedures undertaken inWales as these procedures were not HES-linkable (see Section 2.2)

Hip joint replacements

Total hip replacement using cement

Total hip replacement not using cement

Hybrid or reverse hybrid total hip replacement

Hip resurfacing

Revisions and other re-operations

Total

Knee joint replacements

Total knee replacement using cement

Total knee replacement not using cement

Hybrid total knee replacement

Unicondylar knee replacement

Patello-femoral replacement

Revisions and other re-operations

Total

Total*

55,550

24,071

15,804

8,247

11,357

115,029

88,729

7,047

1,384

8,426

1,144

7,628

114,358

n

40,803

18,504

10,187

6,074

8,053

83,621

66,798

5,318

971

4,187

673

5,285

83,232

%

73%

77%

64%

74%

71%

73%

75%

75%

70%

50%

59%

69%

73%

26,960

12,644

8,368

7,171

2,269

57,712

37,377

3,438

893

5,169

676

1,628

49,181

n

1,729

670

478

289

66

3,232

3,057

494

183

216

28

56

4,034

%

6%

5%

6%

4%

3%

6%

8%

14%

20%

4%

4%

3%

8%

3,157

2,270

1,008

542

389

7,366

7,039

722

162

289

52

197

8,461

n

1,948

1,724

665

329

263

4,929

4,874

546

104

112

30

136

5,802

%

62%

76%

66%

61%

68%

67%

69%

75%

64%

39%

58%

69%

69%

1,960

1,562

683

113

56

4,374

4,416

368

51

102

14

39

4,990

n

573

448

116

31

7

1,175

1,009

159

4

16

3

4

1,195

%

29%

29%

17%

27%

13%

27%

23%

43%

8%

16%

21%

10%

24%

87,627

40,547

25,863

16,373

14,071

184,481

137,561

11,575

2,490

13,986

1,886

9,492

176,990

n

45,053

21,346

11,446

6,723

8,389

92,957

75,738

6,517

1,262

4,531

734

5,481

94,263

%

51%

53%

44%

41%

60%

50%

55%

56%

50%

32%

39%

58%

53%

Total* Total* Total* Total*HES-linkedprocedures

HES-linkedprocedures




NHS hospitals

Provider type

Independent hospitals NHS TCs Independent TCs All provider types


Table 2.2Comparison of patient, procedure and provider type for HES-linked and non HES-linked hip replacement procedures, 1 April 2003 to 30 September 2006*

Linked to a HES episode Not linked to a HES episode Total number of proceduresthat were HES-linkable*

Total 92,957 91,524 184,481

Age, years (consenting patients only) n

74,931 54,582 129,513

Mean (sd) 68 (12) 68 (12) 68 (12)

Interquartile range 61 - 76 61 -76 61 - 76

n % n % n %

Gender (consenting patients only) n

Male 30,577 41% 22,017 40% 52,594 41%

Female 44,350 59% 32,573 60% 76,923 59%

Patient physical status

P1 – Fit and healthy 21,929 24% 29,652 32% 51,581 28%

P2 – Mild disease not incapacitating 55,935 60% 51,873 57% 107,808 58%

P3 – Incapacitatingsystemic disease

14,272 15% 9,435 10% 23,707 13%

P4 – Life threatening disease 750 1% 532 1% 1,282 1%

P5 – Expected to die within 24hrs 71 <1% 32 <1% 103 <1%

Procedure type

THR using cement 45,053 48% 42,574 47% 87,627 48%

THR not using cement 21,346 23% 19,201 21% 40,547 22%

Hybrid or reverse hybrid THR 11,446 12% 14,417 16% 25,863 14%

Primary resurfacing 6,723 7% 9,650 11% 16,373 9%

Revision 8,389 9% 5,682 6% 14,071 8%

Provider type

NHS hospital 83,621 90% 31,408 34% 115,029 62%

Independent hospital 3,232 4% 54,480 60% 57,712 31%

NHS Treatment Centre 4,929 5% 2,437 3% 7,366 4%

Independent Treatment Centre 1,175 1% 3,199 3% 4,374 2%

* The non HES-linked procedures exclude those procedures undertaken inWales as these were not linkable to HES (see Section 2.2)


Table 2.3Comparison of patient, procedure and provider type for HES-linked and non HES-linked knee replacement procedures, 1 April 2003 to 30 September 2006*

* The non HES-linked procedures exclude those procedures undertaken inWales as these were not linkable to HES (see Section 2.2)

Linked to a HES episode Not linked to a HES episode Total number of proceduresthat were HES-linkable*

Total 94,263 82,727 176,990


75,600 48,907 124,507

Mean (sd) 70 (10) 69 (11) 70 (10)

Interquartile range 64 - 77 63 - 77 64 - 74

n % n % n %


Male 32,650 43% 21,470 44% 54,120 44%

Female 42,945 57% 27,442 56% 70,387 57%


P1 – Fit and healthy 17,518 19% 22,626 27% 40,144 23%

P2 – Mild disease not incapacitating 61,070 65% 51,348 62% 112,418 64%

P3 – Incapacitating systemic disease

15,062 16% 8,451 10% 23,513 13%

P4 – Life threatening disease 560 1% 270 <1% 830 <1%

P5 – Expected to die within 24hrs 53 <1% 32 <1% 85 <1%

Procedure type

TKR using cement 75,738 80% 61,823 74% 137,561 78%

TKR not using cement 6,517 7% 5,058 6% 11,575 7%

Hybrid or reverse hybrid TKR 1,262 1% 1,228 1% 2,490 1%

Unicondylar knee replacement 4,531 5% 9,455 11% 13,986 8%

Patello-femoral replacement 734 1% 1,152 1% 1,886 1%

Revision 5,481 6% 4,011 5% 9,492 5%

Provider type

NHS hospital 83,232 88% 31,126 38% 114,358 65%

Independent hospital 4,034 4% 45,147 55% 49,181 28%

NHS Treatment Centre 5,802 6% 2,659 3% 8,461 5%

Independent Treatment Centre 1,195 1% 3,795 5% 4,990 3%

Part 23. Overview of Hip and Knee Replacement Procedures, 2006



This summarises the numbers of hip and knee replacementprocedures undertaken in England and Wales between 1 January 2006 and 31 December 2006 and entered into theNJR by 28 February 2007. The procedures are summarisedaccording to the type of hospital or treatment centre, fundingand patient characteristics.

3.1 Hospitals and Treatment CentresParticipating in the NJR

During the 2006 data collection period, 41515 hospitals andtreatment centres (TCs) were open, and of these 393 (95%)submitted at least one hip or knee procedure into the NJR(Table 3.1). The compliance rate of 79% (determined fromthe number of leviable components) was lower than the 95%centre participation rate, indicating that not all procedures atthe participating centres were recorded. On average, 112 hipreplacements and 99 knee replacements were recorded per unit over the year, although the numbers varied from 1 procedure to over 1000 procedures (Table 3.2).

Compared with previous years, there was an overallreduction in the number of centres reporting fewer than 100 procedures in a year and an increase in centresreporting more than 400 procedures in a year (Figure 3.1).

3.2 Hip Replacement Procedures

This section summarises the patient characteristics andprocedure details of hip replacements according to the type of provider (Table 3.2). 93% of patients at independenthospitals and independent sector Treatment Centres,compared with 81% at NHS units, were graded as fit andhealthy or with mild disease according to the AmericanSociety of Anaesthesiologists (ASA) grade system. Nearly all (98%) of procedures undertaken at ISTCs were primaryprocedures and over half of these were cemented procedures.Independent hospitals performed more primary resurfacingprocedures (Figure 3.2) compared with other provider types.There were more revision procedures undertaken at NHShospitals (12%) than at any other type of provider (5% overall).The revision procedures undertaken at NHS hospitals comprise81% of all revision procedures.

Explicit comparisons of patient characteristics for hipreplacement procedures carried out in 2006 with those in2004 and 2005 are reported in Section 4.1.

3.3 Knee Replacement Procedures

Table 3.4 summarises the patient characteristics and proceduredetails of knee replacements according to type of provider.Independent hospitals performed more unicondylar kneereplacement procedures (Figure 3.3) compared with anyother type of provider. As was observed for hip replacementprocedures, there were more revision procedures at NHShospitals (6%) than at any other type of provider (3% overall).The revision procedures undertaken at NHS hospitalscomprised 80% of all revision procedures.

Explicit comparisons of patient characteristics for kneereplacement procedures carried out in 2006 with those in2004 and 2005 are reported in Section 5.1.

15 This is for the calendar year 1 January to 31 January 2006


Num

ber

of h

ospi

tals

140 –

120 –

100 –

80 –

60 –

40 –

20 –

0 –<50 50 - 99 100 - 99 200 - 299 300 - 399 400+

Hip procedures

Number of operations

Num

ber

of h

ospi

tals

140 –

120 –

100 –

80 –

60 –

40 –

20 –

0 –

<50 50 - 99 100 - 99 200 - 299 300 - 399 400+

Knee procedures

Number of operations

2004

2005

2006

2004

2005

2006

Figure 3.1Number of participating hospitals by number of procedures, 2004 - 2006


NHSHospital

NHSTreatment

Centre

IndependentHospital

IndependentTreatment

Centre

Per

cent

age

100% –

90% –

80% –

70% –

60% –

50% –

40% –

30% –

20% –

10% –

0 –

Cemented

Cementless

Hybrid

Resurfacing

NHSHospital

NHSTreatment

Centre

IndependentHospital

IndependentTreatment

Centre

Per

cent

age

100% –

90% –

80% –

70% –

60% –

50% –

40% –

30% –

20% –

10% –

0 –

Hybrid

Cemented

Patello-Femoral

Cementless

Unicondylar

Figure 3.2Primary hip procedures by provider type

Figure 3.3Primary knee procedures by provider type


3 Overview of Hip and Knee Replacement Procedures, 2006

Table 3.1Total number of hospitals and Treatment Centres in England and Wales able to participate in the NJR and proportion actuallyparticipating in 2006

2006 Total (England and Wales)

Participating in the NJR 2006

n %

NHS hospitals 226 208 92%

England 209 191

Wales 17 17

Independent hospitals 167 165 99%

England 161 159

Wales 6 6

NHS Treatment Centres 11 10 91%

England 11 10

Wales 0 0

Independent Treatment Centres 11 10 91%

England 11 10

Wales 0 0

415 393 95%


Table 3.2Number of participating hospitals according to number of procedures entered over the 2006 data collection period

2006 Number of procedures recorded in NJR in 2006

Total numberof hospitals

< 5050

- 99100

- 199200

- 299300

- 399400+

Average numberper unit

Min Max

All Operations

Hospitals entering hip replacements 383 89 83 116 52 21 22 112 1 1,253

Hospitals entering knee replacements 381 99 93 94 38 34 23 99 1 1,388

Primary Operations

Hospitals entering primary hip replacements 382 96 92 108 55 18 13 102 1 1,167

Hospitals entering primary knee replacements 380 102 99 89 41 29 20 95 1 1,352


1 2 - 4 5 - 910

- 1920

- 4950+


Min Max

Revision/Re-operation

Hospitals entering revision/re-operation hip replacements

317 30 68 60 64 67 28 10 1 236

Hospitals entering revision/re-operation knee replacements

303 33 99 65 56 40 10 5 1 116

2005 Number of procedures recorded in NJR in 2005


< 5050

- 99100

- 199200

- 299300

- 399400+


Min Max

All Operations

Hospitals entering hip replacements 386 80 80 115 67 29 15 122 1 1,226

Hospitals entering knee replacements 381 77 81 120 51 31 21 122 1 1,429

Primary Operations

Hospitals entering primary hip replacements 386 87 82 120 67 18 12 111 1 1,037

Hospitals entering primary knee replacements 381 80 82 121 53 25 20 117 1 1,396


1 2 - 4 5 - 910

- 1920

- 4950+


Min Max

Revision/Re-operation

Hospitals entering revision/re-operation hip replacements

318 30 79 55 63 63 28 9 1 224

Hospitals entering revision/re-operation knee replacements

302 50 89 66 51 40 6 5 1 115


Table 3.3Patient characteristics and procedure details according to type of provider for hip procedures in 2006

2006 Provider type

NHS hospitals Independenthospitals

NHS TreatmentCentres

IndependentTreatment Centres

Total

n % n % n % n % n %

Total 39,924 n/a 15,585 n/a 3,343 n/a 2,604 n/a 61,456 n/a


P1 – Fit and healthy 7,244 18% 5,062 32% 791 24% 592 23% 13,689 22%

P2 – Mild disease, not incapacitating 24,992 63% 9,344 60% 2,155 64% 1,896 73% 38,387 62%

P3 – Incapacitating systemic disease 7,289 18% 1,119 7% 382 11% 113 4% 8,903 14%

P4 – Life threatening disease 370 1% 49 0% 13 0% 2 0% 434 1%

P5 – Not expected to survive 24 hours 29 0% 11 0% 2 0% 1 0% 43 0%

Procedure type

Primary procedure 34,985 88% 14,694 94% 3,117 93% 2,556 98% 55,352 90%

Total hip replacement using cement 16,585 47% 6,101 42% 1,141 37% 1,486 58% 25,313 46%

Total hip replacement not using cement 9,961 28% 4,375 30% 1,217 39% 863 34% 16,416 30%

Hybrid or reverse hybrid total replacement 5,372 15% 2,001 14% 468 15% 186 7% 8,027 14%

Primary resurfacing 3,067 9% 2,217 15% 291 9% 21 1% 5,596 10%

Revision procedure 4687 12% 872 6% 223 7% 39 1% 5,821 9%

Hip Single Stage Revision 3931 84% 781 90% 210 94 31 79% 4,953 85%

Hip Revision (Stage 1 of 2) 306 7% 32 4% 3 1% 2 5% 343 6%

Hip Revision (Stage 2 of 2) 396 8% 56 6% 9 4% 5 13% 466 8%

Hip Girdlestone 54 1% 3 0% 1 0% 1 3% 59 1%

Re-operation other than revision 252 1% 19 0% 3 0% 9 0% 283 0%

Bilateral or unilateral

Bilateral 100 0% 164 1% 2 0% 2 0% 268 0%

Unilateral 39,824 100% 15,421 99% 3,341 100% 2,602 100% 61,183 100%

Primary procedure complexity**

Hip primary 33,146 83% 14,260 91% 2,983 89% 2,518 97% 52,902 86%

Hip complex primary 1,839 5% 434 3% 134 4% 38 1% 2,445 4%

Funding**

NHS funding 32,911 96% 2,772 21% 2,957 99% 2,470 100% 41,110 78%

Independent funding 1,212 4% 10,163 79% 25 1% 0 0% 11,395 22%

Not recorded 5,801 n/a 2,650 n/a 361 n/a 134 n/a 8,946 n/a

** Optional field


Table 3.4Patient characteristics and procedure details according to type of provider for knee procedures in 2006

2006 Provider type

NHS hospitals Independenthospitals

NHS TreatmentCentres

Independent Treatment Centres

Total

n % n % n % n % n %



P1 – Fit and healthy 5,987 15% 3,321 25% 590 15% 617 21% 10,515 17%

P2 – Mild disease, not incapacitating 27,441 67% 8,643 66% 2,920 73% 2,243 75% 41,247 68%

P3 – Incapacitating systemic disease 7,271 18% 1,024 8% 475 12% 129 4% 8,899 15%


P5 – Not expected to survive 24 hours 26 0% 10 0% 3 0% 0 0% 39 0%

Procedure type

Primary procedure 38,245 93% 12,495 96% 3,909 98% 2,948 99% 57,597 94%

Total knee replacement using cement 32,096 84% 9,502 76% 3,287 84% 2,741 93% 47,626 83%

Total knee replacement not using cement 2,542 7% 1,035 8% 378 10% 133 5% 4,088 7%

Hybrid total replacement 356 1% 271 2% 70 2% 5 0% 702 1%

Unicondylar knee replacement 2,846 7% 1,475 12% 150 4% 62 2% 4,533 8%

Patello-femoral replacement 405 1% 212 2% 24 1% 7 0% 648 1%

Revision procedure 2,445 6% 497 4% 84 2% 22 1% 3,048 5%

Single Stage Revision 1,763 72% 394 79% 68 81% 17 77% 2,242 74%

Revision (Stage 1 of 2) 310 13% 40 8% 6 7% 3 14% 359 12%

Revision (Stage 2 of 2) 359 15% 60 12% 10 12% 2 9% 431 14%

Amputation 2 0% 1 0% 0 0% 0 0% 3 0%

Conversion to arthrodesis 11 0% 2 0% 0 0% 0 0% 13 0%

Re-operation other than revision 274 1% 38 0% 9 0% 0 0% 321 1%

Bilateral or unilateral

Bilateral 266 1% 350 3% 0 0% 2 0% 618 1%

Unilateral 40,698 99% 12,680 97% 4,002 100% 2,988 100% 60,368 99%

Primary procedure complexity**

Knee primary 36,923 90% 12,220 94% 3,822 96% 2,927 98% 55,893 92%

Knee complex primary 1,322 3% 271 2% 87 2% 21 1% 1,701 3%

Funding**

NHS funding 33,853 98% 3,507 33% 3,594 100% 2,826 100% 43,780 85%

Independent funding 623 2% 7,193 67% 12 0% 0 0% 7,828 15%


** Optional field

Part 24. Hip Replacement Procedures



4.1 Hip Replacement Procedures, 2006

This section summarises the patient characteristics andsurgical details of all 55,352 primary, 5,821 revision and 283 re-operation hip replacement procedures undertakenbetween 1 January and 31 December 2006 and entered intothe NJR by 28 February 2007. Fields for which data entry isoptional are indicated in the tables of results. All optionalfields, apart from “untoward intra-operative events”, werereported in more than 80% of procedures.

4.1.1 Primary hip replacement procedures, 2006

Almost half of the 55,352 primary hip replacementprocedures undertaken in 2006 were cemented total hipreplacements (THR) and 5,596 (10%) were hip resurfacingprocedures (Table 4.1).

Compared with previous years, there has been a reduction inthe use of cemented THR procedures and hybrid or reversehybrid procedures and a corresponding increase in the useof cementless procedures (Figure 4.1). The greatest changeswere a reduction in cemented procedures from 53% during2004 to 48% during 2006, and an increase in cementlessprocedures from 21% during 2004 to 30% during 2006.

4.1.1.1 Patient characteristics

Age and gender were recorded only for those patients whogave consent (82%) for their personal identifiers to be enteredinto the NJR. The average age was 68 years and about 60%of the patients were female (Table 4.1). On average, femalepatients were older than male patients at the time of theirprimary hip replacement (69 years vs 66 years respectively,Table 4.2). Patients undergoing a resurfacing procedure werethe youngest at an average age of 55 years (See Figure 4.2).

Per

cent

age

60% –

50% –

40% –

30% –

20% –

10% –

0 –

THR using cement

THR not using cement

Hybrid or reverse hybrid THR

Hip resurfacing

2004

Q1

2004

Q2

2004

Q3

2004

Q4

2005

Q1

2005

Q2

2005

Q3

2005

Q4

2006

Q1

2006

Q2

2006

Q3

2006

Q4

Figure 4.1Type of primary hip replacementprocedure undertaken between2004 and 2006


According to the American Society of Anaesthesiologists(ASA) grade system, about a quarter of patients undergoinga primary hip replacement in 2006 were graded as being “fit and healthy” prior to surgery. The single largest indicationrecorded for surgery was osteoarthritis, recorded in 94% ofprocedures.

Compared to previous years, the patient characteristicsdescribed above have largely remained unchanged.However, there has been an increase in hip operations inpatients with mild or incapacitating disease. For example,procedures in patients with mild disease increased from 57%in 2004 to 63% in 2006.

4.1.1.2 Surgical techniques

The surgical techniques used in procedures undertaken in 2006are summarised in Table 4.3. Patients were mainly positionedlaterally. The lateral position was used more frequently inhybrid and resurfacing procedures than in cemented andcementless procedures. The most frequently used incisionapproach was posterior for cementless, hybrid and resurfacingprocedures and lateral for cemented procedures. Use ofminimally invasive surgery (MIS) was greatest in cementlessprocedures, although it was used in less than a tenth of all procedures.

Compared with previous years, there has been an increasein the use of a lateral patient position, a posterior incisionapproach and a reduction in the use of cemented prostheses.The use of a lateral patient position increased from 83% in2004 to 88% in 2006, while the use of a posterior incisionapproach increased from 39% in 2004 to 46% in 2006. Thereduction in the use of cemented stems from 77% in 2004 to69% in 2006 and from 56% to 47% in the use of cementedcups is consistent with the reduction seen in the overallnumber of cemented procedures (Figure 4.1).

4.1.1.3 Thromboprophylaxis

The most frequently prescribed chemical method was lowmolecular weight heparin, and TED stockings were the mostfrequently prescribed mechanical method (Table 4.4). Eachof these methods was prescribed for use after about 60% ofall procedures.

There has been an increase in procedures in which bothchemical and mechanical methods are prescribed from 50%in 2004 to 61% in 2006. The increase can partly be attributedto similar changes in the prescription of low molecularweight heparin, which increased from 50% to 60%, and TEDstockings which increased from 53% to 61%. A marginalincrease was also seen in the prescription of a foot pumpfrom 24% in 2004 to 28% in 2006.

Cemented THR

Uncemented THR

HybridTHR

HipResurfacing

Per

cent

age

<55 years

55-64 years

65-74 years

>75 years

60% –

50% –

40% –

30% –

20% –

10% –

0 –

Female Figure 4.2Age and gender for primary hip replacementpatients in 2006


4.1.1.4 Untoward intra-operative events

Untoward intra-operative events were reported in 1% ofprocedures (Table 4.5). Completion of the data field requestingthese events was not mandatory and the default option,which held when the field was not completed, was that nountoward intra-operative event occurred. Of the 625 untowardevents reported, about a third were calcar cracks. Comparedwith previous years, the pattern of untoward intra-operativeevents has largely remained the same.

4.1.2 Hip revisions, 2006

A total of 5,821 hip revision procedures were reported. Thisincludes 466 (8%) procedures that were Stage 2 of a two-stagerevision process and which have been excluded from the restof the section. Of the remaining 5,355 procedures (Table 4.6),4,953 (93%) were single stage revision procedures, 343 (6%) were Stage 1 of a two-stage process and 59 (1%) wereGirdlestone type procedures. Compared with previous years,there has been no change in the types of revision procedurescarried out.


Table 4.6 summarises patient characteristics for the 5,355 hip revision procedures (excluding Stage 2 procedures)undertaken in 2006. Compared with previous years, the patientcharacteristics shown in Table 4.6 have largely remainedunchanged. However, changes were seen in the generalmedical condition of patients and indications for revision.

There was a reduction in patients who were fit and healthyprior to surgery, with a corresponding increase in patientswith mild or incapacitating disease. For example, proceduresin patients with mild disease increased from 57% in 2004 to 59% in 2006. A similar pattern was seen in primary hipreplacement procedures. With regard to the indication forsurgery among two-stage revision procedures (Table 4.7),there was, for example, a reduction in revision for asepticloosening from 44% in 2004 to 22% in 2006.

Cemented THR

Uncemented THR

HybridTHR

HipResurfacing

Per

cent

age

<55 years

55-64 years

65-74 years

>75 years

60% –

50% –

40% –

30% –

20% –

10% –

0 –

Male Figure 4.2 (continued)Age and gender for primary hip replacementpatients in 2006


4.1.2.2 Components removed and components used

Both the acetabular and femoral components were removedin over half of all revision procedures (Table 4.8). However,comparing the different types of revision proceduresindicates that both components were more likely to beremoved during a two-stage revision process or with a hipGirdlestone type procedure than during a single stagerevision. About a third of the femoral or acetabularcomponents used during single stage revision procedureswere cemented (Table 4.9).

4.1.3 Hip re-operations other than revision, 2006

A total of 341 re-operation procedures following an initial hipreplacement were recorded. Of all re-operations, 15% involvedsocket augmentation and 15% were reported as woundexploration (Table 4.10). 60% of the re-operations had otherdescriptions outside of the list of options given and includedclosed reduction of dislocation, exchange of femoral headand application of a posterior lipped augmentation device(PLAD) used in socket augmentation.

The characteristics of patients undergoing a hip re-operation in2006 are shown in Table 4.11. The average age of the patientswas 71 years and over half of the patients were female(58%). A physical status of ‘fit and healthy’ or ‘mild disease,not incapacitating’ was declared for 68% of hip patients.

4.2 Outcomes Following Primary HipReplacement, 2003 – 2006

This section presents analyses of revision and mortality rates aswell as length of stay for primary hip replacement procedures,with special attention given to revision of hip resurfacingprocedures. The analyses are based on data on hip replacementprocedures undertaken between 1 April 2003 and 30 September2006 that were linked to an episode in the HES database. As explained in Section 2.2, the linked procedures werethose undertaken in England, and mainly in NHS hospitals.A description of the linkage process, as well as the patientcharacteristics of the linked procedures in also included inSection 2.2.

4.2.1 Revision

This section summarises survival to revision of implants usedin primary hip replacement procedures that were linked to aHES procedure. All 76,576 primary hip replacement proceduresin the NJR that were undertaken between 1 April 2003 and30 September 2006 and linked to a HES episode that wasalso defined as a primary hip replacement procedure wereidentified. Of the linked primary hip replacement procedures,72,534 (95%) were undertaken at NHS hospitals and NHStreatment centres and 4,042 (5%) were undertaken in theindependent sector.

In HES, primary hip replacements for the patients with linked procedures were identified using the following OPCS-416 procedure codes:

W371 – Primary total prosthetic replacement of hip jointusing cement

W381 – Primary total prosthetic replacement of hip joint notusing cement

W391 – Primary total prosthetic replacement of hip joint notelsewhere classified

W581 – Primary resurfacing arthroplasty of joint

Some patients had two primary hip replacement procedures,one on each side, which occurred on different dates and wereboth linked to a HES record. In such cases, to avoid includinga patient twice in the linked database, only the earliest primaryprocedure was retained. For each patient with a linkedprimary procedure, all hospital episodes recorded in HESsucceeding the primary procedure were identified. From thesesucceeding episodes, the first hip revision that occurred onthe same side as the primary was then identified in HES.Where the side of the primary or the revision was not recorded,the first revision that occurred after the primary procedure wasassumed to be a revision of that primary. In HES, revisionprocedures were identified using the procedure codesW373, W383, W393 and W582 (with Z843 – hip joint) indicatingrevision of a cemented, cementless, unclassified and hipresurfacing primary procedure, respectively. In addition, revisioncodes indicating conversion from one type of replacement toanother, as well as attention to the replacement joint in whichthere was renewal of the prosthesis, were also identified asrevisions. Codes indicating other types of attention to the hipreplacement joint, such as correction of displacement ofprosthesis, were considered to be re-operations and werenot included.

Using the revisions identified in HES as described above, revisionrates were then estimated for various patient characteristics,as well as procedure and provider types. The revision rateswere estimated using the Kaplan-Meier survival analysismethod that allows prostheses that are followed up forunequal lengths of time after implant to be included.

16 Office of Population, Censuses and Surveys: Classification of SurgicalOperations and Procedures, 4th Revision


4.2.1.1 Procedure type

The overall revision rate following primary hip replacementwas 0.7% (95% CI 0.6% – 0.7%) at 1 year and 1.3% (95% CI1.2% – 1.5%) at 3 years. Figure 4.3 shows estimates ofimplant survival to revision by procedure type, together withrevision rates at 3 months, 1 year and 3 years followingprimary hip replacement.

Resurfacing procedures have a statistically significantly higherrate of revision compared to THR procedures, a difference thatis already apparent within the first 3 months after replacement.Analyses of longer term survival, which has not been possiblein this Report on account of the limited follow-up time allowedby the NJR, is necessary to establish the comparativeperformance of hip resurfacing in the long term.

Procedures type (n) 3 months

0.2% (0.1% – 0.2%)

0.5% (0.5% – 0.7%)

0.3% (0.2% – 0.4%)

0.9% (0.7% – 1.2%)

Cemented (41,232)

Cementless (19,022)

Hybrid (10,120)

Resurfacing (6,202)

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

Cemented THR

Hybrid THR

Cementless THR

Hip Resurfacing

1 year

0.3% (0.3% – 0.4%)

1.0% (0.8% – 1.1%)

0.7% (0.5% – 0.9%)

1.6% (1.3% – 2.0%)

3 years

0.9% (0.7% – 1.1%)

1.9% (1.6% – 2.3%)

1.4% (1.1% – 1.9%)

2.4% (2.0% – 3.0%)

0 1 2 3

Analysis time (years from operation)

Revision rate (95% Cl)

Figure 4.3Revision rate estimates forHES-linked primary hipreplacement procedures, 2003 – 2006


4.2.1.2 Age and gender

A difference in age and gender distribution was foundamong primary hip replacement procedures undertaken in2006 (Section 4.1.1). The influence of these two factors onrevision rates following primary hip replacement is exploredin this section.

Figure 4.4 shows revision rates for patients aged less than55 years and those aged 55 or older, separately. The onlyage-related difference in revision rates was observed inpatients who underwent hip resurfacing. In these patients,the revision rate was higher in patients aged 55 and overand this difference was pronounced in the early post-operative period. Figure 4.5 shows revision rates for femaleand male patients separately. The revision rate for hipresurfacing procedures was statistically significantly higherthan that for other procedure types among female patients.

Table 4.12 shows the results of a multivariable analysis inwhich the impact of patient age, gender and physical status,as well as procedure and provider type on 1-year revisionrates was assessed. The crude rate is not adjusted for otherfactors. For example, the crude revision rates shown for theprocedure types do not take into account that patientsundergoing hip resurfacing are on average younger thanthose undergoing other types of procedures. A multivariablemodel can be used to adjust simultaneously for important

confounding factors, such as age and gender, when comparingrates for different procedure types. The hazard ratio for agiven factor level in Table 4.12 is a ratio of the risk of revisionwithin 1 year after replacement among those implants thathave not yet failed, relative to the risk for the reference level(shown by a hazard ratio of 1) of that factor. For example,the hazard ratio shown for hip resurfacing compares the risk of revision within 1 year for a patient who undergoes aresurfacing procedure relative to that of another patient ofthe same age, gender and physical status who undergoes a cemented procedure. Likewise, the hazard ratio shown for hybrid hip replacements compares the risk of revision for hybrid procedures relative to cemented procedures.

The hazard ratios presented in Table 4.12 suggest thatprocedure type is the most influential factor on implantsurvival following primary hip replacement. Hip resurfacingprocedures have statistically significantly higher revision ratesthan cemented THR procedures, after adjusting for age,gender, ASA grade and provider type. The results shown inFigures 4.4 and 4.5 suggest that a large number of thefailures in hip resurfacing procedures contributing to theirrelatively higher revision rate occur in older female patients.

0 1 2 3

0.4% (0.2% - 0.9%)

0.7% (0.4% - 1.1%)

0.6% (0.3% - 1.3%)

1.2% (0.9% - 1.7%)

Cemented THR

Cementless THR

Hybrid THR

Hip resurfacing

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

Cemented THR

Hybrid THR

Cementless THR

Hip Resurfacing


1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –0 1 2 3


Age <55 years Age 55+ years

1 year revision rates (95% Cl) [n=8,982]

0.3% (0.3% - 0.4%)

1.0% (0.9% - 1.2%)

0.7% (0.5% - 0.9%)

2.0% (1.6% - 1.7%)

Cemented THR

Cementless THR

Hybrid THR

Hip resurfacing


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Figure 4.4Revision rate estimates by age for HES-linked primary hip replacement procedures,2003 – 2006


4.2.1.3 Comparison of revision rates with other national registries

A comparison of revision rates seen in the NJR with thosereported in other national registries showed that the ratesreported in the NJR were generally lower than those reportedelsewhere17,18,19. However, there were differences in thedefinition of what a revision is across registries, with someregistries including re-operations as revisions. Furthermore,revisions were specified for different time periods and it hasbeen shown in that revision rates have improved significantlyover time.

4.2.1.4 Revision rates for the most frequently used implant brands

Figures 4.6 and 4.7 show revision rates for cemented andcementless stems, respectively for the most frequently usedbrands. There were no statistically significant differencesamong the different brands of stems.

0 1 2 3

0.3% (0.3% - 0.4%)

1.1% (0.9% - 1.3%)

0.6% (0.5% - 0.9%)

2.1% (1.5% - 2.8%)

Cemented THR

Cementless THR

Hybrid THR

Hip resurfacing

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

Cemented THR

Hybrid THR

Cementless THR

Hip Resurfacing


1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –0 1 2 3


Female Male


0.6% (0.5% - 0.7%)

1.1% (0.9% - 1.4%)

0.9% (0.7% - 1.3%)

1.6% (1.2% - 2.1%)

Cemented THR

Cementless THR

Hybrid THR

Hip resurfacing


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Figure 4.5Revision rate estimates formale and female patients with HES-linked primary hipreplacement procedures

17 Australian Orthopaedic Association National Joint Replacement RegistryAnnual Report 2006. https://www.dmac.adelaide.edu.au/aoanjrr/documents/aoanjrrreport_2006.pdf

18 The Norwegian Arthroplasty Register, 2006. http://www.haukeland.no/nrl/

19 The Swedish Hip Arthroplasty Register Annual Report 2005http://www.jru.orthop.gu.se/


Brand (n) 3 months

0.1% (0.06% - 0.3%)

0.1% (0.06% - 0.2%)

0.3% (0.1% - 0.5%)

0.2% (0.1% - 0.2%)

0.2% (0.07% - 0.6%)

C-Stem (4,826)

Charnley (7,835)

CPT (3,081)

Exeter (23,725)

Stanmore Modular (1,260)

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

1 year

0.4% (0.3% - 0.7%)

0.3% (0.2% - 0.4%)

0.7% (0.4% - 1.1%)

0.4% (0.3% - 0.5%)

0.3% (0.1% - 0.8%)

3 years

1.2% (0.8% - 1.8%)

0.8% (0.6% - 1.2%)

1.0% (0.7% - 1.6%)

0.8% (0.6% - 1.1%)

1.3% (0.4% - 4.3%)

0 1 2 3



C-Stem

Exeter

Charnley

Stanmore Modular

CPT

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Figure 4.6Revision rate estimates for the five most commonly usedhip cemented stem brands,2003 – 2006

Brand (n) 3 months

0.9% (0.5% - 1.7%)

0.3% (0.2% - 0.5%)

0.6% (0.4% - 0.8%)

ABG II (1,091)

Corail (5,230)

Furlong (5,927)

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

Corail

Furlong HAC

ABG II

1 year

1.2% (0.7% - 2.1%)

0.6% (0.4% - 0.9%)

1.1% (0.9% - 1.5%)

3 years

1.6% (0.9% - 2.7%)

1.2% (0.8% - 1.9%)

2.2% (1.7% - 2.8%)

0 1 2 3



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Figure 4.7Revision rate estimates for the three most commonlyused hip cementless stembrands, 2003 – 2006

Brand (n) 3 months

0.06% (0.02% - 0.2%)

0.1% (0.05% - 0.3%)

0.2% (0.2% - 0.4%)

0.08% (0.03% - 0.2%)

0.3% (0.1% - 0.5%)

Charnley (5,010)

Charnley Ogee (3,921)

Contemporary (6,424)

Eliet Plus Ogee (6,013)

Exeter Duration (3,712)

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

1 year

0.2% (0.1% - 0.4%)

0.4% (0.2% - 0.6%)

0.4% (0.2% - 0.6%)

0.3% (0.2% - 0.4%)

0.5% (0.3% - 0.8%)

3 years

0.8% (0.5% -1.3%)

0.9% (0.6% -1.4%)

0.9% (0.6% -1.5%)

1.0% (0.6% -1.6%)

1.3% (0.7% - 2.3%)

0 1 2 3



Charnley

Contemporary

Exeter Duration

Charnley Ogee

Elite Plus Ogee

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Figure 4.8Revision rate estimates for the five most commonly usedhip cemented cup brands,2003 – 2006


4.2.2 Resurfacing procedures

This section presents results of detailed analyses of hipresurfacing procedures, focusing on revision rates for themost commonly used brand, the causes of failure comparedwith other types of primary hip replacement, as well asrevision of procedures where a large modular head wasused with a regular stem and a resurfacing cup.

Figure 4.10 shows revision rates for the Birmingham HipResurfacing (BHR) prosthesis, which is the most frequentlyused brand. There were insufficient procedures performed toallow reliable estimates of revision rates to be obtained forother brands of hip resurfacing prostheses.

4.2.2.1 Causes of failure

Figure 4.3 showed that hip resurfacing procedures have ahigher rate of revision, particularly in the early post-operativeperiod. The causes of failure for the different primary proceduretypes are shown in Table 4.13. The cause of failure for eachprimary procedure was determined from the indication forsurgery for the corresponding revision procedure. The mostcommon causes of failure for hip resurfacing procedureswere peri-prosthetic fractures and pain. In comparison, themost common causes of failure for cemented THR procedureswere aseptic loosening and infection.

4.2.2.2 Use of large modular heads with regular stems andresurfacing cups

Recent trends (see Section 6.1.4) show an increase in theuse of a resurfacing cup with a conventional stem and alarge metal-on-metal modular femoral head. However, thenumber of procedures carried out is insufficient to allow areliable estimation of revision rates to be made.

Brand (n) 3 months

0.6% (0.4% - 0.8%)

0.5% (0.3% - 0.8%)

0.6% (0.4% - 0.9%)

CSF (5,692)

Duraloc (2,991)

Trilogy (4,104)

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

1 year

1.1% (0.8% - 1.4%)

0.8% (0.5% - 1.2%)

1.1% (0.8% - 1.4%)

3 years

2.1% (1.6% - 2.7%)

1.6% (1.1% - 2.3%)

1.5% (1.1% - 2.1%)

0 1 2 3



CSF

Duraloc

Trilogy

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Figure 4.9Revision rate estimates forthe three most commonlyused hip cementless cupbrands, 2003 – 2006


4.2.3 Mortality

This section summarises mortality rates for primary hipreplacement patients for all 76,317 procedures undertakenbetween 1 April 2003 and 30 June 2006 that were linked to aHES record. At the time of analysis, dates of death were onlyavailable up to 30 June 2006 and only those proceduresundertaken up to this date could therefore be analysed.

The mortality rate of primary hip replacement patients was1.9% (95% CI 1.8% - 2.0%) at 1 year and 5.0% (95% CI 4.7%- 5.3%) at 3 years. Mortality rates at 1 year following primaryhip replacement were compared with that of the generalpopulation of England and Wales, using age and genderadjusted standardised mortality ratio (SMR) (Table 4.14). The comparison showed that mortality among hipreplacement patients is less than half of that observed in ageneral age-matched and sex-matched population, with theoverall SMR (comparison of observed and expected deaths)being 0.46 (95% CI 0.43-0.49).

Table 4.15 shows the results of a multivariable analysis ofmortality at 1 year (see Section 4.2.1 for an explanation ofmultivariable analyses and hazard ratios). After adjusting forconfounding factors, mortality at 1 year remains higher forolder patients and those in a poor general medical condition,but lower for female than male patients. Mortality at 1 yearfollowing primary hip resurfacing is lower than that followingcemented total hip replacement after adjusting for age, genderand patient physical status. However, most patients undergoinghip resurfacing are under 65 years of age and are graded asfit and healthy (see Tables 4.1 and 4.2), which complicatesinterpretation of the results.

Brand (n) 1 year

1.2% (0.9% - 1.6%)BHR (4,148)

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

2 years

1.6% (1.3% - 2.2%)

3 years

1.8% (1.4% - 2.4%)

0 1 2 3



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Figure 4.10Revision rate estimates for the most commonly usedbrand of hip resurfacingprostheses, 2003 – 2006



Mortality rates up to 1 year following primary hip replacementwere compared between patients with different types ofthromboprophylaxis prescribed at the time of surgery, includingthose for whom none was prescribed. There were nostatistically significant differences in mortality between thedifferent types prescribed (Figure 4.11).

4.2.4 Length of stay

This section presents results for the analysis of length ofhospital stay following admission for a primary hipreplacement procedure among procedures linked to a HESepisode. Table 4.16 gives the average length of stay forpatients with particular characteristics, as well as byprocedure and provider type. The average length of staywas calculated as the total number of bed days divided bythe number of patients.

The average length of stay following primary hip replacementwas 9.1 days. Length of stay is influenced by several factors,including those shown in Table 4.16. Valid comparison oflength of stay across procedure type requires adjustment fordifferences in patient characteristics. For example, patientswho undergo hip resurfacing procedures are on averageyounger than those who undergo total hip replacement, andthis difference in average age should be taken into account

3 months

0.7% (0.4% - 1.3%)

0.7% (0.6% - 0.9%)

0.8% (0.6% - 1.0%)

0.7% (0.6% - 0.8%)

None prescribed[n=1,446]

Chemical only [n=19,484]

Mechanical only [n=13,183]

Both types[n=42,204]

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

6 months

1.1% (0.6% - 1.7%)

1.2% (1.0% - 1.3%)

1.2% (1.0% - 1.4%)

1.1% (1.0% - 1.2%)

1 year

1.9% (1.3% - 2.8%)

1.9% (1.7% - 2.1%)

2.0% (1.8% - 2.3%)

1.8% (1.7% - 2.0%)

0 3 6 129

Analysis time (months from operation)

Mortality rate (95% Cl)

None prescribed

Mechanical only

Chemical only

Both types

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Figure 4.11Mortality for patients with and those without anythromboprophylaxisprescribed at the time ofprimary hip replacement, 2003 – 2006


in comparing the length of stay across different proceduretypes. The difference in average length of stay shown foreach factor in Table 4.16 is adjusted for the other factors inthe table. Patients who underwent a primary hip resurfacingprocedure stayed in hospital an average 6.3 days, comparedwith 9.7 days following a cemented THR – a difference ofabout 3 days. The adjusted difference between hip resurfacingand cemented THR procedures in the average length of staywas 1 day. The smaller difference seen after adjustmentsuggests that differences in length of stay between proceduretypes are, at least in part, related to patient characteristicsand provider types.

The average length of stay is also shown separately for maleand female patients and in terms of whether they were younger(< 55 years) and older (> 55 years) (Table 4.17). Across thefour groups, older patients stayed, on average, 2 days longerthan younger patients, while female patients stayed, on average,1 day longer than male patients.


4 Hip Replacement Procedures

Table 4.1Patient characteristics for primary hip replacement procedures in 2006, according to type of procedure

2006 Patient procedure

Totalreplacementusing cement

Totalreplacement not

using cement

Hybrid or reversehybrid totalreplacement

Primaryresurfacing

Total

Total 25,313 16,416 8,027 5,596 55,352

Age, years (consenting patients only) n* 20,720 13,588 6,578 4,539 45,425

Mean (sd) 73 (9) 65 (11) 68 (11) 55 (9) 68 (11)

Interquartile range 68 - 79 59 - 72 62 - 76 50 - 61 61 - 76

n % n % n % n % n %

Gender (consenting patients only) n* 20,776 n/a 13,611 n/a 6,587 n/a 4,552 n/a 45,526 n/a

Female 13,677 66% 7,742 57% 4,097 62% 1,634 36% 27,150 60%

Male 7,099 34% 5,869 43% 2,490 38% 2,918 64% 18,376 40%


P1 – Fit and healthy 4,020 16% 4,366 27% 1,609 20% 2,818 50% 12,813 23%

P2 – Mild disease not incapacitating 17,000 67% 9,968 61% 5,264 66% 2,577 46% 34,809 63%

P3 – Incapacitating systemic disease 4,083 16% 1,985 12% 1,096 14% 188 3% 7,352 13%


P5 – Expected to die within 24hrs 8 0% 15 0% 6 0% 3 0% 32 0%

Indications for surgery**

Osteoarthritis 23,920 94% 15,294 93% 7,387 92% 5,380 96% 51,981 94%

Ankylosing spondylitis 73 0% 71 0% 14 0% 21 0% 179 0%

Avascular necrosis 654 3% 559 3% 284 4% 128 2% 1,625 3%

Congenital dislocation/dysplasia of hip 136 1% 339 2% 167 2% 168 3% 810 1%

Failed hemi-arthroplasty 74 0% 31 0% 26 0% 0 0% 131 0%

Failed internal fixation 187 1% 155 1% 89 1% 5 0% 436 1%

Fractured acetabulum 43 0% 42 0% 39 0% 17 0% 141 0%

Fractured neck of femur 397 2% 241 1% 139 2% 3 0% 780 1%

Other hip trauma 24 0% 51 0% 12 0% 16 0% 103 0%

Other inflammatory arthropathy 107 0% 79 0% 52 1% 13 0% 251 0%

Perthes 18 0% 58 0% 26 26% 19 0% 121 0%

Previous arthrodesis 6 0% 8 0% 8 0% 0 0% 22 0%

Infection 14 0% 19 0% 11 0% 5 0% 49 0%

Psoriatic arthropathy 10 0% 14 0% 7 0% 1 0% 32 0%

Seropositive rheumatoid arthritis 233 1% 100 1% 74 1% 14 0% 421 1%

Slipped upper femoral epiphesis 22 0% 71 0% 42 1% 52 1% 187 0%

Other 319 1% 163 163% 106 1% 69 1% 657 1%

Side

Bilateral 48 0% 130 1% 26 0% 64 1% 268 0%

Left, unilateral 11,304 45% 7,527 46% 3,646 45% 2,590 46% 25,067 45%

Right, unilateral 13,961 55% 8,759 53% 4,355 54% 2,942 53% 30,017 54%

* Age and gender reported for consenting patients only (82% of primary procedures)

** More than one indication may be recorded


Table 4.2Age and gender for primary hip replacements in 2006




using cement


Primaryresurfacing

Overall

Average age by gender*

Female n 13,643 n/a 7,729 n/a 4,090 n/a 1,628 n/a 27,090 n/a

Mean (sd), interquartile range 73 (9) 68 - 80 66 (11) 59 - 73 69 (11) 62 - 77 54 (9) 49 - 60 69 (11) 62 - 77

Male n 7,076 n/a 5,859 n/a 2,488 n/a 2,910 n/a 18,333 n/a

Mean (sd), interquartile range 72 (9) 67 - 78 64 (11) 59 - 72 67 (11) 61 - 75 56 (9) 51 - 62 66 (11) 60 - 74

Age group by gender* n % n % n % n % n %

Female

< 45 years 116 1% 306 4% 96 2% 226 14% 744 3%

45 - 54 years 283 2% 804 10% 296 7% 576 35% 1,959 7%

55 - 64 years 1,768 13% 2,473 32% 965 24% 699 43% 5,905 22%

65 - 74 years 5,094 37% 2,672 35% 1,483 36% 113 7% 9,362 35%

75 - 84 years 5,359 39% 1,290 17% 1,038 25% 12 1% 7,699 28%

> 85 years 1,023 8% 184 2% 212 5% 2 <1% 1,421 5%

Male

< 45 years 100 1% 326 6% 87 4% 345 12% 858 5%

45 - 54 years 206 3% 620 11% 203 8% 844 29% 1,873 10%

55 - 64 years 1,086 15% 1,905 33% 625 25% 1,342 46% 4,958 27%

65 - 74 years 3,019 43% 2,178 37% 955 38% 357 12% 6,509 36%

75 - 84 years 2,307 33% 733 13% 529 21% 19 1% 3,588 20%

> 85 years 358 5% 97 2% 89 4% 3 <1% 547 3%



Table 4.3Characteristics of surgical practice for primary hip replacement procedures in 2006, according to type of procedure




using cement


Primaryresurfacing

Total


Laminar flow theatre**

Yes 21,238 98% 14,027 98% 6,976 98% 4,701 98% 46,942 98%

No 478 2% 333 2% 169 2% 110 2% 1,090 2%


n % n % n % n % n %

Patient position

Lateral 21,097 83% 14,327 87% 7,607 95% 5,425 97% 48,456 88%

Supine 4,216 17% 2,089 13% 420 5% 171 3% 6,896 12%

Incision

Anterior/Antero-lateral 4,392 17% 3,159 19% 1,022 13% 441 8% 9,014 16%

Lateral (inc Hardinge) 11,592 46% 5,735 35% 2,519 31% 894 16% 20,740 37%

Posterior 9,329 37% 7,522 46% 4,486 56% 4,261 76% 25,598 46%

Trochanteric osteotomy

Yes 1,140 5% 242 1% 87 1% 122 2% 1,591 3%

No 24,173 95% 16,174 99% 7,940 99% 5,474 98% 53,761 97%

Complex osteotomy

Yes 259 1% 52 0% 9 0% 30 1% 350 1%

No 25,054 99% 16,364 100% 8,018 100% 5,566 99% 55,002 99%

Minimally invasive surgery**

Yes 924 4% 1,619 11% 386 5% 264 5% 3,193 6%

No 22,015 96% 12,855 89% 7,088 95% 4,633 95% 46,591 94%


Incision length**

Greater than 10cm 19,050 89% 10,857 80% 6,323 89% 4,453 95% 40,683 87%

Up to 10cm 2,308 11% 2,753 20% 742 11% 215 5% 6,018 13%


Image guided surgery**

Yes 94 0% 107 1% 31 0% 57 1% 289 1%

No 22,262 100% 13,955 99% 7,244 100% 4,653 99% 48,114 99%



Table 4.3 (continued)




using cement


Primaryresurfacing

Total


n % n % n % n % n %

Femoral bonegraft used**

Yes 100 0% 141 1% 18 0% 33 1% 292 1%

No 25,213 100% 16,275 99% 8,009 100% 5,563 99% 55,060 99%

Acetabular bonegraft used**

Yes 644 3% 701 4% 479 6% 158 3% 1,982 4%

No 24,669 97% 15,715 96% 7,548 94% 5,438 97% 53,370 96%

Femoral cement used

Yes 25,313 100% 0 0% 7,646 95% 4,986 89% 37,945 69%

No 0 0% 16,416 100% 381 5% 610 11% 17,407 31%

Acetabular cement used

Yes 25,313 100% 0 0% 385 5% 284 5% 25,982 47%

No 0 0% 16,416 100% 7,642 95% 5,312 95% 29,370 53%

** Optional field





using cement


Primaryresurfacing

Total


n % n % n % n % n %

Aspirin 6,085 24% 3,752 23% 2,447 30% 1,528 27% 13,812 25%

Chloroquinine 11 0% 5 0% 0 0% 1 0% 17 0%

Low dose heparin 266 1% 508 3% 182 2% 149 3% 1,105 2%

Low molecular weight heparin 16,092 64% 9,831 60% 4,305 54% 2,716 49% 32,944 60%

Pentasaccharide 161 1% 165 1% 58 1% 55 1% 439 1%

Warfarin 458 2% 210 1% 164 2% 140 3% 972 2%

Other chemical 393 2% 258 2% 109 1% 267 5% 1,027 2%

Foot pump 6,595 26% 4,931 30% 2,420 30% 1,480 26% 15,426 28%

Intermittent calf compression 6,315 25% 3,772 23% 1,915 24% 1,230 22% 13,232 24%

TED stockings 14,712 58% 10,265 63% 5,094 63% 3,506 63% 33,577 61%

Other mechanical 225 1% 133 1% 79 1% 35 1% 472 1%

None recorded 98 0% 149 1% 18 0% 21 0% 286 1%




using cement


Primaryresurfacing

Total


n % n % n % n % n %

None specified 25,067 99% 16,167 98% 7,952 99% 5,580 100% 54,766 99%

Total specified 265 259 84 17 625

Calcar crack 46 17% 133 51% 21 25% 1 6% 201 32%

Pelvic penetration 82 31% 16 6% 10 12% 1 6% 109 17%

Shaft fracture 14 5% 17 7% 6 7% 0 0% 37 6%

Shaft penetration 6 2% 5 2% 5 6% 1 6% 17 3%

Trochanteric fracture 57 22% 44 17% 19 23% 0 0% 120 19%

Other 60 23% 44 17% 23 27% 14 82% 141 23%

Table 4.4Thromboprophylaxis regime for primary hip replacement patients prescribed at time of operation, according to procedure

Table 4.5Reported untoward intra-operative events** for primary hip replacement patients in 2006 according to procedure type

NB: More than one event may be recorded for a patient

** Optional field


Table 4.6Patient characteristics for hip revision procedures in 2006, according to procedure type

* Age and gender reported for consenting patients only (75% of revision procedures)



Hip Single StageRevision

Hip Revision (Stage 1 of 2)

Hip Girdlestone Total

Total 4,953 343 59 5,355

Age, years (consenting patients only) n* 3,759 234 34 4,027

Mean (sd) 70 (12) 68 (12) 70 (15) 70 (12)

Interquartile range 64 - 79 61 - 76 62 - 80 63 - 79

n % n % n % n %

Gender (consenting patients only) n* 3,765 n/a 234 n/a 34 n/a 4,033 n/a

Female 2,187 58% 121 52% 19 56% 2,327 58%

Male 1,578 42% 113 48% 15 44% 1,706 42%


P1 – Fit and healthy 742 15% 48 14% 2 3% 792 15%

P2 – Mild disease not incapacitating 2,928 59% 182 53% 31 53% 3,141 59%

P3 – Incapacitating systemic disease 1,207 24% 104 30% 23 39% 1,334 25%

P4 – Life threatening disease 66 1% 8 2% 3 5% 77 1%

P5 – Expected to die within 24hrs 10 0% 1 0% 0 0% 11 0%


Aseptic loosening 3,139 63% 76 22% 13 22% 3,228 60%

Lysis 1,044 21% 52 15% 10 17% 1,106 21%

Pain 982 20% 58 17% 16 27% 1,056 20%

Dislocation/subluxation 717 14% 11 3% 11 19% 739 14%

Periprosthetic fracture 397 8% 13 4% 4 7% 414 8%

Infection 93 2% 278 81% 36 61% 407 8%

Malalignment 325 7% 6 2% 0 0% 331 6%

Fractured acetabulum 94 2% 3 1% 1 2% 98 2%

Fractured stem 75 2% 5 1% 0 0% 80 1%

Fractured femoral head 23 0% 0 0% 0 0% 23 0%

Incorrect sizing/head socket mismatch 43 1% 3 1% 0 0% 46 1%

Wear of acetabular component 663 13% 8 2% 1 2% 672 13%

Dissociation of liner 60 1% 0 0% 0 0% 60 1%

Other 281 6% 9 3% 4 7% 294 5%

Side

Bilateral 0 0% 0 0% 0 0% 0 0%

Left, unilateral 2,484 50% 178 52% 24 41% 2,686 50%

Right, unilateral 2,469 50% 165 48% 35 59% 2,669 50%


Table 4.7Indication for surgery for hip revision procedures in 2004 to 2006

Table 4.8Components removed during hip revision procedures in 2006

Indications for Single Stage Revision – hips 2004 2005 2006

Total 3,016 5,104 4,953

n % n % n %

Aseptic loosening 1,994 66% 3,330 65% 3,139 63%

Lysis 711 24% 1,120 22% 1,044 21%

Pain 518 17% 968 19% 982 20%

Infection 46 2% 84 2% 93 2%

Indications for Two Stage Revision – hips 2004 2005 2006

Total 204 312 343

n % n % n %

Aseptic loosening 90 44% 90 29% 76 22%

Lysis 44 22% 57 18% 52 15%

Pain 33 16% 42 13% 58 17%

Infection 133 65% 229 73% 278 81%


Hip Single StageRevision

Hip Revision (Stage 1 of 2)

Hip Girdlestone Total

Total 4,953 343 59 5,355

n % n % n % n %

Both components (acetabular and femoral) 2,555 52% 292 85% 42 71% 2,889 54%

Acetabular component +/- femoral head 1,252 25% 11 3% 3 5% 1,266 24%

Femoral component alone 845 17% 29 8% 9 15% 883 16%

Femoral head alone 155 3% 0 0% 0 0% 155 3%

None 146 3% 11 3% 5 8% 162 3%


Table 4.9Components used during single stage hip revision procedures in 2006

Table 4.10Types of hip re-operation other than revisions in 2006

2006

Hip Single Stage Revision

Total 4,953

n %

Femoral component cemented

Yes 1,734 35%

No 2,487 50%

Not revised 732 15%

Acetabular component cemented

Yes 1,626 33%

No 2,961 60%

Not revised 366 7%

2006

Total 314

Type of re-operation* n %

Socket augmentation 43 15%

Wound exploration 43 15%

Open reduction of dislocation 25 9%

ORIF** femur 17 6%

Excision of heterotopic bone 7 2%

ORIF** trochanter 5 2%

Focal bone graft only (femur) 4 1%

Focal bone graft only (acetabulum) 1 0%

Other procedure 169 60%

* A procedure can have more than one type of re-operation recorded. There were 314 operations recorded for 283 procedures.

** ORIF = Open Reduction Internal Fixation

** Optional field


Table 4.11Characteristics of patients undergoing hip re-operations other than revision

2006

Total 283

Age, years (consenting patients only) n* 168

Mean (sd) 71(12)

Interquartile range 64 - 79

n %

Gender (consenting patients only) n* 168 n/a

Female 97 58%

Male 71 42%


P1 – Fit and healthy 32 11%

P2 – Mild disease, not incapacitating 160 57%

P3 – Incapacitating systemic disease 88 31%

P4 – Life threatening disease 3 1%

P5 – Expected to die within 24hrs 0 0%

Side

Bilateral 0 0%

Left, unilateral 145 51%

Right, unilateral 138 49%

* Age and gender reported for consenting patients only (59% of re-operation procedures)


Table 4.12Revision at 1 year for primary hip replacement procedures undertaken between 1 April 2003 and 30 September 2006 thatwere linked to a HES episode20

20 Procedures linked to a HES episode were those undertaken in Englandand mainly in NHS hospitals (see Section 2.2 of Part 2)

21 Calculated using the Kaplan-Meier survival analysis method

22 Relative hazard of revision within 1 year of primary hip replacementcompared to a patient with a reference level of the factor (hazard ratio=1),adjusted for all other factors included in the analyses

Factor Category Number ofpatients

Number revised within

1 year

Crude revisionrate21 (95% CI)

Hazard ratio (95% CI)22

Age

< 65 years 26,284 142 1.0% (0.8% - 1.1%) 1.0

65 - 74 years 27,661 138 0.7% (0.6% - 0.8%) 1.0 (0.8 - 1.2)

75 + years 22,630 94 0.6% (0.5% - 0.7%) 1.0 (0.8 - 1.3)

GenderMale 30,868 216 0.9% (0.8% - 1.0%) 1.0

Female 45,680 232 0.6% (0.5% - 0.7%) 0.8 (0.7 - 1.0)

Patientphysicalstatus

P1 – Fit and healthy 18,822 109 0.6% (0.5% - 0.8%) 1.0

P2 – Mild disease not incapacitating 46,144 305 0.7% (0.7% - 0.8%) 1.6 (1.2 - 1.9)

P3+ – Incapacitating systemic disease or worse 11,610 93 0.9% (0.7% - 1.1%) 2.0 (1.5 - 2.7)

Proceduretype

Total replacement using cement 41,232 127 0.3% (0.3% - 0.4%) 1.0

Total replacement not using cement 19,022 168 1.0% (0.8% - 1.1%) 2.9 (2.3 - 3.7)

Hybrid total replacement 10,120 62 0.7% (0.5% - 0.9%) 1.9 (1.4 - 2.5)

Hip resurfacing 6,202 91 1.6% (1.3% - 2.0%) 5.0 (3.7 - 6.7)

Provider type

NHS hospital 68,297 414 0.8% (0.7% - 0.8%) 1.0

Independent hospital 2,951 12 0.4% (0.2% - 0.7%) 0.6 (0.3 - 1.1)

NHS Treatment Centre 4,237 19 0.5% (0.3% - 0.8%) 0.7 (0.4 - 1.0)

Independent Treatment Centre 1,091 3 0.3% (0.1% - 0.9%) 0.5 (0.1 - 1.5)


Primary hip procedure

THR usingcement

THR not usingcement

Hybrid THR HipResurfacing

Total

Total 151 n/a 191 n/a 72 n/a 82 n/a 496 n/a

Cause of failure

Periprosthetic fracture 9 6% 19 10% 10 14% 30 37% 68 14%

Pain 11 7% 19 10% 15 11% 19 23% 60 12%

Aseptic loosening 36 24% 41 21% 14 19% 16 20% 107 22%

Infection 44 29% 25 13% 18 25% 6 7% 93 19%

Malalignment 17 11% 31 16% 6 8% 4 5% 58 12%

Dislocation/subluxation 32 21% 47 25% 16 22% 3 4% 98 20%

Lysis 7 5% 7 4% 6 8% 1 4% 21 4%

Fractured stem 3 2% 6 3% 1 1% 3 4% 13 3%

Fractured acetabulum 1 <1% 0 0% 1 1% 1 1% 98 2%

Fractured femoral head 1 <1% 6 3% 0 0% 1 1% 8 2%

Incorrect sizing/head socket mismatch 1 <1% 3 2% 1 1% 1 1% 6 1%

Wear of acetabular component 0 0% 3 2% 1 1% 0 0% 4 1%

Dissociation of liner 0 0% 3 2% 0 0% 0 0% 3 1%

Other 7 5% 11 6% 2 3% 15 18% 35 7%

Table 4.13Causes of failure for primary hip replacement implants undertaken between 1 April 2003 and 30 September 2006 that werelinked to a HES episode23 and had a revision also linked to a HES episode




Procedure type Number of procedures Deaths Rate25 (95% CI) SMR (95% CI)

Total 45,933 936 1.9% (1.8% - 2.0%) 0.46 (0.43 - 0.49)

Cemented THR 25,804 630 2.3% (2.2% - 2.5%) 0.46 (0.42 - 0.50)

Cementless THR 10,114 178 1.6% (1.4% - 1.8%) 0.49 (0.42 - 0.57)

Hybrid THR 6,590 112 1.6% (1.3% - 1.9%) 0.42 (0.35 - 0.51)

Hip resurfacing 3,425 16 0.4% (0.3% - 0.6%) 0.39 (0.22 - 0.63)

Table 4.14Mortality rates and age-and-gender-standardised mortality ratios at 1 year following primary hip replacement for procedureslinked to a HES episode24, 2003-2005


Table 4.15Mortality at 1 year for primary hip replacement procedures undertaken between 1 April 2003 and 30 June 2006 that werelinked to a HES episode26


27 Relative hazard of death within 1 year of primary hip replacementcompared to a patient with a reference level of the factor (hazard ratio=1),adjusted for all other factors included in the analyses


Number dyingwithin 1 year

Hazard ratio27

(95% CI)

Age

< 65 years 25,980 157 1.0

65 - 74 years 27,551 313 1.5 (1.2 - 1.8)

75+ years 22,784 730 3.7 (3.1 - 4.5)

GenderMale 30,786 558 1.0

Female 45,501 642 0.7 (0.6 - 0.7)


P1 – Fit and healthy 18,873 114 1.0

P2 – Mild disease not incapacitating 45,761 591 1.6 (1.3 - 2.0)

P3+ – Incapacitating systemic disease or worse 11,683 495 4.5 (3.7 - 5.6)

Proceduretype

Total replacement using cement 41,110 809 1.0

Total replacement not using cement 18,725 230 0.9 (0.8 - 1.1)

Hybrid total replacement 10,509 142 0.9 (0.7 - 1.1)

Hip resurfacing 5,973 19 0.5 (0.3 - 0.7)

Provider type

NHS hospital 68,239 1,141 1.0

Independent hospital 2,988 19 0.5 (0.3 - 0.8)

NHS Treatment Centre 4,089 37 0.7 (0.5 - 0.9)

Independent Treatment Centre 1,001 3 0.3 (0.1 - 0.9)


Table 4.16Length of hospital stay following admission for a primary hip replacement for procedures linked to a HES episode28, 2003 – 2006


Average length of stay (days)

(95% CI)

Adjusted difference inaverage LOS* (days)

(95% CI)

Age

<45 years 2,900 7.2 (7.0 – 7.5) 0.0

45 - 54 years 6,513 7.0 (6.9 – 7.2) -0.3 (-0.7 _ 0.1)

55 - 64 years 18,035 7.4 (7.3 – 7.5) -0.2 (-0.5 _ 0.1)

65 - 74 years 28,913 8.5 (8.4 – 8.6) 0.5 (0.2 _ 0.9)

75 - 84 years 20,435 11.2 (11.0 – 11.3) 2.8 (2.4 _ 3.2)

85+ years 3,529 15.1 (14.7 – 15.6) 6.4 (6.0 _ 6.8)

GenderMale 32,379 8.4 (8.3 – 8.5) 0.0

Female 47,918 9.5 (9.4 – 9.6) 0.6 (0.4 _ 0.7)


P1 - Fit and healthy 19,701 7.4 (7.3 – 7.5) 0.0

P2 - Mild disease not incapacitating 48,348 8.9 (8.8 – 8.9) 0.6 (0.5 _ 0.8)

P3 - Incapacitating systemic disease 11,605 12.4 (12.2 – 12.7) 3.5 (3.3 _ 3.7)

P4 - Life threatening disease 672 15.8 (14.4 – 17.2) 6.7 (6.0 _ 7.4)

Proceduretype

Total replacement using cement 43,050 9.7 (9.6 – 9.8) 0.0

Total replacement not using cement 20,132 8.6 (8.4 – 8.7) 0.02 (-0.1_ 0.2)

Hybrid total replacement 10,830 9.1 (8.9 – 9.3) 0.2 (0.03 _ 0.4)

Hip resurfacing 6,314 6.3 (6.2 – 6.4) -1.0 (-1.2 _ -0.7)

Provider type

NHS hospital 71,713 9.4 (9.3 – 9.5) 0.0

Independent hospital 3,050 6.3 (6.1 – 6.5) -2.5 (-2.9 _ -2.2)

NHS Treatment Centre 4,420 6.7 (6.6 – 6.9) -3.5 (-4.0 _ -3.0)

Independent Treatment Centre 1,143 5.4 (5.1 – 5.6) -2.6 (-2.8 _ -2.3)

* Difference in average length of stay compared to reference level (average difference=0 days) after adjusting for other factors

28 Procedures linked to a HES episode were those undertaken in Englandand mainly in NHS hospital (see Section 2.2 of Part 2)


Table 4.17Length of hospital stay following admission for a primary hip procedure according to age and gender for procedures linked toa HES episode29, 2003 – 2006


Patient characteristics

Female < 55 years Female > 55 years Male < 55 years Male > 55 years Total

Total 4,678 7.5 5 - 8 43,240 9.7 6 - 10 4,734 6.7 5 - 7 27,645 8.8 5 - 9 80,297 9.1 6 - 10

Procedure type

n Mea

n (d

ays)

Inte

rqua

rtile

ran

ge(d

ays)

n Mea

n (d

ays)

Inte

rqua

rtile

ran

ge(d

ays)

n Mea

n (d

ays)

Inte

rqua

rtile

ran

ge(d

ays)

n Mea

n (d

ays)

Inte

rqua

rtile

ran

ge(d

ays)

n Mea

n (d

ays)

Inte

rqua

rtile

ran

ge(d

ays)

THR usingcement

961 8.5 6 - 9 26,693 10.1 6 - 11 787 7.5 5 - 8 14,592 9.2 6 -10 43,033 9.8 6 - 10

THR not usingcement

1,620 7.7 5 - 8 9,862 9.1 6 - 9 1,489 7.0 5 - 7 7,151 8.3 5 - 9 20,122 8.6 5 - 9

Hybrid orreverse hybridTHR

779 7.9 5 - 8 5,596 9.5 6 - 10 615 7.0 5 - 8 3,838 9.0 6 - 9 10,828 9.1 6 - 9

Hip resurfacing

1,318 6.3 5 - 7 1,089 6.9 5 - 8 1,843 5.9 4 - 7 2,064 6.3 5 - 7 6,314 6.3 5 - 7

Part 25. Knee Replacement Procedures



5.1 Knee Replacement Procedures, 2006

This section summarises the patient characteristics of all57,597 primary, 3,048 revision and 341 re-operation kneereplacement procedures undertaken between 1 January2006 and 31 December 2006 and entered into the NJR by28 February 2007. Fields for which data entry is optional areindicated in the tables of results. All optional fields, apartfrom “untoward intra-operative events”, were reported inmore than 80% of procedures.

5.1.1 Primary knee replacement procedures, 2006

Over 80% of the 57,597 primary knee replacement proceduresundertaken in 2006 were cemented total knee replacement(TKR) procedures and 4,533 (8%) were unicondylar kneereplacements (Table 5.1). Compared with previous years thetypes of primary knee replacement procedures undertakenhave largely remained the same.


The average age was 70 years and 57% of the patients werefemale. Patients undergoing a patello-femoral replacementwere the youngest, at an average age of 61 years, withthree-quarters of these being female. On average, femalepatients were one year older than male patients at the timeof their primary knee replacement (70 years and 69 years,respectively, Table 5.2). According to the American Societyof Anaesthesiologists (ASA) grade system,18% of thepatients undergoing a primary knee replacement procedurewere graded as “fit and healthy” (Table 5.1). The singlelargest indication recorded for surgery was osteoarthritis,recorded in 97% of all primary procedures.

Compared with previous years, the patient characteristicsdescribed above have largely remained unchanged. However,there has been an increase in patients with mild or incapacitatingdisease prior to surgery. For example, patients with mild diseaseincreased from 62% in 2004 to 68% in 2006. A similar trendin the recorded ASA grade of patients was seen in primaryhip replacement procedures.

5.1.1.2 Surgical techniques

The most common surgical approach was the medialparapatellar, used in over 90% of procedures (Table 5.3).Where recorded minimally invasive surgery (MIS) was usedin over half of unicondylar knee replacement procedures,compared with use in 3% of all other types of kneereplacement procedures.

Compared with previous years, the surgical techniques used in primary knee replacements have largely remainedunchanged. There was, however, an increase in the use ofMIS in unicondylar knee replacements from 37% in 2004 to56% in 2006.


The most frequently prescribed chemical method was lowmolecular weight heparin, and TED stockings were the mostfrequently prescribed mechanical method (Table 5.4).

Compared with previous years, there has been an increasein the prescription of a combined chemical and mechanicalregime from 49% in 2004 to 60% in 2006. The increase canbe attributed to similar changes in the prescription of lowmolecular weight heparin, which increased from 49% in 2004 to 57% in 2006, and TED stockings which increasedfrom 55% in 2004 to 62% in 2006. A marginal increase was also seen in the prescription of a foot pump from 24% in 2004 to 28% in 2006. A similar trend in the prescribedthromboprophylaxis regime was found in primary hipreplacement procedures.

5.1.1.4 Untoward intra-operative events

Table 5.5 shows that untoward intra-operative events wererare, reported in 0.5% of procedures. Completion of the datafield requesting these events was not mandatory and thedefault option, which held when the field was not completed,was that no untoward intra-operative event occurred. Of the265 untoward events reported, over a third were fractures.Compared with previous years, the frequency and pattern of untoward intra-operative events has largely remained the same.

5.1.2 Knee revisions, 2006

A total of 3,048 knee revision procedures were reported.This includes 431 (14%) procedures that were Stage 2 of atwo-stage revision procedure that have been excluded fromthe rest of the section. Of the remaining 2,617 procedures,2,242 (86%) were single stage revision operations and 359(14%) were Stage 1 of a two-stage process (Table 5.6). A further 16 (<1%) procedures were recorded, comprising13 conversions of previous knee replacements to arthrodesisand 3 knee amputations. Compared with previous years,there has been no change in the types of revision procedurescarried out.


The mean age of knee revision patients was 70 years (Table 5.6). There were more female (52%) than malepatients (48%). Aseptic loosening was the most commonindication for single stage revision and infection was themost common indication for two-stage revision.

Compared with previous years, the patient characteristicsdescribed above have largely remained the same. However,there was an increase in patients with mild or incapacitatingdisease. For example, procedures in patients with milddisease increased from 59% in 2004 to 64% in 2006.

5.1.2.2 Components removed

In three-quarters of the revision procedures, the femoral andtibial components were both removed (Table 5.7).


5.1.3 Knee re-operations other thanrevision, 2006

A total of 341 knee re-operation procedures undertaken afteran initial knee replacement were recorded. Of all re-operations,178 (52%) involved resurfacing of the patella and 44 (13%)were reported as manipulation under anaesthesia (Table 5.8).29% of the re-operations had other descriptions outside of thelist of options given and included exchange of the tibial insert.

The characteristics of patients undergoing a knee re-operationin 2006 are shown in Table 5.9. The average age of thepatients was 69 years and half of these were female.

5.2 Outcomes Following Primary KneeReplacement, 2003 – 2006

This section presents analyses of revision, mortality ratesand length of stay for primary knee replacement procedures.Particular emphasis is also given to revision of unicondylarknee replacements. The analyses are based on proceduresundertaken between 1 April 2003 and 30 September 2006 thatwere linked to an episode in the HES database. As explainedin Section 2.2, the linked procedures were those undertakenin England, and mainly in NHS hospitals. A description ofthe linkage process, as well as the patient characteristics ofthe linked procedures is also included in Section 2.2.

5.2.1 Revision

All 80,696 primary knee replacement procedures in the NJR thatwere undertaken between 1 April 2003 and 30 September 2006and linked to a HES episode that was also defined as aprimary knee replacement procedure were identified. Of thelinked primary knee replacement procedures, 75,944 (94%)were undertaken at NHS hospitals and NHS treatment centresand 4,752 (6%) were undertaken in the independent sector.

In HES, primary knee replacements for the patients withlinked procedures were identified using the following OPCS-4 procedure codes:

W401 – Primary total prosthetic replacement of knee jointusing cement.

W411 – Primary total prosthetic replacement of knee jointnot using cement.

W421 – Primary total prosthetic replacement of knee jointnot elsewhere classified (nec).

W581 – Primary resurfacing arthroplasty of joint (used only ifprocedure code Z846 (knee joint) is also specified).

W521 – Primary prosthetic replacement of articulation ofbone using cement nec.

Procedure type (n)

Cemented (68,904)

Cementless (5,904)

Unicondylar (4,110)

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

1 year

0.3% (0.3% - 0.4%)

0.3% (0.2% - 0.6%)

0.5% (0.3% - 0.8%)

1 year

1.3% (1.2% - 1.5%)

1.5% (1.0% - 2.0%)

2.4% (1.4% - 4.1%)

0 1 2 3



Cemented TKR

Unicondylar

Cementless TKR

Figure 5.1Revision rate estimates forHES-linked primary kneereplacement procedures, 2003 – 2006


Some patients had two primary knee replacement procedures,one on each side, which occurred on different dates andwere both linked to a HES record. In such cases, to avoidincluding a patient twice in the linked database, only theearliest primary procedure was retained. For each linkedpatient, all hospital episodes recorded in HES that succeededthe primary procedure were identified. From these succeedingepisodes, the first knee revision that occurred on the sameside as the primary procedure was then identified in HES.Where the side of the primary or the revision was not given, thefirst revision that occurred after the primary procedure wasassumed to be a revision of that primary. In HES, revisionprocedures were identified using the procedure codesW403, W413, W423, W582 (only with Z846) and W523indicating revision of a cemented, cementless, unclassified,knee resurfacing, and replacement of articulation of boneprimary procedure, respectively. In addition, revision codesindicating conversion from one type of replacement to another,as well as attention to the replacement joint in which therewas renewal of the prosthesis, were also identified as revisions.Codes indicating other types of attention to the hip replacementjoint, such as correction of displacement of prosthesis, wereconsidered to be re-operations and were not included as revisions.

Using the revisions identified in HES as described above,revision rates were then estimated for various patientcharacteristics, as well as procedure and provider types. The number of linked hybrid total knee replacements andpatello-femoral replacements was too low to allow reliableestimates of revision rates to be obtained and these proceduresare therefore excluded from the results presented below.Revision rates were estimated using the Kaplan-Meier survivalanalysis method that allows prostheses that are followed upfor unequal lengths of time after implant to be included.

5.2.1.1 Procedure type

The overall revision rate for primary knee replacement was 0.4%(95% CI 0.3% to 0.4%) at 1 year and 1.4% (95%CI: 1.2% to1.6%) at 3 years. Figure 5.1 shows estimates of implant survivalto revision by procedure type, together with revision rateswithin 1 year and 3 years following primary knee replacement.

5.2.1.2 Age and gender

Figure 5.2 shows revision rates by procedure type for patientsaged less than 65 years and those aged 65 and over, separately.Revision rates in older patients were lower than those inyounger patients.

0 1 2 3

0.5% (0.4% - 0.6%)

0.5% (0.2% - 1.1%)

0.8% (0.4% - 1.4%)

Cemented TKR

Cementless TKR

Unicondylar

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

Cemented TKR

Cementless TKR

UnicondylarAnalysis time (years from operation)

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –0 1 2 3


Age <65 years Age 65+ years


0.3% (0.3% - 0.4%)

0.3% (0.2% - 0.6%)

0.4% (0.2% - 0.8%)

Cemented TKR

Cementless TKR

Unicondylar


Kap

lan-

Mei

er s

urvi

val e

stim

ate

Figure 5.2Revision rate estimates by agefor HES-linked primary kneereplacement procedures, 2003 – 2006


Figure 5.3Survival to revision andrevision rates for male and female patients with HES-linked primary kneereplacement procedures,2003-2006

0 1 2 3

0.3% (0.3% - 0.4%)

0.2% (0.1% - 0.5%)

0.3% (0.1% - 0.7%)

Cemented TKR

Cementless TKR

Unicondylar

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

Cemented TKR

Cementless TKR

Unicondylarreplacement


1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –0 1 2 3


Female Male


0.4% (0.3% - 0.5%)

0.6% (0.3% - 1.0%)

0.8% (0.4% - 1.3%)

Cemented TKR

Cementless TKR

Unicondylar


Kap

lan-

Mei

er s

urvi

val e

stim

ate

Figure 5.3 shows revision rates for female and male patientsseparately. Revision rates were lower in female patients thanin male patients, but the differences were not statisticallysignificant.


Table 5.10 shows the results of a multivariable analysis inwhich the impact of patient age, gender and physical status,as well as procedure and provider type on 1-year revisionrates is explored (see Section 4.2.1 for an explanation ofmultivariable analyses and hazard ratios). There was nosignificant difference in revision rates across the differentprocedure types after adjusting for age, gender, physicalstatus and provider type.

5.2.1.3 Comparison of revision rates with other registries

A comparison of revision rates in the NJR with thosereported in other national registries showed that the ratesreported in the NJR were generally lower than thosereported elsewhere30,31,32. However, there were differences inthe definition of what a revision is across registries, withsome registries including re-operations with revisions.Furthermore, revisions were specified for different timeperiods and it has been shown that revision rates haveimproved significantly over time.

5.2.1.4 Revision rates for most frequently used implant brands

Figure 5.4 shows revision rates for the five most commonlyused brands of total condylar knee replacement prostheses.

There were no statistically significant differences in 1 and 3-year revision rates among the different brands.

30 Australian Orthopaedic Association National Joint Replacement RegistryAnnual Report 2006. https://www.dmac.adelaide.edu.au/aoanjrr/documents/aoanjrrreport_2006.pdf

31 The Norwegian Arthroplasty Register, 2006. http://www.haukeland.no/nrl/

32 Swedish Knee Arthroplasty Register Annual Report 2006.http://www.knee.nko.se/english/online/thePages/publication.php

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –0 1 2 3


AGC

Kinemax

Nexgen

PFC Sigma

Scorpio

Brand (n)

AGC (10,203)

Kinemax (5,091)

Nexgen (9,857)

PFC Sigma (26,833)

Scorpio (5,386)

1 year

0.3% (0.2% - 0.5%)

0.3% (0.3% - 0.7%)

0.2% (0.1% - 0.3%)

0.4% (0.3% - 0.5%)

0.3% (0.2% - 0.5%)

3 years

1.2% (0.9% - 1.6%)

1.6% (1.2% - 2.2%)

0.8% (0.5% - 1.2%)

1.3% (1.1% - 1.6%)

1.6% (1.0% - 2.5%)


Figure 5.4Revision rate estimates for the five most commonly usedbrands of total condylar kneeprostheses, 2003 – 2006


5.2.2 Unicondylar knee replacement procedures

This section presents results of detailed analyses ofunicondylar knee procedures, focusing on revision rates forthe most commonly used brand of prostheses, causes offailure compared to other types of primary knee replacementas well as revision rates of procedures where minimallyinvasive surgery was used.

Figure 5.5 shows revision rates for the Oxford III unicondylarknee prostheses, which is the most frequently used brand.There were insufficient procedures performed to allowreliable estimates of revision rates to be obtained for otherbrands of unicondylar knee prostheses.

5.2.2.1 Causes of failure

Table 5.11 shows causes of failure for different primary kneereplacement procedure types. The most common causes offailure for unicondylar knee procedures were aseptic looseningand pain. In comparison, the most common cause of failurefor cemented TKR procedures was infection.

5.2.2.2 Use of minimally invasive surgery

Recent trends show an increase in the use of minimallyinvasive surgery (MIS) in unicondylar knee replacement(Section 5.1.1.2). Figure 5.6 shows revision rates forunicondylar knee replacement procedures in which MIS wasused and those in which conventional methods were used.

There were no statistically significant differences in 1 yearrevision rates following unicondylar knee replacementbetween procedures in which MIS was used and proceduresin which conventional methods were used.

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –0 1 2 3


Brand (n)

Oxford III (2,664)

1 year

0.6% (0.3% - 1.1%)

3 years

2.6% (1.3% - 5.3%)


Figure 5.5Revision rate estimates for the five most commonly usedbrands of total condylar kneeprostheses, 2003 – 2006


5.2.3 Mortality

This section summarises mortality rates for primary kneereplacement patients for procedures undertaken between 1April 2003 and 30 June 2006 that were linked to a HESrecord. At the time of analyses, dates of death were onlyavailable up to 30 June 2006 and only those proceduresundertaken up to this date could therefore be analysed.

The mortality rate of primary knee replacement patients was1.6% (95% CI 1.5% - 1.7%) at 1 year and 5.1% (95% CI 4.7%- 5.5%) at 3 years. Mortality rates at 1 year following primaryknee replacement were compared with those of the generalpopulation of England and Wales using age and sex adjustedstandardised mortality ratios (Table 5.12). The comparisonshowed that mortality among knee replacement patients is about a third of that observed in the general age and sex-matched population, with the overall SMR being 0.35(95% CI 0.33-0.38).

Table 5.13 shows mortality rates at 1 year following a primaryknee replacement by patient age, sex and physical status aswell as procedure and provider type, together with results ofa multivariable analysis (see Section 4.2.1 for an explanationof multivariable analyses and hazard ratios). After adjustingfor confounding factors, mortality within 1 year remainshigher for older patients and those in a poor general medicalcondition, but lower for female than male patients. Mortalityat 1 year following unicondylar knee replacement is lowerthan that following cemented total knee replacement afteradjusting for age, sex and patient physical status. However,interpretation of the results is complicated by the differencesin patient characteristics across the procedure types.


Mortality rates up to 1 year following primary kneereplacement were compared between patients with differenttypes of thromboprophylaxis prescribed at the time ofsurgery, including those for whom none was prescribed.There were no statistically significant differences in mortalitybetween the different types prescribed (Figure 5.7).

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –0 3 6 9 12


MIS used (1,581)

MIS not used (2,142)

1 year

0.2% (0.1% - 0.9%)

0.8% (0.4% - 1.6%)

Revision rate (95% Cl)Minimally invasivesurgery used

Minimally invasivesurgery not used

MIS use (n)

Figure 5.6Revision rates comparing use and non-use of minimallyinvasive surgery inunicondylar knee procedures, 2003 – 2006


5.2.4 Length of stay

This section presents results for the analysis of length ofhospital stay following admission for primary knee replacementprocedures linked to a HES episode. Table 5.14 gives theaverage length of stay for several patient characteristics, aswell as procedure and provider type. The average length ofstay was calculated as the total number of bed days dividedby the number of patients.

The average length of stay following primary knee replacementwas 8.1 days. The length of stay is influenced by severalfactors, including those shown in Table 5.14. Patients whoundergo unicondylar knee replacement procedures are onaverage younger than those who undergo total kneereplacement, and this difference in average age should betaken into account in comparing the length of stay acrossdifferent procedure types. The difference in average lengthof stay shown for each factor in Table 5.14 is adjusted for theother factors in the table. Patients stayed on average, 5.9days following a primary unicondylar knee replacementcompared with an average of 8.3 days following a cemented

TKR procedure – a difference of about 2 days. The differencein the average length of stay between the two proceduretypes remained the same after adjusting for the other factors(shown in Table 5.14).

3 months

0.5% (0.3% - 1.1%)

0.6% (0.5% - 0.7%)

0.5% (0.4% - 0.6%)

0.5% (0.5% - 0.6%)

None prescribed[n=1,376]

Chemical only [n=19,033]

Mechanical only [n=14,150]

Both types[n=43,399]

1.00 –

0.98 –

0.96 –

0.94 –

0.92 –

0.90 –

6 months

0.9% (0.5% - 1.6%)

0.9% (0.8% - 1.1%)

0.8% (0.6% - 0.9%)

0.9% (0.8% - 1.0%)

1 year

2.0% (1.4% - 2.9%)

1.6% (1.4% - 1.8%)

1.5% (1.3% - 1.8%)

1.6% (1.5% - 1.8%)

0 3 6 129


Mortality rate (95% Cl)

None prescribed

Chemical only

Mechanical only

Both types

Figure 5.7Mortality for patients with and those without anythromboprophylaxisprescribed at the time ofprimary knee replacement,2003 – 2006




Totalreplacement

not usingcement

Hybrid Unicondylarknee

replacement

Patello-femoralreplacement

Total

Total 47,626 4,088 702 4,533 648 57,597

Age, years (consentingpatients only) n*

38,908 n/a 3,194 n/a 591 n/a 3,754 n/a 495 n/a 46,942 n/a

Mean (sd) 71 (9) n/a 69 (10) n/a 69 (10) n/a 65 (10) n/a 61 (12) n/a 70 (10) n/a

Interquartile range 64 - 77 n/a 62 - 76 n/a 62 - 77 n/a 58 - 72 n/a 52 - 70 n/a 63 - 77 n/a

n % n % n % n % n % n %

Gender (consentingpatients only) n*

38,995 n/a 3,202 n/a 591 n/a 3,766 n/a 495 n/a 47,049 n/a

Male 16,422 42% 1,511 47% 266 45% 1,894 50% 122 25% 20,215 43%

Female 22,573 58% 1,691 53% 325 55% 1,872 50% 373 75% 26,834 57%


P1 – Fit and healthy 7,646 16% 817 20% 149 21% 1,263 28% 211 33% 10,086 18%

P2 – Mild disease notincapacitating

32,671 69% 2,663 65% 465 66% 2,918 64% 391 60% 39,108 68%

P3 – Incapacitatingsystemic disease

7,057 15% 589 14% 86 12% 341 8% 44 7% 8,117 14%

P4 – Life threateningdisease

218 0% 17 0% 2 0% 10 0% 2 0% 249 0%

P5 – Expected to diewithin 24hrs

34 0% 2 0% 0 0% 1 0% 0 0% 37 0%


Osteoarthritis 46,074 97% 3,978 97% 673 96% 4,496 99% 629 97% 55,850 97%

Avascular necrosis 207 0% 6 0% 6 1% 39 1% 1 0% 259 0%

Other inflammatoryarthopathy

278 1% 18 0% 7 1% 2 0% 1 0% 306 1%

Infection 34 0% 4 0% 2 0% 2 0% 0 0% 42 0%

Rheumatoid arthritis 1,098 2% 85 2% 11 2% 3 0% 3 0% 1,200 2%

Trauma 271 1% 28 1% 10 1% 8 0% 5 1% 322 1%

Other 440 1% 48 1% 12 2% 20 0% 20 3% 540 1%

Side

Bilateral 359 1% 66 2% 14 2% 135 3% 36 6% 610 1%

Left, unilateral 22,399 47% 1,899 46% 307 44% 2,207 49% 282 44% 27,094 47%

Right, unilateral 24,868 52% 2,123 52% 381 54% 2,191 48% 330 51% 29,893 52%

5 Knee Replacement Procedures

Table 5.1Patient characteristics for primary knee replacement procedures in 2006, according to type of procedure




Table 5.2Age and gender for primary knee replacements in 2006





using cement

Hybrid totalreplacement

Unicondylarknee

replacement


Overall

Average age by gender*

Female n 22,526 n/a 1,686 n/a 325 n/a 1,870 n/a 373 n/a 26,780 n/a

Mean (sd), Interquartile range

71 (9) 65 - 78 69 (10) 62 - 77 69 (10) 62 - 78 65 (10) 57 - 72 60 (11) 52 - 68 70 (10) 64 - 77

Male n 16,377 n/a 1,508 n/a 266 n/a 1,883 n/a 122 n/a 20,156 n/a

Mean(sd), Interquartile range

70 (9) 64 - 77 69 (9) 62 - 76 68 (11) 61 - 76 65 (9) 59 - 71 61 (13) 50 - 72 69 (9) 63 - 76

Age group by gender* n % n % n % n % n % n %

Female

< 45 years 136 1% 24 1% 1 0% 29 2% 28 8% 218 1%

45 - 54 years 975 4% 108 6% 23 7% 291 16% 98 26% 1,495 6%

55 - 64 years 4,672 21% 429 25% 96 30% 678 36% 122 33% 5,997 22%

65 - 74 years 8,470 38% 596 35% 100 31% 555 30% 86 23% 9,807 37%

75 - 84 years 7,166 32% 467 28% 88 27% 287 15% 31 8% 8,039 30%

> 85 years 1,107 5% 62 4% 17 5% 30 2% 8 2% 1,224 5%

Male

< 45 years 125 1% 8 1% 9 3% 30 2% 14 11% 186 1%

45 - 54 years 704 4% 86 6% 25 9% 221 12% 26 21% 1,062 5%

55 - 64 years 3,951 24% 433 29% 67 25% 728 39% 27 22% 5,206 26%

65 - 74 years 6,461 39% 571 38% 92 35% 624 33% 33 27% 7,781 39%

75 - 84 years 4,572 28% 370 25% 65 24% 254 13% 18 15% 5,279 26%

> 85 years 564 3% 40 3% 8 3% 26 1% 4 3% 642 3%


Table 5.3Characteristics of surgical practice for primary knee replacement procedures in 2006, according to type of procedure


Totalreplacement using cement


using cement


replacement


Total

Total 47,626 4,088 702 4,533 648 57,597

n % n % n % n % n % n %

Laminar flow theatre**

Yes 40,382 98% 3,241 97% 583 93% 3,853 97% 543 97% 48,602 98%

No 854 2% 108 3% 45 7% 104 3% 16 3% 1,127 2%

Not recorded 6,390 n/a 739 n/a 74 n/a 576 n/a 89 n/a 7,868 n/a

Surgical approach

Lateral parapatellar 646 1% 67 2% 9 1% 141 3% 42 6% 905 2%

Medial parapatellar 44,032 92% 3,775 92% 601 86% 4,131 91% 542 84% 53,081 92%

Sub-vastus 736 2% 83 2% 80 11% 48 1% 11 2% 958 2%

Other 2,212 5% 163 4% 12 2% 213 5% 53 8% 2,653 5%

Minimally invasive surgery**

Yes 1,178 3% 116 3% 8 1% 2,216 56% 48 9% 3,566 7%

No 41,412 97% 3,384 97% 638 99% 1,745 44% 479 91% 47,658 93%


Image guided surgery**

Yes 771 2% 166 5% 7 1% 103 3% 8 2% 1,055 2%

No 41,724 98% 3,335 95% 644 99% 3,834 97% 516 98% 50,053 98%


Femoral bonegraft used**

Yes 136 0% 27 1% 6 1% 1 0% 0 0% 170 0%

No 47,490 100% 4,061 99% 696 99% 4,532 100% 648 100% 57,427 100%

Tibial bonegraft used**

Yes 139 0% 33 1% 5 1% 3 0% 0 0% 180 0%

No 47,487 100% 4,055 99% 697 99% 4,530 100% 648 100% 57,417 100%

Femoral cement used

Yes 47,625 100% 8 0% 144 21% 4,427 98% 583 90% 52,787 92%

No 1 0% 4,080 100% 558 79% 106 2% 65 10% 4,810 8%

Tibial cement used

Yes 47,624 100% 9 0% 572 81% 4,424 98% 0 0% 52,629 91%

No 2 0% 4,079 100% 130 19% 109 2% 648 100% 4,968 9%

Patella cement used

Yes 20,157 46% 180 5% 448 51% 299 10% 522 87% 21,606 42%

No 23,216 54% 3,183 95% 434 49% 2,607 90% 76 13% 29,516 58%


** Optional field


Table 5.4Thromboprophylaxis regime for primary knee replacement patients prescribed at time of operation, according to procedure

Table 5.5Reported untoward intra-operative events** for primary knee replacement patients in 2006 according to procedure type




using cement


replacement


Total

Total 47,626 4,088 702 4,533 648 57,597

n % n % n % n % n % n %

Aspirin 12,419 26% 1,013 25% 127 18% 1,173 26% 154 24% 14,886 26%

Chloroquinine 25 0% 4 0% 0 0% 2 0% 0 0% 31 0%

Low dose heparin 906 2% 93 2% 6 1% 46 1% 6 1% 1,057 2%

Low molecular weightheparin

27,739 58% 2,240 55% 324 46% 2,306 51% 315 49% 32,924 57%

Pentasaccharide 281 1% 2 0% 1 0% 42 1% 4 1% 330 1%

Warfarin 578 1% 44 1% 9 1% 33 1% 8 1% 672 1%

Other chemical 495 1% 21 1% 6 1% 28 1% 9 1% 559 1%

Foot pump 13,118 28% 1,594 39% 293 42% 1,083 24% 231 36% 16,319 28%

Intermittent calfcompression

11,149 23% 1,285 31% 192 27% 1,272 28% 133 21% 14,031 24%

TED stockings 29,044 61% 2,881 70% 515 73% 2,800 62% 409 63% 35,649 62%

Other mechanical 473 1% 18 0% 6 1% 28 1% 13 2% 538 1%

None 586 1% 21 1% 2 0% 34 1% 9 1% 652 1%

NB: More than one event may be recorded for a patient

** Optional field




using cement


replacement


Total

Total 47,626 4,088 702 4,533 648 57,597

n % n % n % n % n % n %

None specified 47,432 99.6% 4,076 99.7% 696 99.1% 4,520 99.7% 645 99.5% 57,369 99.6%

Total specified 227 n/a 14 n/a 6 n/a 15 n/a 3 n/a 265 n/a

Fracture 78 34.4% 7 50.0% 4 66.7% 9 60.0% 0 0.0% 98 37.0%

Patella tendon avulsion 19 8.4% 1 7.1% 1 16.7% 0 0.0% 0 0.0% 21 7.9%

Ligament injury 31 13.7% 0 0.0% 0 0.0% 1 6.7% 0 0.0% 32 12.1%

Other 99 43.6% 6 42.9% 1 16.7% 5 33.3% 3 100.0% 114 43.0%


Table 5.6Patient characteristics for knee revision procedures in 2006, according to procedure type


Knee Single StageRevision

Knee Revision(Stage 1 of 2)

Knee conversion toarthrodesis

Knee amputation Total

Total 2,242 359 13 3 2,617

Age, years (consenting patients only) n*

1,735 258 8 1 2,002

Mean (sd) 70 (10) 70 (10) 78 (6) 86 70 (10)

Interquartile range 63 - 78 64 - 77 73 - 80 n/a 63 - 77

n % n % n % n % n %

Gender (consenting patients only) n*

1,742 n/a 259 n/a 8 n/a 1 n/a 2,010 n/a

Male 812 47% 147 57% 4 50% 0 n/a 963 48%

Female 930 53% 112 43% 4 50% 1 n/a 1,047 52%


P1 – Fit and healthy 289 13% 41 11% 1 8% 0 0% 331 13%

P2 – Mild disease, not incapacitating

1,446 64% 217 60% 5 38% 0 0% 1,668 64%

P3 – Incapacitating systemicdisease

482 21% 98 27% 6 46% 3 100% 589 23%


P5 – Not expected to survive 24 hours

0 0% 0 0% 0 0% 0 0% 0 0%


Aseptic loosening 1,020 45% 43 12% 2 15% 0 0% 1,065 41%

Pain 468 21% 27 8% 1 8% 0 0% 496 19%

Lysis 271 12% 56 16% 1 8% 0 0% 328 13%

Wear of polyethylenecomponent

341 15% 13 4% 0 0% 0 0% 354 14%

Instability 365 16% 20 6% 2 15% 0 0% 387 15%

Infection 74 3% 301 84% 8 62% 1 33% 384 15%

Malalignment 214 10% 9 3% 0 0% 0 0% 223 9%

Dislocation/subluxation 151 7% 5 1% 0 0% 0 0% 156 6%

Periprosthetic fracture 91 4% 6 2% 0 0% 0 0% 97 4%

Stiffness 123 5% 12 3% 3 23% 1 33% 139 5%

Implant fracture 43 2% 2 1% 0 0% 0 0% 45 2%

Component dissociation 56 2% 4 1% 0 0% 0 0% 60 2%

Other 191 9% 13 4% 2 15% 1 33% 207 8%

Side

Bilateral 2 <1% 0 0% 0 0% 0 0% 2 <1%

Left, unilateral 1,076 48% 180 50% 6 4% 1 33% 1,263 48%

Right, unilateral 1,164 51% 179 50% 7 54% 2 67% 1,352 52%

* Age and gender reported for consenting patients only(77% of revision procedures)



Table 5.7Combinations of implants removed during Single and 2-Stage Knee Revision procedures in 2006

Table 5.8Types of knee re-operations entered into the NJR database


Knee Single Stage Revision

Knee Revision (Stage 1 of 2)

Total

Total 2,242 359 2,601

n % n % n %

Femoral component and not tibial component 185 8% 6 2% 191 7%

Tibial component and not femoral component 146 7% 3 1% 149 6%

Femoral component + tibial component 1,656 74% 330 92% 1,986 76%

Other combination (not femoral or tibial component) 255 11% 20 6% 275 11%

2006

Total 380

Type of re-operation* n %

Resurfacing of patella 178 52%

Manipulation under anaesthesia 44 13%

Washout 18 5%

Wound debridement 21 6%

Soft tissue repair/realignment 12 4%

ORIF** peri-prosthetic fracture 7 2%

Other procedure 100 29%

* A procedure can have more than one type of re-operation recorded.There were 380 re-operations recorded for 341 procedures

** ORIF = Open Reduction Internal Fixation


Table 5.9Characteristics of patients undergoing knee re-operations other than revision


Mean (sd)

Interquartile range


Male

Female


P1 – Fit and healthy

P2 – Mild disease, not incapacitating


P4 – Life threatening disease

P5 – Not expected to survive 24 hours

Side

Bilateral

Left, unilateral

Right, unilateral

234

69 (11)

62 - 76

n

234

117

117

49

214

74

3

1

3

149

189

%

50%

50%

14%

63%

22%

1%

<1%

1%

44%

55%

2006

Total 341

* Age and gender reported for consenting patients only (69% of re-operation procedures)


Table 5.10Revision at 1 year for primary knee replacement procedures undertaken between 1 April 2003 and 30 September 2006 that were linked to a HES episode33

Age

Gender


Procedure type

Provider

type

< 65 years

65 - 74 years

75+ years

Male

Female


P2 – Mild disease not incapacitating

P3+ – Incapacitating systemic disease or worse

Total replacement using cement

Total replacement not using cement

Unicondylar replacement

NHS hospital

Independent hospital



Factor Category Number of

patients

Number revised

within 1 yearCrude revision rate34

(95% CI)

Hazard ratio35

(95% CI)



35 Relative hazard of revision within 1 year of primary knee replacementcompared to a patient with a reference level of the factor (hazard ratio=1),adjusted for all other factors included in the analyses

0.5% (0.4% - 0.6%)

0.4% (0.3% - 0.4%)

0.3% (0.2% - 0.4%)

0.4% (0.4% - 0.5%)

0.3% (0.3% - 0.4%)

0.4% (0.3% - 0.5%)

0.3% (0.3% - 0.4%)

0.4% (0.3% - 0.6%)

0.3% (0.3% - 0.4%)

0.4% (0.2% - 0.6%)

0.5% (0.3% - 0.8%)

0.4% (0.3% - 0.4%)

0.4% (0.2% - 0.7%)

0.2% (0.1% - 0.5%)

0.0% (–)

20,581

30,892

27,443

33,415

45,476

14,965

51,141

12,812

68,904

5,904

4,110

69,400

3,478

4,961

1,079

73

87

64

116

108

51

127

46

188

19

17

204

11

9

0

1.0

0.8 (0.6 - 1.1)

0.7 (0.5 - 0.9)

1.0

0.7 (0.5 - 0.9)

1.0

0.8 (0.6 - 1.2)

1.2 (0.8 - 1.9)

1.0

1.1 (0.7 - 1.8)

1.3 (0.8 - 2.2)

1.0

1.0 (0.5 - 1.8)

0.7 (0.4 - 1.4)

-


Table 5.11Causes of failure for primary knee replacement implants undertaken between 1 April 2003 and 30 September 2006 that werelinked to a HES episode36 and had a revision also linked to a HES episode

Total

Cause of failure

Aseptic loosening

Pain

Instability

Infection

Dislocation/subluxation

Malalignment

Periprosthetic fracture

Wear of polyethylene component

Lysis

Stiffness

Implant fracture

Component dissociation

Other

342

60

43

34

120

11

19

10

6

14

23

1

2

15

18%

13%

10%

35%

3%

5%

3%

2%

4%

7%

<1%

<1%

4%

37

9

9

7

6

3

6

1

0

1

1

0

1

2

24%

24%

19%

16%

8%

16%

3%

0%

3%

3%

0%

3%

5%

69

22

22

6

5

4

3

3

2

1

2

1

1

11

32%

32%

9%

7%

6%

4%

4%

3%

1%

1%

1%

1%

16%

448

91

74

47

131

18

28

14

8

16

26

2

4

28

20%

17%

10%

29%

4%

6%

3%

2%

4%

6%

<1%

1%

6%

Primary knee procedure

TKR using cement TKR not using cement Unicondylar knee replacement Total

36 Procedures linked to a HES episode were those undertaken in Englandand mainly in NHS hospitals (see Section 2.2)

Table 5.12Mortality rates and age-and-gender-standardised mortality ratios at 1 year following primary knee replacement for procedureslinked to a HES episode37, 2003-2005

Total

Cemented TKR

Cementless TKR

Unicondylar replacement

44,115

38,113

3,461

2,541

763

691

56

16

1.6% (1.5% - 1.7%)

1.7% (1.6% - 1.8%)

1.5% (1.2% - 1.9%)

0.7% (0.5% - 1.0%)

0.35(0.33 - 0.38)

0.36 (0.34 - 0.39)

0.35 (0.26 - 0.45)

0.17 (0.09 - 0.27)

Procedure type Number of procedures Deaths Rate38 (95% CI) SMR (95% CI)




Table 5.13Mortality at 1 year for primary knee replacement procedures undertaken between 1 April 2003 and 30 June 2006 that werelinked to a HES episode

39

Age

Gender


Procedure type

Providertype

< 65 years

65 - 74 years

75+ years

Male

Female



P3+ – Incapacitating systemic disease or worse



Hybrid total replacement


Patello-femoral knee replacement

NHS hospital




Factor Category Number of patients Number dying within

1 yearHazard ratio40

(95% CI)


40 Relative hazard of death within 1 year of primary knee replacementcompared to a patient with a reference level of the factor (hazard ratio=1),adjusted for all other factors included in the analyses

20,522

30,446

26,987

32,957

44,973

15,028

50,333

12,596

66,428

5,692

1,139

4,057

641

68,449

3,688

4,811

1,009

75

267

655

521

476

114

591

461

887

70

13

24

3

915

26

48

8

1.0

2.2 (1.7 - 2.9)

6.0 (4.7 - 7.6)

1.0

0.6 (0.5 - 0.7)

1.0

1.2 (1.0 - 1.5)

2.2 (1.7 - 2.7)

1.0

0.9 (0.7 - 1.2)

0.9 (0.5 - 1.6)

0.6 (0.4 - 0.9)

0.5 (0.2 - 1.6)

1.0

0.6 (0.4 - 0.8)

0.9 (0.6 - 1.1)

0.8 (0.4 - 1.6)


Table 5.14Length of hospital stay (days) following admission for a primary knee replacement for procedures linked to a HES episode41,2003 - 2006

Age

Gender


Procedure type

Providertype

< 65 years

65 - 74 years

75 - 84 years

85+ years

Male

Female




P4 – Life threatening disease



Hybrid total replacement


Patello-femoral replacement

NHS hospital




24,722

36,148

27,734

3,452

39,557

52,473

17,311

59,785

14,406

557

73,967

6,369

1,237

4,484

726

81,072

4,018

5,774

1,195

Factor Category Number of

patients

7.2 (7.2 – 7.3)

8.0 (7.9 – 8.1)

9.5 (9.4 – 9.6)

12.3 (11.9 – 12.7)

8.1 (8.0 – 8.2)

8.6 (8.6 – 8.7)

7.5 (7.4 – 7.5)

8.2 (8.1 – 8.2)

10.4 (10.1 – 10.6)

11.7 (10.6 – 12.9)

8.3 (8.2 – 8.3)

8.1 (7.9 – 8.2)

7.7 (7.5 – 8.0)

5.9 (5.8 – 6.0)

6.7 (6.5 – 7.0)

8.7 (8.6 – 8.7)

6.2 (6.0 – 6.4)

5.4 (5.3 – 5.6)

6.8 (6.7 – 6.9)

0.0

0.5 (0.4 - 0.6)

1.7 (1.6 - 1.8)

4.3 (4.0 - 4.5)

0.0

0.3 (0.3 - 0.4)

0.0

0.2 (0.1 - 0.3)

1.6 (1.5 - 1.7)

3.2 (2.7 - 3.7)

0.0

-0.03 (-0.2 - 0.1)

-0.3 (-0.6 - 0.1)

-2.1 (-2.3 _ -2.0)

-1.2 (-1.6 _ -0.8)

0.0

-2.1 (-2.2 _ -1.9)

-1.6 (-1.7 _ -1.4)

-2.7 (-3.1 _ -2.5)

Average length of stay

(days) (95% CI)Adjusted difference in average

LOS* (days) (95% CI)


Part 26. Prostheses Used in Hip and Knee Replacement Procedures



6.1 Prostheses Used in Hip Procedures

In 2006,155 different brands of acetabular cups and 176different brands of femoral stems were recorded: anincrease of 36% over 2005 for both stems and cups. This was a result of new suppliers entering the market, the introduction of new brands by existing suppliers and/or improved reporting.

6.1.1 Background

In the NJR 2nd Annual Report of 2004 (pages 86–92 availableon NJR website, www.njrcentre.org), a full description wasgiven of the National Institute for Health and Clinical Excellence(NICE) guidance on the selection of prostheses for primarytotal hip replacement and hip resurfacing arthroplasty, and the subsequent setting up of the Orthopaedic DataEvaluation Panel (ODEP).

ODEP provides an independent assessment of clinicaloutcomes data, submitted by implant manufacturers, on the compliance of brands of total hip and hip resurfacingprostheses with the NICE benchmarks for the effectivenessof primary total hip prostheses.

ODEP’s main function is to provide an independentassessment of the clinical outcomes data, submitted by manufacturers of prostheses, on the compliance ofbrands of total hip and hip resurfacing prostheses, with the NICE benchmarks for the effectiveness of primary total hip prostheses. ODEP produced criteria for assessingcompliance of products with the NICE guidance.

NICE has indicated that the situation will be reviewed in 2008.

6.1.2 Results of ODEP assessments

The ODEP committee reviewed the clinical data submissionsand as a result, 54 (40%) brands of femoral stems and 50 (49%)brands of acetabular cups received ODEP ratings. There arehowever, 52 (51%) brands of acetabular cup and 79 (60%)brands of femoral stem currently being used in England andWales for which no data has been submitted to the ODEPcommittee. Some of these may be components intended forrevision surgery and therefore not covered by the ODEPrating, but this is currently being investigated. The latestlistings for all brands currently being used by hospitals inEngland and Wales can be seen by visiting the ODEPwebsite on www.supplychain.nhs.uk/odep

6.1.3 Analysis of results

Analysis of the summary data shows that the usage ofproducts meeting the full ten year (10A) benchmark asrecommended by NICE is as follows:

• Cemented Stems: 69.0% (made up of 11 brands out of 72recorded on NJR).

• Cementless Stems: 70.6% (made up 8 brands out of 63recorded on NJR).

• Cemented Cups: 42.6% (made up 9 brands out of 51recorded on NJR).

• Cementless Cups: 4.8% (made up 1 brand out of 51recorded on NJR).

These percentages are only based on clinical outcomesdata already submitted to the ODEP committee.Manufacturers may submit additional data that could resultin these percentages being revised in the future.

Comparison with the 2005 figures shows that the usage ofcemented and cementless stems fully compliant with NICEguidelines is similar to 2006, but there has been a decline inthe usage of fully compliant cemented and cementless cups.

6.1.4 Brand sales of conventional total hipsand resurfacing prostheses

Tables 6.5 – 6.9 show the most frequently used brands inEngland and Wales during 2006, as assessed by their rate ofentry into NJR. The level of assessment according to ODEPcriteria is given in the final column.

Table 6.10 provides a summary of procedures where brands ofre-surfacing acetabular cups have been used in combinationwith a conventional stem and a large metal-on-metal femoralhead. This represents a 92% increase on last year.

6.1.5 Combinations of cups and stems

For 48,274 hip replacement procedures in the 2006 data,both the cup and stem brand was known, and a total of 776 different combinations of cup and stem brands wererecorded. This represents a 2% decrease over 2005. The combinations entered into the NJR are listed in Table 6.11.The most common cup-stem combination was the ExeterV40 stem combined with the Contemporary Duration cup.

Highlighted in Table 6.11 are those combinations where thestem manufacturer is different from the cup manufacturer – a practice known as ‘mixing and matching’. Of the 48,274procedures included in this chapter, 10,622 (22%) used‘mixed and matched’ cup-stem combinations, approximately3% fewer than in 2005 and 2004.


6.1.6 Femoral head material and size

Table 6.1 (above) shows the relative usage of differentfemoral head materials in patients of different age groups.This year, the ceramic category has been further split intoAlumina and Zirconia. The figures are very similar to those in2005 and 2004 and demonstrate that there has been nochange in surgical practice.

Table 6.2 (above right) shows the frequency of the differentfemoral head sizes. The main change compared with 2005 isan increase in the use of heads classified as ‘Other’ size andan increase in the use of 36mm heads for metal-on-metalarticulations. Over half of these ‘Other’ sized heads wereimplanted with a resurfacing cup.

6.1.7 Summary

The total number of brands of acetabular cups and femoralstems recorded in NJR has increased significantly. There are155 brands of acetabular cups (88 in 2004, 110 in 2005) and176 brands of femoral stems (101 in 2004, 129 in 2005).Although these figures show 22 new cup and 28 new stembrands, none of the brands recorded in 2004 failed to appearin 2005.

In addition to conventional re-surfacing procedures, therehave been almost 3,000 procedures entered into the NJRwhereby a re-surfacing cup has been used in conjunctionwith a large modular head and a conventional stem. Materialof femoral heads used in 2006 are very similar to 2004,however, the size of femoral heads used shows an increasein the larger head sizes ‘other head sizes’ and 32mm.

6.2 Prostheses Used in Knee Procedures

6.2.1 Prostheses entered into the NJR

54 brands of total condylar knee prostheses were recorded.In addition, there were 13 brands of unicondylar prostheses,7 brands of patello-femoral replacement prostheses and 12 brands of hinged prostheses. The number of brands foreach prosthesis type either remained the same or increasedslightly compared with 2005.

Table 6.12 shows the brands of total condylar kneereplacement prostheses recorded most frequently for TKR and hybrid procedures.

Brands of unicondylar prostheses are shown in Table 6.13. 7 brands of patello-femoral joint replacements were enteredinto the NJR in 2006 (Table 6.14). Brands of hingedprostheses entered on NJR are shown in Table 6.15.

6.2.2 Usage of fixed versus mobile bearingtibial inserts

Tibial inserts recorded in total condylar procedures werepredominantly fixed bearing (85%, 44,333) of all proceduresusing tibial inserts (an increase of 2% on 2005), comparedwith 15% (7,751) involving mobile bearing tibial inserts, asshown in Table 6.3.

MaterialNumber ofprocedures

%

47,103

Metal 35,303 75.0%

Alumina 11,645 24.7%

Zirconia 155 0.3%

Total 47,103

Table 6.1Frequency of material chosen for femoral heads inprocedures performed in 2006

Table 6.2Frequency of femoral head sizes for procedures performed in 2006

Head sizeNumber ofprocedures

%

47,127

22.25mm 1,853 3.9%

26.00mm 2,740 5.8%

28.00mm 31,636 67.2%

32.00mm 5,387 11.4%

Other size 5,511 11.7%

Total 47,127


6.3 Cement Use

The majority (92%) of procedures involving cement usedantibiotic-loaded rather than non antibiotic (Table 6.4),virtually the same as in 2004 and 2005. Manufacturers ofantibiotic-loaded cement and non-antibiotic cement aregiven in Tables 6.16 and 6.17. More than one packet ofcement could be entered for a particular procedure. Forknee procedures, between 1 and 6 packets were entered fora single procedure. For hip procedures, up to 12 packetswere entered.

6.4 Bone Substitute Use

Table 6.18 lists the manufacturers of bone substitutes for hipand knee procedures in 2006. Although the use of syntheticbone substitute remained relatively low, such products werereported as being used in 494 procedures during 2006,nearly 10% more than 2005 and almost three times as manyas in 2004.

One or two units of bone substitute were recorded for asingle knee procedure, whilst up to 5 packets were enteredfor a hip procedure.

Table 6.3Tibial insert type 2006

Table 6.4Type of cement used in hip and knee replacement procedure cement entered into NJR in 2006

Tibial insert type All patients %

52,084

Fixed Bearing 44,333 85.1%

Mobile Bearing 7,751 14.9%

52,084

Cement type Hip procedures %Knee

procedures% All procedures %

38,758 50,416 89,174

Antibiotic 34,508 89.0% 47,783 94.8% 82,291 92.3%

Non Antibiotic 4,250 11.0% 2,633 5.2% 6,883 7.7%

38,758 n/a 50,416 n/a 89,174 n/a


Table 6.5Cemented cup brands entered during 2006 for hip replacements

Stryker Howmedica Osteonics

DePuy

DePuy


DePuy

DePuy

Zimmer

Smith & Nephew

Zimmer

DePuy

DePuy

Corin

Biomet

Biomet

Biomet


Joint Replacement Instrumentation Ltd

Zimmer

Waldemar Link

Smith & Nephew

Waldemar Link

Biomet

Zimmer

Endo Plus (UK) Limited

Biomet

B Braun / Aesculap

Zimmer

Zimmer

Mathys Orthopaedics Ltd

Implants International

Biomet

Waldemar Link

Corin

Smith & Nephew

DePuy

Corin

Orthodynamics/Symbios


Zimmer

Zimmer

Biomet


CONTEMPORARY

ELITE PLUS OGEE

CHARNLEY CEMENTED CUP

EXETER DURATION

CHARNLEY OGEE

ELITE PLUS CEMENTED CUP

ZCA

OPERA

LOW PROFILE MULLER

WROBLESKI GOLF BALL

ULTIMA CEMENTED CUP

CENATOR CEMENTED CUP

STANMORE-ARCOM

APOLLO

M2A CEMENTED CUP

ODC

FURLONG CEMENTED CUP

ZIMMER CEMENTED CUP

LINK FLANGE CUP

REFLECTION CEMENTED

INTERPLANTA

ARCOM SHP

METASUL-WEBER

PE-PLUS

BIOMET MULLER

CHIRULEN

CENTERPULSE MULLER

METASUL-MULLER

CCB MATHYS

EDINBURGH CUP

CMK CEMENTED CUP

SNAP FIT

HI-NEK CEMENTED CUP

SP3

ELITE PLUS FLANGED

CTI CEMENTED CUP

ORTHODYNAMICS

EXETER CEMENTED CUP

SPC

HEDROCEL ELLIPTICAL

MAINSTREAM MULLER CEMENTED CUP

CCB

25,690

5,734

4,035

2,145

2,083

1,973

1,969

1,129

1,102

831

504

498

489

391

384

356

356

354

231

160

146

126

122

87

50

47

42

41

35

35

34

33

29

25

24

17

11

11

10

8

5

4

4

22.3%

15.7%

8.3%

8.1%

7.7%

7.7%

4.4%

4.3%

3.2%

2.0%

1.9%

1.9%

1.5%

1.5%

1.4%

1.4%

1.4%

0.9%

0.6%

0.6%

0.5%

0.5%

0.3%

0.2%

0.2%

0.2%

0.2%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

5A

10A

10A

10A

10A

5B

7A

5B

Unclassified

3B

7A

3A

10A

Pre-entry

Pre-entry

Unclassified

10B

7B

Unclassified

10A

10A

5B

3A

10C

5B

Unclassified

Unclassified

Unclassified

10A

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

5B

Unclassified

7B

10A

Unclassified

Unclassified

Unclassified

Unclassified

Manufacturer Brand Total procedures

% ODEP rating




Biomet

DePuy

Ortho-ID

Biomet

Finsbury

Corin

DePuy

Sovereign Medical

Total

MARATHON

ETERNITY CEMENTED CUP

HYLAMER OGEE

POLAR CEMENTED CUP

HEDROCEL ELLIPTICAL

FREEMAN CUP FINSBURY

METALOK CEMENTED CUP

ENDURANCE CEMENTED CUP

BICANA CUP

4

3

3

3

2

2

1

1

1

25,690

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

10C

Unclassified

Unclassified

Unclassified


% ODEP rating


Table 6.6Cementless cup brands entered during 2006 for hip replacements

DePuy


Zimmer


DePuy


Smith & Nephew


Biomet

Zimmer

Zimmer


B Braun / Aesculap

Biomet



Wright Medical UK Ltd


Biomet

Zimmer

Surgicraft


Amplitude


Biomet

Corin

Waldemar Link


Finsbury


Biomet

DePuy

Zimmer

DePuy


Biomet


DePuy

Biomet

Biomet

Waldemar Link

DePuy


PINNACLE

TRIDENT

TRILOGY

CSF

DURALOC CEMENTLESS CUP

EPF-PLUS

REFLECTION CEMENTLESS

ABG II CEMENTLESS CUP

EXCEED

ALLOFIT

TRABECULAR METAL CEMENTLESS CUP

FURLONG CEMENTLESS CUP

PLASMACUP CEMENTLESS CUP

MALLORY-HEAD CEMENTLESS CUP

SECURE FIT CEMENTLESS CUP

BICON-PLUS

ANCAFIT CEMENTLESS CUP

POLAR CEMENTLESS CUP

ALIZE

CLS CEMENTLESS CUP

SPLIT CUP

LINEAGE

SATURNE

MATHYS CEMENTLESS CUP

BIHAPRO

DC-FIT

MCMINN

SELEXYS

SLF CEMENTLESS CUP (FINSBURY)

PROCOTYL

UNIVERSAL II

J-LOC

FITMORE

S-ROM CEMENTLESS CUP

FRF

BIOMEX

MATHYS CEMENTLESS CUP

ULTIMA CEMENTLESS CUP

M2A CEMENTLESS CUP

PAR 5 RINOWL CEMENTLESS CUP

PRESSFIT

OCTOPUS

BOFOR

24,979

5,698

4,764

4,234

3,485

1,192

855

768

749

499

356

304

284

262

209

149

148

146

143

75

66

65

60

50

49

45

42

37

30

29

29

24

23

22

18

18

12

7

6

4

4

4

2

2

22.8%

19.1%

17.0%

14.0%

4.8%

3.4%

3.1%

3.0%

2.0%

1.4%

1.2%

1.1%

1.0%

0.8%

0.6%

0.6%

0.6%

0.6%

0.3%

0.3%

0.3%

0.2%

0.2%

0.2%

0.2%

0.2%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

3A

3A

7A

10B

10A

3A

7B

3A

3A

5A

Pre-entry

10B

Unacceptable

5B

5A

7A

3A

Unclassified

7B

10C

Unclassified

Pre-entry

3B

Pre-entry

7B

Unclassified

Unclassified

Unclassified

10C

Unclassified

Unacceptable

Unclassified

7B

3A

3A

Pre-entry

Unclassified

3A

Pre-entry

Unclassified

Unclassified

Unclassified

Unclassified


% ODEP rating





Waldemar Link

Biomet





Total

RM CEMENTLESS CUP (IMPLANT INTERNATIONAL)

NOVAE STICK

DAVIS CEMENTLESS CUP

RANAWAT/BURSTEIN

RM CEMENTLESS CUP (MATHYS)

NOVAE

RESTORATION GAP2

TRANSCEND

2

2

2

1

1

1

1

1

24,979

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

Unclassified

Unclassified

Unclassified

Unclassified

10B

Unclassified

Unclassified

Unclassified


% ODEP rating


Table 6.7Cemented stem brands entered during 2006 for hip replacements


DePuy

DePuy

Zimmer

Biomet

Zimmer

Biomet

Waldemar Link

DePuy


Zimmer

Zimmer

Zimmer

Smith & Nephew


Zimmer

Zimmer

DePuy

Corin

Smith & Nephew

Corin

Zimmer

DePuy

Biomet

Biomet

Biomet

Biomet

Waldemar Link

B Braun / Aesculap

Finsbury

Biomet

B Braun / Aesculap

Biomet

Zimmer


Zimmer



Corin

Biomet

Corin

Corin

Zimmer

EXETER

C-STEM CEMENTED STEM

CHARNLEY CEMENTED STEM

CPT

STANMORE MODULAR

MS-30

TAPERLOC CEMENTED STEM

SP II CEMENTED STEM

ELITE PLUS CEMENTED STEM

FURLONG CEMENTED STEM

ZMR CEMENTED STEM

MULLER STR STEM

P10 MULLER

SPECTRON

CPS-PLUS

VERSYS CEMENTED STEM

MEM

ULTIMA CEMENTED STEM

TAPERFIT CEMENTED STEM

CPCS

OXFORD UNIVERSAL HIP (CORIN) CEMENTED STEM

REVITAN CEMENTED STEM

SUMMIT CEMENTED STEM

OLYMPIA

BIMETRIC CEMENTED STEM

MODULAR INTERLOC

MONOBLOC STANMORE

MP NECK CEMENTED STEM

CENTRAMENT

ADEPT CEMENTED STEM

AURA II CEMENTED STEM

BICONTACT CEMENTED STEM

CMK CEMENTED STEM

THRUST PLATE

EDINBURGH

MAYO CEMENTED STEM

CCA CEMENTED STEM

PROFEMUR CEMENTED STEM

TRIFIT CEMENTED STEM

OXFORD UNIVERSAL HIP (BIOMET) CEMENTED STEM

CENATOR CEMENTED STEM

HI-NEK CEMENTED STEM

VERSYS HERITAGE

33,637

17,743

3,816

3,739

2,820

643

516

452

389

384

299

251

238

174

170

168

156

144

141

133

125

84

84

83

78

70

64

54

53

49

41

38

36

34

29

27

26

25

25

23

22

21

21

19

52.7%

11.3%

11.1%

8.4%

1.9%

1.5%

1.3%

1.2%

1.1%

0.9%

0.7%

0.7%

0.5%

0.5%

0.5%

0.5%

0.4%

0.4%

0.4%

0.4%

0.2%

0.2%

0.2%

0.2%

0.2%

0.2%

0.2%

0.2%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

10A

7B

10A

7A

10A

5B

Unclassified

10A

5A

10C

Unclassified

10A

10A

10A

3A

3A

10A

10C

5B

Pre-entry

Unclassified

Unclassified

Pre-entry

5B

10A

Unclassified

10A

Unclassified

3B

Pre-entry

Pre-entry

10C

10C

Unclassified

Unclassified

Unclassified

10A

Pre-entry

Unclassified

Unclassified

3A

Unclassified

Pre-entry


% ODEP rating




B Braun / Aesculap

Corin

DePuy

Corin

Finsbury

Biomet

DePuy

B Braun / Aesculap



B Braun / Aesculap

DePuy

Smith & Nephew

Van Straten Medical

Waldemar Link

Van Straten Medical

Biomet




B Braun / Aesculap

DePuy

DePuy



Smith & Nephew

Stanmore Implants Worldwide

Total

SLR-PLUS CEMENTED STEM

PREVISION CEMENTED STEM

CTI CEMENTED STEM

WROBLESKI RESECTION

CENTRAFIX

FREEMAN CEMENTED FINSBURY

KENT HIP

HOWSE II

EXCIA-CEMENTED

LMT

GMRS

HUCKSTEP CEMENTED STEM

ENGAGE

TRI TAPER CEMENTED STEM

CUSTOM DEVICE

MEGA SYSTEM

ECOFIT

MALLORY-HEAD CEMENTED STEM

ENDOPLUS CEMENTED

CANNULOK CEMENTED STEM

ACCOLADE CEMENTED

METHA CEMENTED

CHARNLEY EVOLUTION CEMENTED STEM

LPS

AJS

MARATHON CEMENTED STEM

ECHELON CEMENTED STEM

STANMORE MODULAR

17

12

12

9

8

7

6

6

5

5

5

4

4

4

4

4

3

2

2

2

2

1

1

1

1

1

1

1

33,637

0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

10C

Unclassified

Unclassified

Unclassified

7B

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified


% ODEP rating


Table 6.8Cementless stem brands entered during 2006 for hip replacements

DePuy



Smith & Nephew



Zimmer


Zimmer

Biomet

DePuy

Biomet

Biomet


DePuy

DePuy

B Braun / Aesculap

DePuy

Biomet

Finsbury

Waldemar Link

Smith & Nephew

DePuy



DePuy

Zimmer


Zimmer

Biomet


Corin

Biomet

Corin

DePuy

Corin

DePuy


Smith & Nephew

B Braun / Aesculap

Smith & Nephew

Corin

Biomet

CORAIL

FURLONG HAC

SL-PLUS CEMENTLESS STEM

SYNERGY CEMENTLESS STEM

ABG II CEMENTLESS STEM

OMNIFIT CEMENTLESS STEM

CLS CEMENTLESS STEM

ACCOLADE

VERSYS CEMENTLESS STEM

BIMETRIC CEMENTLESS STEM

S-ROM CEMENTLESS STEM

MAINSTREAM MULLER CEMENTLESS STEM

TAPERLOC CEMENTLESS STEM

PROFEMUR CEMENTLESS STEM

SUMMIT CEMENTLESS STEM

KAR

BICONTACT CEMENTLESS STEM

SOLUTION CEMENTLESS STEM

AURA II CEMENTLESS STEM

FREEMAN CEMENTLESS

DAVIES CEMENTLESS STEM

ECHELON CEMENTLESS STEM

REEF

ANCAFIT CEMENTLESS STEM

CANNULOK CEMENTLESS STEM

AML

ZWEYMULLER

RESTORATION CEMENTLESS STEM

ALLOCLASSIC CEMENTLESS STEM

BIHAPRO MK III

CBC

PROXIMA

CONELOCK

C FIT

IPS

PANATOMIC CEMENTLESS STEM

PROXIMA

TWINSYS CEMENTLESS STEM

BIRMINGHAM HEAD RESECTION STEM

EXCIA

ANTHOLOGY

TRIFIT CEMENTLESS STEM

MALLORY-HEAD CEMENTLESS STEM

18,506

6,038

3,807

1,061

825

757

756

591

558

538

509

428

396

332

279

232

143

100

96

86

84

81

79

76

76

65

64

55

52

50

34

29

26

22

21

19

16

14

14

14

13

12

9

5

32.6%

20.6%

5.7%

4.5%

4.1%

4.1%

3.2%

3.0%

3.0%

2.8%

2.3%

2.1%

1.8%

1.5%

1.3%

0.8%

0.5%

0.5%

0.5%

0.5%

0.4%

0.4%

0.4%

0.4%

0.4%

0.3%

0.3%

0.3%

0.3%

0.2%

0.2%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

<0.1%

<0.1%

10A

10A

10A

5A

5B

10A

10A

3B

3A

10A

7B

Pre-entry

10B

Pre-entry

3A

Unclassified

10C

Unclassified

Pre-entry

10C

Unclassified

Unclassified

Unclassified

3A

Unclassified

10B

10A

Unclassified

10A

7B

Pre-entry

5A

Unclassified

Unclassified

5A

Unclassified

Unclassified

Pre-entry

Unclassified

3A

Unclassified

Unclassified

10B

Manufacturer Brand Total Procedures

% ODEP rating



International Orthopaedics Ltd


Waldemar Link

Zimmer


Surgicraft

Zimmer

Biomet

Corin



Zimmer

B Braun / Aesculap

B Braun / Aesculap

Corin

DePuy



Zimmer

Total

HACTIV

ABG I CEMENTLESS STEM

CFP

WAGNER CONE

CALCAR REP

ESOP

ANATOMIC

REACH

HI-NEK CEMENTLESS STEM

BRADLEY

GMRS CEMENTLESS

MAYO CEMENTLESS STEM

HUCKSTEP CEMENTLESS STEM

METHA

ALPHA FIT

REPLICA

ENDOPLUS CEMENTLESS HIP

ENDOPLUS CEMENTLESS REVISION STEM

ZMR CEMENTLESS STEM

5

5

4

4

3

3

3

2

2

2

2

2

1

1

1

1

1

1

1

18,506

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

Pre-entry

7A

Unclassified

3B

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

5A

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified

Unclassified


% ODEP rating


Table 6.9Brands of resurfacing heads entered into the NJR in 2006

Smith & Nephew

Corin

DePuy

Zimmer


Finsbury

Biomet


International Orthopaedics Ltd

Van Straten Medical

Tricon/Medacta

Total

BHR RESURFACING HEAD

CORMET 2000 RESURFACING HEAD

ASR RESURFACING HEAD

DUROM RESURFACING HEAD

CONSERVE

ADEPT RESURFACING HEAD

RECAP RESURFACING HEAD

MITCH TRH

ICON

ACCIS RESURFACING HEAD

CORNWALL RESURFACING HEAD

6,314

3,288

819

819

426

367

292

196

41

32

24

10

6,314

52.1%

13.0%

13.0%

6.7%

5.8%

4.6%

3.1%

0.6%

0.5%

0.4%

0.2%

7A

3A

Pre-entry

Pre-entry

3A

Pre-entry

Pre-entry

Pre-entry

Pre-entry

Unclassified

Pre-entry


% ODEP rating


Table 6.10Procedures using a resurfacing cup with a conventional stem in 2006

DePuy

Smith & Nephew

Zimmer

Biomet

Finsbury

Corin

Midland Medical Technologies Ltd



Tricon/Medacta

Total

ASR RESURFACING CUP

BHR RESURFACING CUP

DUROM RESURFACING CUP

RECAP RESURFACING CUP

ADEPT RESURFACING CUP

CORMET 2000 RESURFACING CUP

BHR RESURFACING CUP

CONSERVE PLUS

MITCH TRH CUP

ESKA RESURFACING CUP

2,856

924

496

397

392

299

281

49

13

4

1

2,856

32.4%

17.4%

13.9%

13.7%

10.5%

9.8%

1.7%

0.5%

0.1%

<0.1%


%


Table 6.11Top 20 Cup - Stem combinations recorded in the NJR in 2006

Stryker HowmedicaOsteonics

DePuy

Joint ReplacementInstrumentation Ltd




DePuy

DePuy


Zimmer

DePuy

Zimmer

DePuy


DePuy



DePuy

Zimmer

DePuy

EXETER V40

CORAIL

FURLONG HAC

EXETER V40

EXETER V40

EXETER V40

CHARNLEY CEMENTEDSTEM

CHARNLEY CEMENTEDSTEM

EXETER V40

CPT

C-STEM CEMENTEDSTEM

CPT

C-STEM CEMENTEDSTEM

EXETER V40

CORAIL

SL-PLUS CEMENTLESSSTEM

ACCOLADE

C-STEM CEMENTEDSTEM

VERSYS CEMENTLESSSTEM

C-STEM CEMENTEDSTEM


DePuy

Joint ReplacementInstrumentation Ltd


DePuy


DePuy

DePuy

Zimmer

Zimmer

DePuy

Zimmer

DePuy

DePuy

DePuy



Smith & Nephew

Zimmer

DePuy

CONTEMPORARY

PINNACLE

CSF

TRIDENT

ELITE PLUS OGEE

EXETER DURATION

CHARNLEY CEMENTEDCUP

CHARNLEY OGEE

TRILOGY

TRILOGY

ELITE PLUS OGEE

ZCA

ELITE PLUS CEMENTEDCUP

ELITE PLUS CEMENTEDCUP

DURALOC CEMENTLESSCUP

EPF-PLUS

TRIDENT

OPERA

TRILOGY

PINNACLE

Other

Other

5,505

4,147

3,139

2,766

2,202

1,980

1,687

1,484

1,369

993

956

933

841

700

682

595

560

449

431

399

10,544

5,902

11.4%

8.6%

6.5%

5.7%

4.6%

4.1%

3.5%

3.1%

2.8%

2.1%

2.0%

1.9%

1.7%

1.5%

1.4%

1.2%

1.2%

0.9%

0.9%

0.8%

21.8%

12.2%

No

No

No

No

Yes

No

No

No

Yes

No

No

No

No

Yes

No

No

No

Yes

No

No

No

Yes

Stem manufacturer Stem brand Cup manufacturer Cup Brand Number ofprocedures

%

48,264

Mix andmatch?


Table 6.12Total Condylar knee brands entered into NJR in 2006 for total knee replacements and hybrid and revision procedures

DePuy

Zimmer

Biomet


Smith & Nephew


DePuy


Smith & Nephew


Biomet

Finsbury



Corin

Zimmer

Exactech (UK) Ltd

B Braun / Aesculap

Zimmer

Zimmer

Biomet

Van Straten Medical

B Braun / Aesculap

Biomet

Zimmer

Corin

Biomet

Waldemar Link

Smith & Nephew


Finsbury

Biomet

Smith & Nephew

Corin


Sovereign Medical


Orthopaedic Surgical Implants Ltd

Intavent - Orthofix


Smith & Nephew

Smith & Nephew

Zimmer

PFC SIGMA BICONDYLAR KNEE

NEXGEN

AGC

SCORPIO

GENESIS 2

ENDOPLUS BICONDYLAR KNEE

LCS

KINEMAX

PROFIX

ADVANCE BICONDYLAR KNEE

MAXIM

MRK

INSALL-BURSTEIN 2

TRIATHLON

ROTAGLIDE +

NK2 BICONDYLAR KNEE

OPTETRAK

COLUMBUS

INSAL-BURSTEIN 2

FS

VANGUARD

CCI

E-MOTION BICONDYLAR KNEE

CKS

INNEX

ROTAGLIDE

ALPINA

TACK

LEGION

JRI BICONDYLAR KNEE

DBK

OXFORD TMK

JOURNEY

AMC

ST LEGER

CCI

ADVANTIM

ACTIVE BICONDYLAR KNEE

OPTETRAK

TC PLUS

GENESIS

RENASYS BICONDYLAR KNEE

SAL

52,099

18,198

6,881

6,429

4,823

2,610

2,517

2,081

2,048

1,043

729

517

499

461

426

425

402

368

230

159

148

140

134

132

103

89

77

71

65

45

44

34

31

22

21

17

16

15

11

6

5

4

4

3

34.9%

13.2%

12.3%

9.3%

5.0%

4.8%

4.0%

3.9%

2.0%

1.4%

1.0%

1.0%

0.9%

0.8%

0.8%

0.8%

0.7%

0.4%

0.3%

0.3%

0.3%

0.3%

0.3%

0.2%

0.2%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%


%



DePuy

DePuy


Zimmer

Amplitude

Biomet

Biomet

Finsbury



Total

AMK

PFC BICONDYLAR KNEE

AVANCE

NATURAL KNEE

SCORE

RHK

ROCC

FS 1000

MATHYS BICONDYLAR KNEE

913 SYSTEM

3

3

2

2

1

1

1

1

1

1

52,099

<0.1%

<0.1%

v

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%


%

Biomet

Zimmer

DePuy

Corin

Waldemar Link


Smith & Nephew



Biomet

B Braun / Aesculap


Biomet

Total

OXFORD III

MG UNI

PRESERVATION

ACM/UNIGLIDE

SLED

EUIS

GENESIS UNI

UC-PLUS

MATHYS UNICONDYLAR KNEE

OXFORD UNI

E-MOTION UNICONDYLAR KNEE

ADVANCE UNICONDYLAR KNEE

REPICCI

5,338

3,895

548

290

199

126

116

73

46

29

6

5

4

1

5,338

73.0%

10.3%

5.4%

3.7%

2.4%

2.2%

1.4%

0.9%

0.5%

0.1%

0.1%

0.1%

<0.1%

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

Yes

No

No

Yes

No

No

Yes

No

Yes

No

Yes

Yes

Yes


% Cemented Cementless

Table 6.13Unicondylar knee brands entered into the NJR in 2006 for unicondylar knee procedures


Table 6.14Patello-femoral joint brands entered into the NJR in 2006 for patello-femoral joint replacement procedures



Smith & Nephew

Waldemar Link

Corin


Biomet

Total

AVON

FPV

COMPETITOR

LUBINUS PF

LEICESTER

WRIGHT MEDICAL PF

PERFORMANCE PF

495

357

85

37

7

4

4

1

495

72.1%

17.2%

7.5%

1.4%

0.8%

0.8%

0.2%


%

Table 6.15Fixed and rotating hinged knee brands 2006

Waldemar Link


Zimmer

DePuy

Biomet

Biomet


Stanmore Implants Worldwide

Waldemar Link

Waldemar Link

Biomet


Total

ENDO ROTATING HINGE

MRH

NEXGEN HINGE TYPE

NOILES

BIRMINGHAM ROT HINGE

STANMORE HINGE

RT PLUS

SMILES HINGED/LINKED KNEE

MC

ENDO HINGE

OSS

GUARDIAN HINGED/LINKED KNEE

677

236

145

113

76

36

25

12

12

8

6

4

4

677

34.9%

21.4%

16.7%

11.2%

5.3%

3.7%

1.8%

1.8%

1.2%

0.9%

0.6%

0.6%


%


Table 6.16Brands of antibiotic bone cement entered into the NJR in 2006

Schering-Plough

Heraeus Medical

DePuy


Biomet

DePuy

Heraeus Medical

Heraeus Medical

Biomet

Biomet

DePuy

Biomet

DePuy

Smith and Nephew

Total

PALACOS ANTIBIOTIC

PALACOS ANTIBIOTIC

CMW ANTIBIOTIC LOADED CEMENT

SIMPLEX ANTIBIOTIC

PALACOS ANTIBIOTIC

CMW BONE CEMENT

PALACOS ANTIBIOTIC

PALAMED

OSTEOPAL ANTIBIOTIC

CMW ANTIBIOTIC LOADED CEMENT

SMARTSET/ENDURANCE

OPTIVAC REGULAR

CEMVAC ANTIBIOTIC LOADED CEMENT

WRIGHT MEDICAL BONE CEMENT

103,540

32,563

30,903

13,723

12,412

11,195

1,539

921

95

91

40

38

15

4

1

103,540

31.4%

29.8%

13.3%

12.0%

10.8%

1.5%

0.9%

0.1%

0.1%

<0.1%

<0.1%

<0.1%

<0.1%

<0.1%

Manufacturer Brand Number %

Table 6.17Brands of non-antibiotic bone cement entered into the NJR in 2006


Schering-Plough

DePuy

Biomet

Heraeus Medical

DePuy

Corin

Biomet

Zimmer


Total

SIMPLEX

PALACOS

CMW BONE CEMENT

PALACOS

PALACOS

SMARTSET

CORIPLAST

OSTEOPAL

SULCEM

SULCEM

8,676

3,456

2,206

1,411

1,196

231

86

57

30

2

1

8,676

39.8%

25.4%

16.3%

13.8%

2.7%

1.0%

0.7%

0.3%

<0.1%

<0.1%



Table 6.18Brands of synthetic bone substitute entered into the NJR in 2006




Synthes

ApaTech Products

Corin


Synthes



DePuy


Biomet

Surgicraft

DePuy


Quadrant Medical Ltd

Total

ENDOPLUS BONE SUBSTITUTE

BONESAVE

OSTEOSET

DBX

APATECH BONE SUBSTITUTE

BIOFUSE

ALLOGRAN (ENDOPLUS)

SYNTHES BONE SUBSTITUTE

STIMULAN (ENDOPLUS)

SCORPIO

CONDUIT

JRI BONE SUBSTITUTE

ENDOBON

SURGICRAFT

GRAFTON

B-GRAN

CORTOSS

494

266

88

34

27

20

16

8

8

6

6

4

4

2

2

1

1

1

494

53.8%

17.8%

6.9%

5.5%

4.0%

3.2%

1.6%

1.6%

1.2%

1.2%

0.8%

0.8%

0.4%

0.4%

0.2%

0.2%

0.2%


Part 2Appendices



Pre

-ent

ry b

ench

mar

kp

rod

ucts

Pro

duct

s th

at d

o no

tm

eet t

he b

ench

mar

ksh

ould

onl

y be

use

d as

part

of a

clin

ical

tria

l

Ent

rybe

nchm

ark

Man

ufac

ture

rs a

rere

ques

ted

to k

eep

OD

EP

info

rmed

of

all c

omm

erci

ally

avai

labl

e pr

osth

eses

that

are

invo

lved

inpo

stm

arke

t clin

ical

follo

w-u

p st

udie

s.(T

his

need

not

incl

ude

prod

ucts

still

in d

evel

opm

ent)

The

deta

ils s

houl

dco

nsis

t of:

Num

ber

of c

entr

es

Num

ber

of s

urge

ons

Num

ber

of p

atie

nts

Met

hodo

logy

of s

tudy

All

UK

impl

antin

gce

ntre

s id

entif

ied

OD

EP

will

then

list

thes

e pr

oduc

ts fo

rsu

rgeo

ns’ i

nfor

mat

ion

3 ye

ars

Leve

l A –

Acc

epta

ble

evi

den

ce

• Fa

ilure

rat

e of

3%

or

less

• K

apla

n M

eier

sur

vivo

rshi

psu

bmitt

ed

• 95

% c

onfid

ence

inte

rval

s to

incl

ude

benc

hmar

k

• A

ll U

K im

plan

ting

cent

res

iden

tifie

d

• A

ll pr

oduc

t fai

lure

s id

entif

ied

• A

list

pro

vide

d of

all

stud

ies

(pub

lishe

d or

unp

ublis

hed)

incl

udin

g al

l ini

tiate

d by

the

man

ufac

ture

r

• A

ll E

nglis

h an

d W

elsh

dat

a no

wbe

ing

ente

red

into

NJR

Leve

l B –

Wea

k ev

iden

ce

• A

ccep

tabl

e fa

ilure

rat

e

• S

tudy

res

ults

sub

mitt

ed

• Fa

ilure

s id

entif

ied

5 ye

ars

Leve

l A –

Acc

epta

ble

evi

den

ce

• Fa

ilure

rat

e of

5%

or

less

• K

apla

n M

eier

sur

vivo

rshi

p su

bmitt

ed

• 95

% c

onfid

ence

inte

rval

s to

incl

ude

benc

hmar

k

• A

ll U

K im

plan

ting

cent

res

iden

tifie

d

• D

ata

beyo

nd d

evel

opin

g ce

ntre

sub

mitt

ed

• A

list

pro

vide

d of

all

stud

ies

(pub

lishe

d or

unp

ublis

hed)

in

clud

ing

all i

nitia

ted

by th

em

anuf

actu

rer

• A

ll E

nglis

h an

d W

elsh

dat

a no

wbe

ing

ente

red

into

NJR

Leve

l B –

Wea

k ev

iden

ce

• A

ccep

tabl

e fa

ilure

rat

e

• S

tudy

res

ults

sub

mitt

ed

• Fa

ilure

s id

entif

ied

7 ye

ars

Leve

l A –

Acc

epta

ble

evi

den

ce

• Fa

ilure

rat

e of

7%

or

less

• K

apla

n M

eier

sur

vivo

rshi

p su

bmitt

ed

• 95

% c

onfid

ence

inte

rval

s to

incl

ude

benc

hmar

k

• A

ll U

K im

plan

ting

cent

res

iden

tifie

d

• D

ata

beyo

nd d

evel

opin

g ce

ntre

/ssu

bmitt

ed

• A

list

pro

vide

d of

all

stud

ies

(pub

lishe

d or

unp

ublis

hed)

in

clud

ing

all i

nitia

ted

by th

em

anuf

actu

rer

• A

ll E

nglis

h an

d W

elsh

dat

a no

wbe

ing

ente

red

into

NJR

Leve

l B –

Wea

k ev

iden

ce

• A

ccep

tabl

e fa

ilure

rat

e

• S

tudy

res

ults

sub

mitt

ed

• Fa

ilure

s id

entif

ied

10 y

ears

Leve

l A –

Str

ong

evi

den

ce

• Fa

ilure

rat

e of

10%

or

less

• C

ohor

t of m

ore

than

500

join

ts a

t sta

rt o

f stu

dy

• A

ll pr

oduc

t fai

lure

s id

entif

ied

• K

apla

n M

eier

sur

vivo

rshi

p at

10

year

s on

ac

cept

able

siz

e co

hort

• R

egis

try

data

or

mul

ticen

tre

(3 o

r m

ore

cent

res

incl

udin

g no

n de

velo

ping

)

Leve

l B –

Rea

sona

ble

evi

den

ce

• Fa

ilure

rat

e of

10%

or

less

• M

ultic

entr

e (m

ore

than

one

) da

ta s

ubm

itted

• D

ata

beyo

nd d

evel

opin

g ce

ntre

/s s

ubm

itted

Leve

l C –

Wea

k ev

iden

ce

(pro

duct

s gi

ven

two

year

s to

impr

ove

data

or

they

are

dee

med

una

ccep

tabl

e)

• Fa

ilure

rat

e of

10%

or

less

• S

tudy

res

ults

sub

mitt

ed

Ent

ry b

ench

mar

k

Una

ccep

tabl

e ev

iden

ceU

nacc

epta

ble

evid

ence

Una

ccep

tabl

e ev

iden

ceU

nacc

epta

ble

evid

ence

Full

ben

chm

ark

App

endi

x 1

– A

sses

smen

t Crit

eria

for T

otal

Hip

Pro

sthe

ses

Util

ised

by

the

Orth

opae

dic

Dat

a E

valu

atio

n Pa

nel (

OD

EP

)

Glossary



Acetabular component

A

The portion of a total hip replacement prosthesis that is inserted into the acetabulum –the socket part of a ball and socket joint

B

Acetabular cup (hip) See Acetabular component

Acetabular prosthesis See Acetabular component

Arthroplasty A procedure where natural joint, or part of a natural joint, is replaced by an artificialprosthesis

ASA American Society of Anaesthesiology (ASA) scoring system for grading the overallphysical condition of the patient as ‘fit and healthy’, ‘mild disease, not incapacitating’,‘incapacitating system disease’ or ‘life threatening disease’

Bilateral operation Operation performed on both sides, e.g. left and right knee procedures carried outduring a single operation

Brand (of prosthesis) The brand of a prosthesis (or implant) is the manufacturer’s product name, e.g. the Charnley brand for hips, the Rotaglide Plus brand for knees

C

D

Case ascertainment Proportion of all relevant joint replacement procedures performed in England and Walesthat are entered in the NJR

Case mix Term used to describe the variation in the surgical practice in terms of factors such asindications for surgery, patient age, sex etc

Data collections periods forannual report analysis

The NJR Annual Report Part 1 is about data collected between 1 April 2006and 31 March 2007 – the 2006/07 financial year

The NJR Annual Report Part 2 analyses data on hip and knee proceduresundertaken between 1 January and 31 December 2006 inclusive – the 2006 Calendar year

Cement gun A pressurised container used to insert bone cement into bony cavities

Cement pressuriser A device used to aid surgeon in optimising the strength of adhesion between bonecement and bone

Compliance The percentage of all total joint procedures which were performed in an individual unitthat have been entered into the NJR within any given period

Cup See Acetabular component

Data quality Completeness, accuracy and linkability of NJR data

F

Femoral component (hip) Part of total hip joint that is inserted into the femur (thigh bone) of the patient. It normally consists of a stem and head (ball)

Femoral component (knee) Portion of a knee prosthesis that is used to replace the articulating surface ofthe femur (thigh bone)

Femoral head Ball shaped portion of the femur that forms part of the ball and socket hip joint


Femoral prosthesis Portion of a total joint replacement used to replace damaged parts of the femur (thighbone)

Head See Femoral head

Healthcare provider NHS or independent sector organisation that provides healthcare, in the case of theNJR, orthopaedic hip and knee replacement surgery

Hybrid procedure Joint replacement procedure where cement is used on one articulated surface and theother is cementless

Femoral stem See Femoral component (hip)

H

L

I

Image guided surgery Surgery performed by the surgeon, using real time images (normally x-rays) to help thealignment and positioning of prosthetic components

Indication (for surgery) Reason for surgery. The NJR system allows for more than one indication to be recorded

Laminar flow (in theatres) System which ensures a continuous flow of ‘clean’ air around the patient during surgicalprocedures

Levy Additional payment placed on the sales of specific hip and knee implants to cover thecosts associated with on-going operations and development of the NJR

Linkable percentage Linkable percentage is an estimate of the percentage of all relevant procedures that havebeen entered into the NJR and may be linked via NHS number to other proceduresperformed on the same patient

Linkable procedures Procedures entered into the NJR database that are linkable to a patient’s previous orsubsequent procedures by the patient’s NHS number

M

MDS Minimum data set, the set of data fields collected by the NJR. Some of the data fields aremandatory (i.e. they must be filled in). Fields that relate to patient personal details mustonly be completed where informed patient consent has been obtained

NHS National Health Service

NICE benchmark See ODEP ratings

NJR National Joint Registry for England and Wales. Since 1 April 2003, the NJR has collectedand analysed data on hip and knee replacements. It covers both the NHS andindependent healthcare sectors to ensure complete recording of national activity inEngland and Wales

MDS 1 (MDSv1) Minimum data set version one, used to collect data from 1 April 2003. MDS 1 closed tonew data entry on 1 April 2005

MDS 2 (MDSv2) Minimum data set version two, introduced on 1 April 2004. MDS 2 replaced MDS 1 asofficial data set on 1 June 2004

Minimally invasive surgery (MIS) Surgery performed using special instruments that allow very small incisions to be madein the tissues of the patient

Mixing and matching Also know as ‘cross-breeding’. Hip replacement procedure where a surgeon chooses toimplant a femoral component (incorporating a metallic or ceramic modular head) fromone manufacturer with an acetabular component (incorporating a polyethylene bearingsurface) from another

Modular Component composed of more than one piece, e.g. a modular acetabular cup shellcomponent

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NJR Centre National co-ordinating centre for the NJR

NJR StatsOnline Web facility for viewing and downloading NJR statistics on www.njrcentre.org.uk

NSTS NHS Strategic Tracing Service. Used to source missing NHS numbers and to determinewhen patients recorded on the NJR have died

ODEP Orthopaedic Data Evaluation Panel of the NHS Purchasing and Supply Agency (PASA)

ODEP ratings ODEP ratings are the criteria for prostheses for primary total hip replacement productcategorisation against NICE benchmarks. The categorisation based on the NICEbenchmarks for products – pre-entry benchmark (products commercially available thatare involved in postmarket clinical follow-up studies); entry benchmark (3 years, 5 yearsand 7 years; level A – acceptable evidence, level B – weak evidence); full benchmark (10years; level A – strong evidence, level B – reasonable evidence, level C – weakevidence). Under each year is a level that is unacceptable evidence, where productshould only be used as part of a clinical trial

PASA NHS Purchasing and Supply Agency

Patella resurfacing Replacement of the surface of the patella (knee cap) with a prosthesis

Patello-femoral knee replacement Procedure involving replacement of femoral condyles and resurfacing of the patella

Patello-femoral prosthesis (knee) Two piece knee prosthesis that provides a prosthetic articulation surface between thepatella and femoral condyles

Patient consent Patient personal details may only be submitted to the NJR where explicit informedpatient consent has been given. If a patient does not give consent only the anonymousoperation and implant data may be submitted

Patient physical status See ASA

Patient procedure Type of procedure carried out on a patient e.g. primary total prosthetic replacementusing cement

PEDW Patient Episode Database Wales, the Welsh equivalent to Hospital Episode Statistics(HES) in England

Primary hip/knee replacement First total joint replacement operation performed on any individual patient

Posterior Lipped AugmentationDevice (PLAD)

Special design of cup

Prosthesis Orthopaedic implant using joint replacement procedures, e.g. at total hip or aunicondylar knee

Pulsatile lavage Pulsed jet of sterile water used to clean the bony surfaces prior to the implantation of atotal joint replacement

Re-operation other than revision Procedures following a primary replacement that do not require component removal orreplacement

OPCS-4 Office of Population, Censuses and Surveys: Classification of Surgical Operations andProcedures, 4th Revision

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Resurfacing (hip) Resurfacing of the femoral head with a surface replacement femoral prosthesis andinsertion of an acetabular cup with or without cement

Reverse hybrid procedure (hip) Hip procedure where the acetabular prosthesis is cemented and the femoral prosthesisis not cemented

Revision hip/knee replacement Operation performed to remove and replace one or more components of a total jointprosthesis for whatever reason


Socket augmentation Dislocation of the joint

Stem See Femoral component (hip)

Surgical approach Surgical technique used by a surgeon to expose the bone prior to joint replacementwhilst minimising the damage to surrounding tissues

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TED stockings Pressurised stockings worn by patients following surgery. These help to prevent bloodclots forming in the blood vessels of the legs

THR Total hip replacement (total hip arthroplasty). Replacement of the femoral head with a stemmed femoral prosthesis and the insertion of an acetabular cup, with or without cement

Thromboprophylaxis Drug or other post-operative regime prescribed to patients with the aim of preventingblood clot formation in the postoperative period

TKR Total knee replacement (total knee arthroplasty). Replacement of both tibial and bothfemoral condyles, with or without resurfacing of the patella and with or without cement

Total condylar knee Type of knee prosthesis that replaces the complete contact area between the femur andthe tibia of a patient

Treatment centre (TC) Treatment centres are dedicated units that offer elective and short stay surgery anddiagnostic procedures in specialities such as ophthalmology, orthopaedic and a range ofother conditions. These include hip and knee replacements. Treatment centres may beNHS or privately funded

Trochanter Bony protuberance of the femur found just below the femoral head

Trochanteric osteotomy Temporary incision of the trochanter, used to aid exposure of hip joint during some typesof total hip replacement

Type (of prosthesis) Type of prosthesis is the generic description of a prosthesis e.g. modular cemented stem(hip), patella-femoral joint (knee)

Unicondylar arthroplasty Replacement of one tibial condylar and one femoral condyl, with or without resurfacingof the patella

Unicondylar knee replacement See Unicondylar arthroplasty

Unilateral operation Operation performed on one side only e.g. left hip

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NJR Centre Contact Details

National Joint RegistryNorthgate Information Solutions (UK) LtdPeoplebuilding 2Peoplebuilding EstateMaylands AvenueHemel HempsteadHertfordshire HP2 4NW

Telephone 0845 345 9991Fax 0845 345 9992Email [email protected] www.njrcentre.org.uk

www.njrcentre.org.uk

national joint registry for england and wales 4th annual report

Documents