sliding hip screw fixation for proximal femur fractures: an analysis of the predictive factors of...

SLIDING HIP SCREW FIXATION FOR SLIDING HIP SCREW FIXATION FOR PROXIMAL FEMUR FRACTURES: PROXIMAL FEMUR FRACTURES:

AN ANALYSIS OF THE PREDICTIVE AN ANALYSIS OF THE PREDICTIVE FACTORS OF FAILUREFACTORS OF FAILURE

Dr Tao Shan LimDr Tao Shan Lim MBBS Grad Dip Surg AnatMBBS Grad Dip Surg Anat

Mr Karl Stoffel Mr Karl Stoffel MDMD

Dr Rochelle Nicholls Dr Rochelle Nicholls PhDPhDDr Bianca Billik Dr Bianca Billik MBBSMBBS

Fremantle Orthopaedic UnitFremantle Orthopaedic UnitFremantle HospitalFremantle HospitalWestern AustraliaWestern Australia

The Sliding Hip ScrewThe Sliding Hip Screw

Trochanteric region #’sTrochanteric region #’s

Maximises healing potentialMaximises healing potential

Elderly / co-morbiditiesElderly / co-morbidities

FailureFailure

8 – 23% 8 – 23%

Bone qualityBone quality

Fragment geometryFragment geometry

ReductionReduction

Implant placementImplant placement

Kaufer, Clinical Orthopaedics 1980, Jan-Feb:53–61.Dodds & Baumgaertner, Current Opinion in Orthopedics 2004, Feb:12-17

Baumgaertner, 1995Baumgaertner, 1995

Tip – Apex Distance > 25mmTip – Apex Distance > 25mm

19 failures in 198 fractures (9.6%)19 failures in 198 fractures (9.6%)– 16 cut out16 cut out

Baumgaertner et al, J Bone Joint Surg Am. 1995 Jul;77(7):1058-64

Baumgaertner, 1995Baumgaertner, 1995

Tip – Apex Distance > 25mmTip – Apex Distance > 25mm

19 failures in 198 fractures (9.6%)19 failures in 198 fractures (9.6%)– 16 cut out16 cut out

5 different devices5 different devices– 142 sliding hip screw 142 sliding hip screw (3 manufacturers)(3 manufacturers)

– 56 intramedullary nail 56 intramedullary nail (2 manufacturers)(2 manufacturers)


Study AimsStudy Aims

Local experience of useLocal experience of use

– Dynamic Hip ScrewDynamic Hip Screw

– Exclusive use since March Exclusive use since March 20012001

Identify failuresIdentify failures

Identify predictive factorsIdentify predictive factors

Study DesignStudy Design

Retrospective radiological auditRetrospective radiological audit

731 cases731 cases

701 patients701 patients

2002 – 20042002 – 2004

Inclusion CriteriaInclusion Criteria

New adult proximal femur fractureNew adult proximal femur fracture

Adequate imagingAdequate imaging– PreoperativePreoperative– Implant Implant

MethodsMethods

Theatre databaseTheatre database

Ortho techsOrtho techs

PACSPACS

Revision Revision – CauseCause

PACSPACS

Picture Archiving Computer SystemPicture Archiving Computer System

Fremantle HospitalFremantle Hospital– 20012001

Sir Charles Gairdner HospitalSir Charles Gairdner Hospital– 20042004

Royal Perth HospitalRoyal Perth Hospital– 20042004

Fracture ClassificationFracture Classification

AO / MullerAO / Muller

Evan’sEvan’s

Müller et al; Manual of internal fixation: techniques recommended by the AO-ASIF group, ed 3, Berlin, 1991, Springer-Verlag

Fracture ClassificationFracture Classification

AO / MullerAO / Muller

Evan’sEvan’s

Evan E. J Bone Joint Surg 1949;31B:190–203

X-raysX-rays

1. Reduction1. Reduction Alignment APAlignment AP

Normal or slight valgusNormal or slight valgus

Alignment LateralAlignment Lateral

Less than 20 degrees tilt Less than 20 degrees tilt of femoral headof femoral head

X-raysX-rays

1. Reduction1. Reduction DisplacementDisplacement

Less than 5mm Less than 5mm displacement of any displacement of any bone fragmentbone fragment

X-raysX-rays

1. Reduction1. Reduction

2. Tip – Apex 2. Tip – Apex DistanceDistance


X-raysX-rays

1. Reduction1. Reduction

2. Tip – Apex 2. Tip – Apex DistanceDistance

3. Position of screw 3. Position of screw in femoral headin femoral head

Cleveland et al, J Bone Joint Surg Am. 1959 Dec;41-A:1399-408

Exclusion CriteriaExclusion Criteria

Not a fractureNot a fracture– 1 case (myeloma)1 case (myeloma)

Inadequate imagingInadequate imaging– 11 cases11 cases

DemographicsDemographics

387 Females, 120 Males387 Females, 120 Males– Female : Male 2.79 : 1Female : Male 2.79 : 1

Mean age 80.9 years Mean age 80.9 years – Range 15.0 – 106.2 Range 15.0 – 106.2 – SD 13.0SD 13.0

AgeAge

Above 9080-9070-8060-7050-60Below 50

AgeStrat_6

50.0%

40.0%

30.0%

20.0%

10.0%

0.0%

Per

cent

21%

43%

23%

6%3%3%

ASA ScoreASA Score

54321

ASA

60.0%

50.0%

40.0%

30.0%

20.0%

10.0%

0.0%

Per

cent

0%

12%

58%

24%

6%

Radiological Follow UpRadiological Follow Up

Intraoperative onlyIntraoperative only 25.3%25.3%

Postoperative X-ray within 2 weeksPostoperative X-ray within 2 weeks 33.8%33.8%

X-ray between 2 weeks and 3 monthsX-ray between 2 weeks and 3 months 17.9%17.9%

X-ray after 3 monthsX-ray after 3 months 23.0%23.0%

SurgeonSurgeon

ConsultantConsultant 10.7%10.7% 41 min41 min

FellowFellow 1.8%1.8% 43 min43 min

Training registrarTraining registrar 50.6%50.6% 39 min39 min

Service registrarService registrar 36.9%36.9% 50 min50 min

SurgeonSurgeon

ConsultantConsultant 10.7%10.7% 41 min41 min

FellowFellow 1.8%1.8% 43 min43 min

Training registrarTraining registrar 50.6%50.6% 39 min39 min

Service registrarService registrar 36.9%36.9%50 min50 min

PP < 0.001 < 0.001

Fracture RegionFracture Region

22.4% 22.4% 76.3% 1.2%76.3% 1.2%

N = 164 N = 164 N = 407 N = 9N = 407 N = 9

Trochanter Trochanter vs Neckvs Neck

AgeAge

(years)(years)

ASAASA Contralateral Contralateral #NOF#NOF

82.782.7 2.852.85 11.5%11.5%

75.175.1 2.522.52 6.7%6.7%

AO / Muller ClassificationAO / Muller Classification

266266 46.9%46.9%

235235 41.4%41.4%

5757 10.1%10.1%

N = 9N = 9

N = 9N = 9

Evan’s ClassificationEvan’s Classification

73.7%73.7%

N = 418N = 418

26.3%26.3%

N = 149N = 149

ReductionReduction

GoodGood 336336 59.3%59.3%

AcceptableAcceptable 125125 22.0%22.0%

PoorPoor 106106 18.7%18.7%

Cleveland ZoneCleveland Zone

Tip – Apex DistanceTip – Apex Distance

Mean 20mmMean 20mm– RangeRange 5 to 44 5 to 44– SD 6.1SD 6.1

Stable ≈ unstableStable ≈ unstable– 20 vs 22 mm20 vs 22 mm

Tip – Apex DistanceTip – Apex Distance

FailuresFailures

14 revisions - 2.5%14 revisions - 2.5%– In 567 cases!In 567 cases!

10 cut out10 cut out– Superior breach of Superior breach of

femoral headfemoral head

4 failures of plate 4 failures of plate screwsscrews– ““Reverse cut out”Reverse cut out”

Cut Out - TADCut Out - TAD

PP < 0.001 < 0.001

Cut Out - TADCut Out - TAD

Cut OutCut Out

TAD < 25TAD < 25 TAD ≥ 25TAD ≥ 25

YesYes 00 1010

NoNo 437437 120120

TotalTotal 0%0% 7.7%7.7%

Cut OutCut Out

Evan’s UnstableEvan’s Unstable– 10 of 1010 of 10

Displacement > 4mmDisplacement > 4mm– 10 of 1010 of 10

Varus reductionVarus reduction– 8 of 108 of 10

Cut Out – Cleveland ZoneCut Out – Cleveland Zone

Bivariate RegressionBivariate Regression

RankRank VariableVariable P valueP value

11 Tip-Apex DistanceTip-Apex Distance 1.86 x 10 1.86 x 10 -8-8

22 Evan’s UnstableEvan’s Unstable 9.10 x 10 9.10 x 10 -8-8

33 Poor ReductionPoor Reduction 5.25 x 10 5.25 x 10 -7-7

44 Inferior Posterior Hip ScrewInferior Posterior Hip Screw 9.85 x 10 9.85 x 10 -6-6

55 Superior Anterior Hip ScrewSuperior Anterior Hip Screw 3.11 x 10 3.11 x 10 -5-5

Multivariate RegressionMultivariate Regression

RankRank VariableVariable P valueP value

11 Tip-Apex DistanceTip-Apex Distance 1.58 x 10 1.58 x 10 -6-6

22 Evan’s UnstableEvan’s Unstable 4.30 x 10 4.30 x 10 -3-3

33 Poor Reduction Poor Reduction 6.21 x 10 6.21 x 10 -1-1

Failure Rate of 2.5%?Failure Rate of 2.5%?

Choice of implantChoice of implant– Less unstableLess unstable

Quality of resultsQuality of results– Mean TAD 20mm (Baumgaertner 25mm)Mean TAD 20mm (Baumgaertner 25mm)

Computerised PACSComputerised PACS– Statewide tertiary catchmentStatewide tertiary catchment


0

10

20

30

40

50

60

2002 2003 2004

PFN Usage


Choice of implantChoice of implant– Less unstableLess unstable

Quality of resultsQuality of results– Mean TAD 20mm (Baumgaertner 25mm)Mean TAD 20mm (Baumgaertner 25mm)

Computerised PACSComputerised PACS– Statewide tertiary catchmentStatewide tertiary catchment

Study WeaknessesStudy Weaknesses

Level IV evidenceLevel IV evidence

Observer biasObserver bias

Loss of failures to the private sectorLoss of failures to the private sector

? X-rays on clinical need? X-rays on clinical need

SummarySummary

Accurate reflection of experienceAccurate reflection of experience

Captures all complications and revisions in Captures all complications and revisions in Western Australian tertiary centresWestern Australian tertiary centres

AcknowledgementsAcknowledgements

Synthes AustraliaSynthes Australia– Ben FraserBen Fraser

FH, SCGH, RPH Orthopaedic TechniciansFH, SCGH, RPH Orthopaedic Technicians– Particularly Steve and Ken from FremantleParticularly Steve and Ken from Fremantle

My wife May My wife May – Data entry!Data entry!

Insurance StatusInsurance StatusInsuranceInsurance NN %%

HOHO 591591 80.8%80.8%

VAVA 8080 10.9%10.9%

PIPI 3838 5.2%5.2%

MVMV 1414 1.9%1.9%

OVOV 6 6 0.8%0.8%

WCWC 22 0.3%0.3%

Plate LengthPlate Length

LengthLength NN %%

2 hole2 hole 1515 2.6%2.6%

4 hole4 hole 522522 92.1%92.1%

5 hole5 hole 1616 2.8%2.8%

6 hole6 hole 1111 1.9%1.9%

8 hole8 hole 22 0.4%0.4%

12 hole12 hole 11 0.2%0.2%

Plate AnglePlate Angle

AngleAngle NN %%

130 deg130 deg 122122 21.5%21.5%

135 deg135 deg 386386 68.1%68.1%

140 deg140 deg 4646 8.1%8.1%

145 deg145 deg 1010 1.8%1.8%

150 deg150 deg 33 0.5%0.5%

DHS ExtrasDHS Extras

ImplantImplant NN %%

Trochanteric Side PlateTrochanteric Side Plate 1212 2.1%2.1%

Antirotation Screw Antirotation Screw 77 1.2%1.2%

sliding hip screw fixation for proximal femur fractures: an analysis of the predictive factors of...

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