In the name of God

How to deal with Infected Total Knee

Arthroplasty

Mohsen Mardani-KiviAssistant Professor, Orthopedic Department, Guilan University of Medical Sciences

Background

• Total joint replacement is one of the most commonly performed and successful operations in Orthopaedics as defined by clinical outcomes and implant survivorship*

*

Incidence

• Infection has occurred in 1% to 2% of primary TKA surgeries and has been the leading cause of failure following TKA.

• The rate of peri-prosthetic infection has been declining over the last two to three decades, mostly due to operating room environments and operative techniques

Risk Factors for Infected Arthroplasty

• Prior surgery• Surgery time > 2.5 hours• Compromised immune status• Poor nutrition• Diabetes mellitus• Obesity • Smoking

Risk Factors for Infected Arthroplasty

• Chronic renal insufficiency• Diabetes • Neoplasm requiring chemo• Tooth extraction• Skin ulcerations / necrosis• Rheumatoid Arthritis• Recurrent UTI• Oral corticosteroids

Surgical Techniques

HemostasisProlonged operating time

Surgical Techniques

Avoid skin bridges Avoid creation of

skin flaps

Clinical Course

Pain #1SwellingFeverWound breakdown

drainage

Windsor et alWindsor et alJBJSJBJS; 1990; 1990

Work-Up

• Wound History• Physical Exam• Serial Radiographs• Lab/sed rate/CRP (returns

to normal level 3 wk post op.)

• Bone scan / Indium scan• Serum interlukine-6

(100%sensitivity & 95%specifity)

Arthrocentesis

• Gold standard for infection diagnosis:

WBC Cell count more than 2500 cells/mm3 & 60% PMN

Protein high Glucose low

Arthrocentesis

•direct smear•gram strain•Aerobic•Anaerobic•acid fast•fungi

Microbacterial

• Majority of infections : Staphylococci

• Acute hematogenous infections:– Staphylococcus aureus – Beta-hemolytic streptococci – Enterococcus species

• Gram-negative bacilli and anaerobes are also seen in chronic infections but uncommon...

Staphylococcus aureus

Common cause of musculoskeletal infections:

• Early postoperative infection

• Late chronic infection

• Acute hematogenous infection at the site of a prosthetic joint

Staphylococcus aureus

Susceptibility to methicillin treated most effectively with

• Antistaphylococcal penicillin (e.g., nafcillinor oxacillin)

• First-generation cephalosporin.

MRSA: Methicillin-resistant Staphylococcus aureus

• first described in 1961

• Extra penicillin-binding protein (PBP2a) which results in a low affinity for beta-lactam antibiotics such as the penicillins and cephalosporins

MRSA

• poor clinical outcome because of the limited effectiveness of antibiotics.

• Increase cost for treatment.

MRSA

• Increasing trend in MRSA infection

• Staphylococcus aureus (MRSA) from the nosocomial setting and its emergence as a cause of community-acquired infection.

Staphylococcus 64

S. aureus, penicillin sensitive 14 S. aureus, penicillin resistant 28 S. epidermis 22

Gram negative 12 Pseudomonas 7 Escherichia coli 5

Anærobic 6

Other 17

OrganismOrganism PercentPercent

Infection TKR

Treatment of prosthetic infection

• Long-term antibiotic suppression• Surgical débridement with retention of the

prosthesis • Resection arthroplasty• Arthrodesis• One-stage re-implantation procedure• Two-stage re-implantation procedures• Amputation

Treatment of prosthetic infection

• Two-stage reconstruction is the standard practice for treating patients with infected total joint arthroplasty.

• The success rate of two-stage reimplantation has ranged from 80-100%

Treatment Options

– Long-term antibiotic suppression– Surgical débridement with retention of the

prosthesis – Resection arthroplasty– Arthrodesis– One-stage re-implantation procedure– Two-stage re-implantation procedures– Amputation

Antibiotic suppression

Indicated in:– med compromised patients that prosthesis

removal is not feasible– The prosthesis is not loose– Low virulence micro-organism

Duration: life long

Treatment Options

– Long-term antibiotic suppression– Surgical débridement with retention of the

prosthesis – Resection arthroplasty– Arthrodesis– One-stage re-implantation procedure– Two-stage re-implantation procedures– Amputation

Surgical Debridement

• Debridement with antibiotic suppression therapy

– Limited success and Arthroscopic irrigation is not effective

– < 3 weeks

Surgical Debridement

• Debridement with antibiotic suppression therapy

– Strep/staphepi -- best– Avoid repeated attempts– Frozen tissue section– Suction drains– 6 week antibiotic-therapy– Polyethylene exchange

Treatment Options

– Long-term antibiotic suppression– Surgical débridement with retention of the

prosthesis – Resection arthroplasty– Arthrodesis– One-stage re-implantation procedure– Two-stage re-implantation procedures– Amputation

Two-stage Re-implantation

Most successful treatment

•Procedure of choiceProcedure of choice

Two-Stage Re-implantation

Two-Stage Reimplantation

Stage I

remove prosthesis / cement

thorough debridement

Two-Stage Reimplantation

Stage I create antibiotic spacer impregnated with antibioticswound closure

Two-Stage Re-implantation

• Spacer Antibiotic Regimen

• Tobramycin 2.4 gm/3.6 gm per 40 gms of PMMA

• Vancomycin > 0.5 gm to 1 gm per 40 gms of PMMA

Antibiotic Impregnated Spacer

Cidal levels of antibiotic

Spacer to preserve tissue tension

Facilitates re-implant and wound exposure

Local Delivery of Antibiotics

• Antibiotic cemen bead/spacer

• local levels of antibiotics that far exceed those attained with systemic antibiotic therapy.

Local Delivery of Antibiotics

• Antibiotic bead - difficulty in removing after implan

tation.

• Antibiotic impregnated spacers

- minimizes limb-shortening

- limits scar formation

- facilitates reimplantation

Antibiotic for cement spacer

• Microbial Sensitivity

• Bactericidal

• Heat stable

• Powder form

Antibiotic for cement spacer

• Gentamycin

• Tobramycin

• Vancomycin

• Fosfomycin

MRSA

• VancomycinVancomycin is first choice in MRSA

• Vancomycin bead/cement space

• Intravenous vancomycin

Block spacers

1. Simple tibio-femoral block

2. Molded arthrodesis block

3. Articulating mobile spacers (especially in bilateral infected TKAs)

Block spacers

• Simple tibio-femoral block

Block spacers

• Molded arthrodesis block

Block spacers

• Articulating mobile spacers (especially in bilateral infected TKAs)

• Multiple Techniques

Mobile spacer technique

Prosthesis removal

Removal of debris and cement

Cement spacer molding

Insertion with a pack of cement

Final implantation

Postoperative x- ray

PROSTALAC COMPONENTs

PROSTALAC COMPONENTs

• Haffmann’s Procedure:– Using of the patients own prosthesis

Stage II – Antibiotic Treatment Hickman catheter

MIC 1:8 / 6 wks

Patient should use knee brace

In mobile articulating spacers patient is allowed up to 50% PWB and is encouraged ROM

Infections About TKRInfections About TKR

Stage III – Reimplantation

Serial aspirations Pre-op planning Bone scan / Sed rate

• Intra-operative Frozen Section

< 5 PMN’s per HPF – no infection

> 10 PMN’s per HPF – infection

Treatment Options

– Long-term antibiotic suppression– Surgical débridement with retention of the

prosthesis – Resection arthroplasty– Arthrodesis– One-stage re-implantation procedure– Two-stage re-implantation procedures– Amputation

Resection Arthroplasty

Removal all components

Remove all cement

Effective in medically compromised patient

Treatment Options

– Long-term antibiotic suppression– Surgical débridement with retention of the

prosthesis – Resection arthroplasty– Arthrodesis– One-stage re-implantation procedure– Two-stage re-implantation procedures– Amputation

Arthrodesis Indications

Extensor mechanism disruption Resistant bacteria Inadequate bonestock Inadequate soft tissues Young patient

Advantages

DefinitiveDefinitive treatment

Little chance of recurrence

Disadvantages

Difficulty with transfers / small spaces

Increase energy requirements

Algorithm

• TKA

• Clinical Sepsis

(GRAM + (GRAM + Organism) Organism)

< 3 wks< 3 wks > 3 wks> 3 wks

DebridementDebridementAntibiotics (6 wks)Antibiotics (6 wks)

2-Stage2-StageReplantReplant

Infections About TKRInfections About TKR

Algorithm

•DebridementAntibiotics

SuccessSuccess

2-stage 2-stage ReplantReplant

ArthrodesisArthrodesis

Infections About TKRInfections About TKR

No No SuccessSuccess

2-stage Replant2-stage Replant

SuccessSuccessNo No

SuccessSuccess

ResectionResectionArthroplastyArthroplasty

Result of treatment in MRSA infection

• Yogesh Mittal retrospective cohort study

• 37 TKA patients with MRSA or MRSE infection

• Two stage revision: success rate 76% at median duration of follow-up was 51 months (range, twentyfour to 111 months).

MRSA : Antibiotic

Alternate antibiotic

• Allergy to Vancomycin

• Pathogen resistance to Vancomycin

increase reports of decreasing susceptibility of S. aureus to vancomycin

Juan J . Picazo.Activity of daptomycin against staphylococci collected from bloodstream infections in Spanish medical centers.Diagnostic Microbiology and Infectious Disease.2009;64 ,448–451

MRSA sensitivity

Possible alternatives

• Teicoplanin

• Daptomycin

• Leinazolid

• Fosfomycin

Picazo JJ, Betriu C.Activity of daptomycin against staphylococci collected from bloodstream infections in Spanish medical centers.Diagn Microbiol Infect Dis . 2009 ;64(4):448-51.

Schintler MV,High fosfomycin concentrations in bone and peripheral soft tissue in diabetic patients presenting with bacterial foot infection . J Antimicrob Chemother . 2009 Jul 3.

Antibiotic cement in MRSA

Boonsin Buranapanithit : in vitro study

• Gentamycin , Cefalexin bead cannot inhibit MRSA

• Vancomycin , Fosfomycin bead effectively inhibit growth of MRSA

Boonsin Buranapanitkit.In vitro Elution Characteristics of Antibiotic Cement on MRSA organism.The journal of the asean orthopaedic association.2000, 13.33-36

Fosfomycin

• A synthetic broad spectrum antibiotic

• Bactericidal antibiotic

• Heat stable

• High concentration in bone

Boselli E, Allaouchiche B.Diffusion in bone tissue of antibiotics. Presse Med 1999; 28(40): 2265-76

Conclusions

• Prevension

• Adequate surgical debridement

• Staged revision

• Adequate &Susceptibility antibiotic