Pathogen-driven decision for implant retention in the management of infected total knee prostheses.

PURPOSE: In prosthetic joint infections (PJIs) of the knee, debridement with implant retention is associated with a high risk of recurrence. METHODS: A single-centre cohort study was performed with extensive analysis of the literature covering 1980-2012. RESULTS: In 21 patients (mean age 80.4 years, 19 immunosuppressed), in association with 1.5-three months of antibiotic treatment, an attempt was made to salvage the prosthesis by open (11 patients) or arthroscopic (ten patients) debridement. After a mean follow-up of seven years (range four-20 years), patients were in remission in seven cases (33 %). Remission was achieved in 0 % of all methicillin-resistant Staphylococcus aureus (MRSA) infections (zero/three), in 0 % (zero/three) of methicillin-resistant coagulase-negative staphylococcal infections, in 29 % (two/seven) of methicillin-sensitive S. aureus infections and in 75 % (three/four) of infections due to streptococci. The literature review focused on implant preserving approaches yielded 599 cases with an overall success rate of 47 % (284/599) and significantly more remissions in streptococcal vs staphylococcal knee PJIs (43/54 vs 144/324; p < 0.01, odds ratio 4.9, 95 % confidence interval 2.4-10.9). CONCLUSIONS: In addition to established indications for explantation such as implant loosening, sinus tract or methicillin resistance, the decision for debridement and retention of knee PJIs should also depend on the pathogen. Implant preservation is futile with methicillin-resistant staphylococci, but seems to be a valid option for streptococcal PJIs.

Six weeks of antibiotic treatment is sufficient following surgery for septic arthroplasty.

OBJECTIVES: In the treatment of prosthetic joint infections (PJI), the benefit of antibiotic therapy for more than 6 weeks after surgery is uncertain. We compared PJI cure rates according to the duration of antibiotics, 6 versus 12 weeks. METHODS: A prospective observational non-randomized study in Geneva University Hospitals 1996-2007. RESULTS: A total of 144 PJI (62 hip arthroplasties, 62 knee arthroplasties, and 20 hip hemiarthroplasties) were included with a prolonged follow-up ranging from 26 to 65 months. Surgical treatment included 60 débridements with implant retention, 10 one-stage exchanges of the prosthesis, 57 two-stage exchanges, and 17 Girdlestone procedures or knee arthrodeses. Seventy episodes (49%) received 6 weeks antibiotic therapy and 74 episodes, 12 weeks. Cure was achieved in 115 episodes (80%). Cure rate did not change according to the duration of intravenous antibiotics (>8 days, 8-21 days, >21 days) (Kruskal-Wallis-test; p = 0.37). In multivariate analysis, none of the following parameters was statistically significantly associated with cure: two-stage exchange (odds ratio 1.1,95%CI 0.2-4.8); number of débridements (0.9, 0.4-1.9); six weeks antibiotherapy (2.7, 0.96-8.3); duration of intravenous course (1.0, 0.96-1.03); sinus tract (0.6, 0.2-1.7); or MRSA infection (0.5, 0.2-1.5), although implant retention showed a tendency for less cure (0.3, 0.1-1.1). CONCLUSIONS: Following surgery for treatment of PJI, antibiotic therapy appears able to be limited to a 6-week course, with one week of intravenous administration. This approach needs confirmation in randomized trials.