Remission rate of implant-related infections following revision surgery after fractures.

PURPOSE: In contrast to a large amount of epidemiological data regarding the incidence of implant infections after fracture management, surprisingly few have been published concerning the success of their treatment. METHODS: This was a single-centre cohort study at Geneva University Hospitals from 2000 to 2012 investigating the remission rates of orthopaedic implant infections after fracture repair and associated variables. RESULTS: A total of 139 episodes were included: There were 51 women (37%) and 28 immunosuppressed (20%) patients with a median age and American Society of Anaesthesiologists (ASA) score of 51 years and 2 points, respectively. The infected implants were plates (n = 75, 54 %), nails (24, 17%), wires (20), screws (10), cerclage cables or wires (3), hip screws (4) or material for spondylodesis (3). A pathogen was identified in 135 (97%) cases, including Staphylococcus aureus (73, 52%), coagulase-negative staphylococci (20), streptococci (7) and 19 Gram-negative rods. All patients underwent antibiotic treatment, and 128 (92%) remained in remission at a median follow-up time of 2.6 years (range one to 13 years). In multivariate logistic regression analysis, the plate infections were significantly associated with lower remission rates [65/75, 87%, odds ratio (OR) 0.1, 95% confidence interval (CI) 0.01-0.90]. No associations were found for gender, age, immune status, ASA score, additional surgical interventions (OR 0.4, 95% CI 0.1-4.1) or duration of antibiotic treatment (OR 1.0, 95% CI 0.98-1.01). CONCLUSIONS: Among all infected and removed orthopaedic implants, plates were associated with slightly lower remission rates, while the overall treatment success exceeded 90%. The duration of antibiotic therapy did not alter the outcome.

Short parenteral antibiotic treatment for adult septic arthritis after successful drainage.

OBJECTIVES: To assess the risk factors for recurrence of septic arthritis with an emphasis on the duration of antibiotic treatment, to gather data for a prospective study on an optimized antibiotic treatment in adults with septic arthritis. METHODS: This was a retrospective single-center study conducted for the period 1996-2008. RESULTS: A total of 169 episodes of septic arthritis in 157 adult patients (median age 63 years; 65 females) were included. In 21 episodes (21/169, 12%), arthritis recurred after the end of antibiotic treatment. Multivariate analysis showed that Gram-negative infection (odds ratio (OR) 5.9, 95% confidence interval (CI) 1.4-25.3), immune suppression (OR 5.3, 95% CI 1.3-22.0), and lack of surgical intervention were associated with recurrence. The size of the infected joint, the number of surgical drainages (OR 1.3, 95% CI 1.0-1.7), arthrotomy vs. arthroscopic drainage (OR 0.5, 95% CI 0.2-1.8), duration of antibiotic therapy (OR 1.0, 95% CI 0.95-1.05), and duration of intravenous antibiotic therapy (OR 1.0, 95% CI 1.0-1.0) were not. Seven days of intravenous therapy had the same success rate as 8-21 days (OR 0.4, 95% CI 0.1-1.7) and >21 days (OR 1.1, 95% CI 0.4-3.1). Fourteen days or less of total antibiotic treatment had the same outcome as 15-28 days (OR 0.4, 95% CI 0.1-2.3) or >28 days (OR 0.4, 95% CI 0.1-1.6). CONCLUSIONS: In this retrospective study of adults with septic arthritis, the duration of antibiotic therapy, or an early switch from intravenous to oral administration, did not statistically influence the risk of recurrence. Due to study limitations, the data cannot be used directly for antibiotic therapy recommendations for septic arthritis. Prospective randomized trials are warranted to optimize the antibiotic treatment of septic arthritis.

Should the methicillin-resistant Staphylococcus aureus carriage status be used as a guide to treatment for skin and soft tissue infections?

OBJECTIVE: Previous skin carriage of methicillin-resistant Staphylococcus aureus (MRSA) leads frequently to empiric antibiotic MRSA coverage for skin & soft tissue infections. METHODS: Retrospective cohort study of orthopaedic patients hospitalized at Geneva University Hospitals (MRSA prevalence; 30%); community-acquired MRSA excluded. RESULTS: A total of 378 skin and soft tissue infections in 346 patients were retrieved. Overall cure was achieved in 330 episodes (87%) after a median antibiotic administration of 15 days. Among all episodes, 102 revealed a positive current MRSA status (during 2 weeks preceding infection; 27%) and 70 (19%) were MRSA carriers in the past. Sensitivity, specificity, positive and negative predictive values of current MRSA skin carriage to predict abscesses due to MRSA were 0.68, 0.77, 0.19, and 0.97, respectively. Fifty-four current MRSA carriers (54/102, 53%) and 30 past carriers (43%) were successfully treated with a non-MRSA antibiotic agent. In multivariate Cox regression analysis, anti-MRSA coverage (hazard ratio 1.2, 95%CI 0.5-2.8) and duration of antibiotic therapy (HR 1.0, 95%CI 0.96-1.02) did not influence treatment failure among patients with positive MRSA carriage. CONCLUSIONS: Current or past HA-MRSA skin carriage poorly predicts the need for anti-MRSA coverage for the antibiotic treatment of skin and soft tissue infections in hospitalized orthopaedic patients.

Duration of post-surgical antibiotic therapy for adult chronic osteomyelitis: a single-centre experience.

PURPOSE: The optimal duration of concomitant antibiotic therapy after surgical intervention for implant-free chronic osteomyelitis is unknown. No randomized data exist. Available recommendations are based on expert's opinion. We evaluated the duration of post-surgical antibiotic treatment related to remission of chronic osteomyelitis. METHODS: This was a retrospective single-centre study at Geneva University Hospitals with a minimal follow-up of two years after treatment. We used multivariate logistic regression analysis with exclusion of pediatric cases and of implant-related chronic osteomyelitis. RESULTS: A total of 49 episodes of implant-free chronic osteomyelitis in 49 adult patients were studied. The median number of surgical interventions was two (range, 1-10). The median duration of post-debridement antibiotic treatment was eight weeks (range, 4-14 weeks). Thirty-nine patients (80%) were in remission after a minimal follow-up of two years. In multivariate logistic regression analysis, one week of intravenous therapy had the same remission as two to three weeks (0.2, 0.1-1.9) or ≥ 3 weeks (0.3, 0.1-2.4). More than six weeks of total antibiotic treatment equalled ≤  six weeks (0.8, 0.1-5.2). CONCLUSIONS: In chronic osteomyelitis in adults, a post-debridement antibiotic therapy beyond six weeks, or an IV treatment longer than one week, did not show enhanced remission incidences. Prospective randomized trials are required to confirm this observation.