390. Treatment and Outcome of Methicillin-Resistant Staphylococcus aureus Hip and Knee Prosthetic Joint Infection

Background Methicillin-resistant Staphylococcus aureus (MRSA) total hip and knee prosthetic joint infections (PJI) can be highly morbid and difficult to treat. Other clinical factors notwithstanding, explantation is usually recommended, although comparative treatment data are lacking. We sought to compare the success of implant retention to two-stage exchange in MRSA-infected PJI to better understand treatment options in this difficult cohort. Methods A retrospective cohort of hip and knee PJIs from 2009 to 2016 were identified by ICD code and surgical treatment. All cases met MSIS criteria for PJI, and had culture-confirmed MRSA from synovial or intra-articular tissue culture. PJIs were either treated with exchange arthroplasty or debridement with antibiotic and implant retention (DAIR). Success was defined as no further surgical treatment for infection at two years. Kaplan–Meier estimates were used to calculate the 2-year survival rate free from treatment failure. Univariate logistic regression was performed to identify risk factors associated with treatment failure. Results 65 MRSA PJIs were identified with 42 undergoing explantation and 23 undergoing DAIR. Demographics, Charlson comorbidities, infection type (early post-operative, hematogenous or late chronic), and history of prior PJI were not significantly different between treatment groups. Survivorship at two years was 75% (95% confidence interval [CI] 61–88%) for exchange compared with 29% (95% CI 10–48%) for DAIR, P = 0.0002. Within the exchange group, knee PJIs were more likely to fail than hip PJI (odds ratio [OR] 7.1, CI 1.3–38, P = 0.02), and patients with diabetes were more likely to fail (OR 17, CI 1.6–178, P = 0.02). Conclusion MRSA PJIs treated with DAIR have worse outcomes than those treated with prosthesis exchange. Further investigation is needed to identify predictors of DAIR success, to optimize surgical treatment choice, and to improve outcomes of these difficult infections. Disclosures All authors: No reported disclosures.