PERIPROSTHETIC JOINT INFECTION IN UNICOMPARTMENTAL KNEE ARTHROPLASTY: OUTCOMES FOLLOWING DEBRIDEMENT, ANTIBIOTICS, AND IMPLANT RETENTION

Introduction Periprosthetic joint infection (PJI) after unicompartmental knee arthroplasty (UKA) is a devastating complication with limited data available regarding optimal management. This study aimed to evaluate the efficacy of debridement, antibiotics, and implant retention (DAIR) for PJI following UKA. Methods A retrospective review of patients undergoing DAIR for PJI of a UKA between 2006–2024 at a single large academic referral center was performed. Patients who did not meet the 2018 Musculoskeletal Infection Society (MSIS) criteria for PJI or had <1 year of follow-up were excluded. Treatment failure was defined as failure secondary to infection after DAIR. A total of 26 patients were included in our analysis. Mean follow-up was 4.1 years (range 1.0-13.8 years). Results There were 14 (53.8%) acute post-operative infections and 12 (46.2%) acute hematogenous infections. Methicillin-sensitive S. aureus ( n =8, 30.8%) and methicillin-resistant S. aureus ( n =3, 11.5%) were the most common infecting organisms, with 6 culture negative infections (23.1%). Treatment success was achieved in 18 patients (69.2%). There were no differences in rates of treatment failure between acute post-operative and acute hematogenous infections (35.7% vs. 25%; p =0.6). No risk factors for treatment failure were identified. Of the eight patients that failed treatment, three underwent a repeat DAIR with one success, four were treated with a 2-stage exchange with two successes and one underwent a successful 1-stage exchange, Conclusion DAIR may successfully be used for the treatment of PJI after UKA with successful treatment in approximately 70% of patients.