Success Rates of Debridement, Antibiotics, and Implant Retention in 230 Infected Total Knee Arthroplasties: Implications for Classification of Periprosthetic Joint Infection.

Background: Prosthetic joint infection (PJI) is the most common cause of failure following total knee arthroplasty (TKA). This study aimed to determine the success of debridement, antibiotics, and implant retention (DAIR) in a large cohort of TKA PJIs and assess the utility of current classification systems in predicting DAIR outcomes in early postoperative, late hematogenous, and chronic PJIs.

Methods: In a multicenter review over 15 years, 230 patients underwent DAIR for first episode PJI following primary TKA. Patient demographics, disease and surgical factors, treatment regime, and outcomes were identified. Univariate and multivariate survival analyses were performed to identify factors associated with successful DAIR. Continuous variables with predictive value were further analyzed using receiver operating characteristic curves. The ability to predict DAIR outcomes of multiple classification systems was also assessed.

Results: Patients were followed for an average of 6.9 years. The overall success rate of DAIR was 53.9%. On receiver operating characteristic analysis, 3 months (area under the curve = 0.63) and 1-year age (area under the curve = 0.66) of implant cut-offs was similarly predictive of outcomes. On multivariate survival analysis, DAIR was successful in 64% of "early" PJIs (implant <1 year) vs 38% of "late hematogenous" PJIs (implant >1 year; odds ratio [OR] 1.78, P = .01). For late PJIs (implant >1 year), Staphylococcus aureus (OR 4.70, P < .001) and gram-negative infections (OR 2.56, P = .031) were risk factors for DAIR failure.

Conclusion: DAIR has a high failure rate in all PJIs occurring more than a year post primary TKA, particularly when caused by S aureus or gram-negative bacteria. The age of implant is an important predictor of DAIR outcomes.