Predictors of Treatment Failure After 2-Stage Reimplantation for Infected Total Knee Arthroplasty: A 2- to 10-Year Follow-Up

Background: The aim of this study is to identify risk factors which may lead to treatment failure following 2-stage reimplantation for chronic infected total knee arthroplasty (TKA). Methods: We retrospectively reviewed 106 patients (108 knees) who underwent consecutive 2-stage revision for chronic PJI of the knee at our institution between January 2005 and December 2015. A total of 31 risk factors, including patient characteristics, comorbidities, surgical variables, and microbiology data, were collected. Kaplan-Meier survival and Cox regression analyses were used to calculate survival rates and adjusted hazard ratios (HRs) of treatment failure. Results: Within the cohort, 16 of the 108 2-stage reimplantations (14.8%) had treatment failure. The treatment success for 2-stage reimplantation was 91% (95% confidence interval [CI] 0.8-1.0) at 2 years and 84% (95% CI 0.8-0.9) at 5 and 10 years. Multivariate analysis provided the strongest predictors of treatment failure, including body mass index ≥30 kg/m² (adjusted HR 9.3, 95% CI 2.7-31.8, P <.001), operative time >4 hours (adjusted HR 11.3, 95% CI 3.9-33.1, P <.001), gout (adjusted HR 13.8, 95% CI 2.9-66.1, P =.001), and the presence of Enterococcus species during resection arthroplasty (adjusted HR 14.1, 95% CI 2.6-76.3, P =.002). Conclusion: Our study identified 4 potential risk factors that may predict treatment failure following 2-stage revision for chronic knee PJI. This finding may be useful when counseling patients regarding the treatment success and prognosis of 2-stage reimplantation for infected TKA.