Why Do Revision Total Knee Arthroplasties Fail? A Single-Center Review of 1632 Revision Total Knees Comparing Historic and Modern Cohorts.

ABSTRACT

BACKGROUND: Utilization of revision total knee arthroplasty (TKA) has been increasing, and reasons for failure are less understood than those of primary TKA. The purpose of this study is to identify the rates and mechanisms of failure of revision TKA, and compare those between a historic (1986-2005) and modern (2006-2015) cohort. METHODS: All revision TKAs performed at a single institution between 1986 and 2015 were reviewed, with minimum 2-year follow-up. Failure was defined as a second revision surgery in which any component was exchanged. Diagnosis at the time of index and any re-revision procedure was determined. RESULTS: In total, 1632 revision TKAs in 1560 patients were reviewed. The average age was 65.1 and the average follow-up was 61.4 months. Overall failure rate was 22.8%, with no significant differences between the historic and modern cohort (25.1% vs 22.0%, P = .19). The leading cause for failure was infection in 38.5% of failures. The next most common causes for failure were aseptic loosening (20.9%) and instability (14.2%). Failure rate among revision TKAs for infection was 33%, with 67.2% failing due to repeat infection. Multivariate analysis found that septic index revision (odds ratio [OR] 1.91, 95% confidence interval [CI] 1.47-2.48), male gender (OR 1.41, 95% CI 1.11-1.78), and age less than 65 (OR 1.56, 95% CI 1.23-1.97) were independent risk factors for failure. CONCLUSION: There remains a high rate of failure in revision TKA, with infection being the most common reason for failure. Rates and primary reasons for failure have not changed significantly in the past decade.