Conversion of Fused Knees to Total Knee Arthroplasty: The 21 to 31-Year Clinical Results and Patient Satisfaction.

BACKGROUND There are limited long-term data on the results of conversion of a surgically or spontaneously fused knee to a total knee arthroplasty (TKA) in the literature. The purpose of this study was to determine the long-term (minimum, 21-year) results of TKA in a fused knee. METHODS We reviewed the results of 95 TKAs in the fused knees of 93 patients (mean age, 41.9 ± 9.4 years; range, 23 to 62 years) using a TKA system. The mean follow-up was 25.1 years (range, 21 to 31 years). RESULTS The mean Knee Society score was 88 points (range, 56 to 96 points) at the final follow-up. The mean range of motion was 76.4° (range, 0° to 105°). Nine knees (9%) required revision for aseptic loosening of TKA components. One knee (1%) was revised for pyogenic infection, and another knee was revised for recurrent tuberculous infection. Approximately 80% of patients were satisfied with the TKA. Approximately 67% of patients reported that their quality of life improved greatly after TKA. Kaplan-Meier survivorship, with revision for failure as the end point, was 88.4% (95% confidence interval, 83% to 97%) at 25.1 years postoperatively. CONCLUSIONS Conversion of a fused knee to TKA resulted in good long-term fixation and high satisfaction. LEVEL OF EVIDENCE Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.