A Brief Follow-Up Report on 228 Medial Rotation Total Knee Replacements at a Mean of 8.5 Years (0 - 19)

Abstract

We present an update in our earlier report on the Medial Rotation Total Knee Arthroplasty (TKA) when a cohort of 228 TKAs in 189 patients (78 M; 111 F) with a mean age of 67.9 years (28 - 90) was reported at a mean follow-up of six years (1 - 13). At that time, the ten-year survivorship for revision for any reason was 94.5% (95% confidence interval (CI): 85.1 - 100), but only 21 knees were at risk at that tenth year. The 10th annual report of the National Joint Registry (NJR) of England, Wales and Northern Ireland reported a deterioration in survivorship of the Medial Rotation TKA beyond the seventh year of follow-up. This implant previously had enjoyed the lowest rate of revision for any reported brand of prosthesis. As a result, we undertook a comprehensive audit of our original cohort at a mean follow-up of 8.5 years (0 - 19). With revision for aseptic loosening, and revision for any reason as the endpoints, with 125 prostheses at risk at ten years, the ten-year survivorship was 96.7% (95% CI: 93.3 - 100) and 92.3% (95% CI: 87.7 - 93.7) respectively. We have confirmed a decline in survivorship at ten years compared to our initial report. We believe that our results probably provide a more accurate picture of the longevity of the implant than figures available from the NJR, as they are based on detailed contemporary enquiries into each patient’s circumstances. Only ten knees in seven patients were lost to follow-up in our review.