Bilateral Total Knee Arthroplasty using the Fixed Bearing Platform and the Rotating Platform in the Same Patient

ABSTRACT

PURPOSE: We wanted to evaluate the clinical and radiological results after total knee arthoplasty using the Press Fit Condylar (PFC) Sigma fixed bearing platform knee and the rotating platform knee in the same patient. MATERIALS AND METHODS: We enrolled 44 patients who had undergone bilateral total knee arthroplasties due to osteoarthritis of both knees from November 2001 to December 2004, using the fixed bearing platform and the rotating platform, respectively. The mean age of the study group was 71.5 years (range 65~85 years). The mean follow up period was 74.3 months (range 62~86 months). The clinical results were evaluated according to the knee score, the functional score, the presence of flexion contracture, the range of motion and the complications, and the visual analog scale system was used for the patients' satisfaction. The radiological results using the American Knee Society criteria and the tibiofemoral angle were also evaluated. RESULTS: The average knee score improved from 36.5 to 87.3 in the fixed bearing group and from 38.8 to 87.9 in the rotating platform group, respectively. The average functional score improved from 28.4 to 83.5 in the fixed bearing group and from 32.6 to 85.8 in the rotating platform group, respectively. The average range of knee motion improved from 85.5degrees to 115.5degrees in the fixed bearing group and from 86.6degrees to 116.8degrees in the rotating platform group. The average tibiofemoral angle improved from varus 8.2degrees to valgus 5.5degrees in the fixed bearing group and from varus 7.1degrees to valgus 5.3degrees in the rotating platform group. We did not observe any clinically significant osteolysis or wear. However, there were 3 cases of instability out of the 13 cases in rotating platform group, and this was accompanied by varus deformities of over 15 degree and 6 cases of friction sound during walking. CONCLUSION: We could find no clinical and radiological differences between the fixed bearing platform and the rotating platform in this study. However, we should regard the fixed bearing prosthesis as a good option for the patients with severe varus deformities, with considering performing bulky soft tissue release for obtaining a balanced gap, for preventing spin-out and to correct deformity.