Clinical Results of Fixed-Bearing and Rotating-Platform Total Knee Prostheses

Abstract

Inconsistent results have been reported for posterior-stabilized fixed-bearing and rotating-platform total knee prostheses. The authors sought to determine whether the design changes of these prostheses had led to their achieving their intended objectives at minimum 10-year follow-up. Furthermore, the authors sought to delineate the specific features of these knee prostheses to which good outcomes are attributed. One hundred patients (mean age, 66.2 years) were included in this study. Mean follow-up was 10.4 years (range, 10-11 years). The patients were assessed clinically and radiographically with the Knee Society clinical rating system. In addition, the Western Ontario and McMaster Universities Osteoarthritis Index questionnaire was used and the University of California at Los Angeles activity scores were determined preoperatively and at each follow-up visit. The mean Knee Society knee score was 90 points (range, 70-100 points) in the fixed-bearing group and 92 points (range, 75-100 points) in the rotating-platform group at final follow-up. Mean Western Ontario and McMaster Universities Osteoarthritis Index score was 16 points (range, 5-46 points) in the fixed-bearing group and 16 points (range, 6-49 points) in the rotating-platform group. Mean University of California at Los Angeles activity score was 6.5 points (range, 4-10 points) at final follow-up in both groups. No knee had aseptic loosening of the components, and neither group had osteolysis. The predicted implant survival at 10.4 years was 99% as the endpoint of any reoperation in both groups. The findings of this study suggest that cemented posterior-stabilized fixed-bearing and rotating-platform prostheses have favorable clinical and radiographic results.