To compare the performance of a fixed bearing with a PFC Sigma with that of a rotating platform in a total knee arthroplasty performed on patients with a moderate to severe varus deformity.

Among the patients who had received a total knee arthroplasty with either a PFC sigma fixed bearing or a rotating platform between October 1998 to June 2002, 77 cases (53 patients) with a > 15° varus deformity were examined. The surgery time and the clinical ratings and the radiographic images for each patient were investigated.

There were no significant differences in the knee score, functional score, activity level, or radiological findings. There were seven cases where friction sounds were produced from the insertions in the rotating platform whilst walking and there were three cases of lateral instability.

The PFC sigma fixed bearing was more effective for stabilizing the knees with a moderate to severe varus deformity because the rotating platform had a friction sound from the insertions while walking and lateral instability.