The aims of this study were to assess the clinical outcomes especially range of motion of the knee after total knee arthroplasty with sigma RP-F versus LCS RP.

110 knees underwent total knee arthroplasty with LCS, and 59 knees with PFC sigma RP-F. We performed a prospective clinical trial. At the time of the one-year follow-up, we compared the clinical outcomes of two groups. In LCS group, LCS AP glide type group was excluded. Range of motion, the knee score, functional score and HSS score etc. were assessed.

91 knees were available. The mean active non-weight-bearing range of motion at one year was 124 (95% confidence interval) in the fifty-six knees that underwent a LCS and 127 (95% confidence interval) in the thirty-six knees that underwent a PFC sigma RP-F (p=0.55). There were no significant differences in the knee score (the mean 94.12 in LCS, 93.54 in RP-F, p=050), functional score(the mean 62.58 in LCS, 65.14 in RP-F, p=0.91) and HSS score (the mean 87.73 in LCS, 87.85 in RP-F, p=0.50).

Although PFC sigma RP-F has the design that is advantageous in knee flexion, we found no significant differences between the groups with regard to range of motion or clinical outcomes.