The Results of the P.F.C(R) Sigma(TM) RP-F Knee System in High Flex Rotating Platform Total Knee Arthroplasty -Comparison of Preoperative Range of Motion less than 90degrees Versus more than 90degrees-

ABSTRACT

PURPOSE: The purpose of this study was to evaluate the clinical and radiological results of using the P.F.C(R) Sigma(TM) RP-F Knee System for high flex rotating platform-flexion total knee arthroplasty in 2 groups of patients with a preoperative range of motion (ROM) less than 90 degrees or more than 90 degrees, respectively. MATERIALS AND METHODS: From January 2005 to November 2006, eighty-two patients received the P.F.C(R) Sigma(TM) RP-F Knee System for high flex rotating platform total knee arthroplasty, and they were evaluated for a minimum of 3 years. We subdivided the patients into two groups the preoperative ROM less than 90degrees group and the more than 90degrees group. The clinical results were assessed using the ROM, the Hospital for Special Surgery (HSS) score, the Knee Society Score (KSS) and the Western Ontario and MacMaster Universities Osteoarthritis (WOMAC) score. The radiological results were evaluated using the tibio-femoral angle and the presence of loosening or osteolysis of the components. RESULTS: The ROM increased in the two groups at the last follow-up. The mean ROM range at the last follow up was significantly increased more in the less than 90degrees group compared to that in the more than 90o group. The HSS score, KSS, and WOMAC score significantly increased in the two groups, but there was no statistical difference between the two groups. The tibio-femoral angle improved in the two groups. There was no aseptic loosening or osteolysis. CONCLUSION: The postoperative clinical and radiological measures were significantly improved using the P.F.C(R) Sigma(TM) RP-F Knee System on the short term follow-up, and especially for the patients whose preoperative ROM was poor.