Mid-term Results of Total Knee Arthroplasty Using

as possible after surgery. The primary factors that influence postoperative ROM include the diagnosis, preoperative ROM and deformity, age, gender, surgical technique, postoperative pain control and rehabilitation, and lifestyle2,3). Implant design is another important factor for a satisfactory ROM after TKA, and thus, high flexion knee prostheses have been introduced. Compared to the PFC Sigma RP fixed model that allows axial rotation between the polyethylene insert and tibial component, the PFC Sigma RP-F mobile model that has a thicker posterior femoral condyle to minimize polyethylene contact stresses during high flexion incorporates advantages of the mobile-bearing and high flexion models4-6). However, some high-flexion models have been associated with the high incidence of early aseptic loosening that results from the increased shear force between the femur and the femoral component during high flexion7). Cho et al.8) reported that radiolucent lines were observed in 13.8 % of the cases between 3-6 years after high-flexion TKA, 3.2 % of which required reoperation at a mean of 49 months postoperatively. Han et al.7) observed aseptic loosening in 38 % of the patients at a mean of 32 months after high-flexion TKA, and 21 % of which underwent reoperation at a mean of 32 months postoperatively