56 patients with knee osteoarthritis and varus deformity (>10 degrees) were randomized to undergo total knee replacement with either a posterior cruciate-substituting (PS) or cruciate-retaining (CR) prosthesis. The purpose of this study was to the determine the effect of these different devices on postoperative range of motion and knee function when compared over a 7-year follow-up period in patients with a varus deformity. Results demonstrated that patients in the PS group had significantly greater active/passive flexion angles, KSS knee scores at 3 and 12 months, and KSS function scores at 3 months when compared to the CR group. However, patients in the CR group demonstrated significantly shorter time required to perform straight-leg-raising exercises when compared to the PS group.