A multicenter study was performed to determine which patients have the most potential to benefit from total knee arthroplasty (TKA) with a high-flexion, guided motion design.In 201 consecutive TKAs, the mean gain in range of motion (ROM) was 14 degrees at 3 months and 24 degrees at 6 months. The gain in flexion was significant at 3 and 6 months postoperatively. No differences were found based on preoperative diagnosis, age or sex. There was a poor correlation between body mass index and ROM. Pre- and postoperative flexion also displyed a weak correlation. patients with the least preoperative flexion (< 90 degrees) gained the most degree of flexion (26 degrees). We conclude that the use of a high-flexion, guided-motion TKA allows a significant functional improvement in patients with preoperative stiffness and the preservation of good flexion in patients with normal preoperative flexion.