Prospective Randomized Comparison of High-Flex and Standard Rotating Platform Total Knee Arthroplasty

We sought to determine if the rotating platform (RP) high-flex design provides improved flexion compared with the standard RP total knee. A total of 142 patients were randomized to receive an RP flex (RP-F) or RP TKA. Supine flexion was measured with a goniometer and lateral x-ray. There was no difference in flexion measured at any interval between groups (1-year clinical flexion RP, 124.0°; RP-F, 124.2°; P = .949; 1-year x-ray flexion RP, 117.9°; RP-F, 117.6°; P = .985). There was no difference between groups comparing the improvement from preoperative to 1-year postoperative flexion (RP-F, 5.2°; RP, 4.1°; P = .580). There were 13 patients with postoperative patellar crepitus, with more in the RP-F group (RP-F, 11 patients [16.7%]; RP, 2 patients [3.2%]; P = .017). Owing to these results, coupled with the increased bone resection and higher cost, we no longer routinely use the RP-F design.