Relationship between retention of the posterior cruciate ligament and postoperative flexion in total knee arthroplasty.

This study was conducted to retrospectively analyzed the outcome of 192 total knee arthroplasties in 132 patients with rheumatoid arthritis (118 women, 14 men). The Okayama Mark II prosthesis, which requires the posterior cruciate ligament (PCL) to be resected, was used in 83 knees (group I), the Mark II prosthesis, which allows the PCL to be retained, was used in 68 knees (group II), and the new Okayama PCL-R prosthesis, which also allows the PCL to be retained, was used in 41 (group III). According to the Japanese Orthopaedic Association knee scoring system, the clinical outcome of groups I, II and III at 1 year after the operation were 64.9, 71.2 and 72.3 points, respectively, and the average flexion angles in each group at 1 year were 78.4, 92.6 and 101.3 degrees. Postoperative flexion in groups III was significantly greater than in groups I and II. These results suggest that postoperative flexion is greater when the posterior cruciate ligament is retained.