Comparison of range of motion after posterior cruciate ligament retention or sacrifice with a mobile bearing total knee arthroplasty.

This study evaluated factors affecting range of motion at 24 months in 782 total knee arthroplasties (TKAs) performed between 1983 and 1987 in a nonrandomized, multicenter clinical trial by 17 independent surgeons. A mobile bearing prosthesis was used with either a posterior cruciate ligament (PCL)-retaining or PCL-sacrificing technique. Age and gender did not reveal any differences in outcome. For individual surgeons, the outcome was highly variable and did not reflect the number of cases performed. Postoperative range of motion was greater for the PCL-retaining implant; however, there was also a significant difference in the preoperative motion compared with the PCL-sacrificing device. Postoperative motion improved from preoperative for the whole group. Preoperative motion groups of < 90 degrees gained 28 degrees, 90 degrees to 105 degrees gained 15 degrees, and > 105 degrees lost 1 degree. The change in motion for patients without prior surgery was greater than for those with prior surgery.