The aim of this prospective study was to determine which factors are predictive of the post operative range of motion and to evaluate the short-term clinical results after total knee arthroplasty using The Nexgen Legacy Knee LPS-Flex fixed bearing knee system replacement.

A total of 67 patients (101 knees) were enrolled in this study. 101 knees were operated on using the LPS-Flex fixed bearing knee system replacement. The same surgeon performed the surgery between December 2001 and March 2002. The patients' ages ranged from 52 to 77 years, with an average of 68.4 years. Preoperatively the factors considered were the age of the patient, gender, the body mass index, the flexion contracture and further flexion possible. The factors considered postoperatively were patellar tilting and displacement, the postoperative knee and functional score, and a varus deformity. The patients were followed up once every 3 month for up to 2 years.

At the latest follow-up, the average flexion in this series was 130.8° (range, 90°-150°). Thirty knees could attain more than 140° flexion. Twenty patients could comfortably kneel down. The 53 patients could sit cross-legged. The eleven knees could attain less than 120° of flexion at the final follow-up. There was a significant improvement in flexion at each successive review 12 months after surgery. The most important factor that influenced the range of motion after an arthroplasty was the preoperative range of flexion. The average Knee Society knee score was 90 points (range, 80-100), and the function score was 91 points (range, 45-100).

A total knee arthroplasty with LPS-flex showed an excellent range of motion and satisfactory early clinical results. The most important factor that influences the range of motion after an arthroplasty is the preoperative range of flexion.