This study sought to perform proximal tibia opening wedge osteotomy on osteoarthritis patients, assess the treatment and identify factors affecting clinical results.

Nineteen patients (19 cases) who had opening wedge osteotomy at our hospital from November 1987 to 1998, and were followed up on for at least 2 years were enrolled in the study. The follow-up period ranged from 2 years to 10 years 4 months averaging 5.3 years. We analyzed those factors that affected the results of operation, such as age, weight, joint space nar-rowing and corrective angle.

Preoperative mean varus angle was 6.8 ° and postoperative mean valgus angle 6.8 °. Mean valgus angle was ° at the final follow-up. Clinical assessment of the patients following the final follow-up showed: excellent in 8 cases, good cases, and fair in 2 cases. In addition, the remaining one case, assessed as poor, received total knee arthroplasty. The postoperative score was 86.3 ±10.6 in the lower age group, and 82.4 ±8.8 in the higher age group (p>0.05). The postoperative knee score was 89.2 5.2 in the non-obesity group, and 78.0 ±11.0 in the obesity group (p<0.1). In relation to Ahlback classification, the postoperative score was 88.3 ±5.0 in the stage I group and 70.0 ±9.9 in stage II group (p<0.05). The postoperative knee scores were 77.3 ±10.8, ±8.0 and 91.0 ±5.3, for those with postoperative valgus angles of below 5 °, 6 to 7 °, and over 8 °, respectively (p<0.05).

We conclude that opening wedge osteotomy with overcorrection of the postoperative valgus angle may be an effective method in osteoarthritic patients with a mild loss of joint space.