Accuracy of high tibial osteotomy: comparison between open- and closed-wedge technique.

High tibial osteotomy is an established technique for the treatment of varus malaligned knees. This study analyses the difference between the amount of correction in the preoperative planning and the postoperative result. Furthermore, it compares the difference of the accuracy between open-wedge osteotomy and closed-wedge osteotomy. About 61 patients were either treated with open-wedge or closed-wedge high tibial osteotomy. Preoperative planning and postoperative analysis were performed with a special planning software. The influence of operative technique, aetiology, age, number of previous surgeries, amount of correction and accuracy of the correction compared to the preoperative planning were analysed. The overall postoperative mechanical axis differed form preoperative planning by 2.1° ± 1.7°. The accuracy in the open-wedge group (1.7° ± 1.6°) was significantly higher than in the closed-wedge group (2.6° ± 1.8°; P = 0.038). In patients with congenital varus deformity, the accuracy of the correction was significantly higher than in patients with post-traumatic deformity. The authors recommend open-wedge technique in combination with fixed-angle plates for high tibial osteotomy.