Restoration of Joint Space of the Knee After High Tibial Osteotomy

ABSTRACT

PURPOSE: The purpose of this study was to evaluate whether the medial joint space could be restored by HTO in osteoarthritic knee associated with varus deformity and to evaluate its clinical results. MATERIALS AND METHODS: HTO for medial gonarthrosis was performed in 65 knee joints of 59 patient. The median follow-up period was 36 months. The femoro-tibial angle(FTA) and joint space distance of medial and lateral compartment of the knee was measured on the weight-bearing antero-posterior plain radiogram. And the clinical results were evaluated by HSS knee score composed of pain, function, range of motion, muscle strength, flexion deformity and instability. RESULTS: Medial joint space distance was restored to 2.9 mm in average at postoperative 3 years from 1.8 mm in average preoperatively. Also the lateral joint space distance was maintained without decrease. FTA was corrected from varus 6.3 degree in average preoperatively to valgus 7.3 degree in average at three years postoperatively. HSS score was improved from 69.1 point in average preoperatively to 95 points in average at three years postoperatively. The group of increased joint space distance showed more improved HSS score and more corrected FTA than the unchanged group(p<0.05). When the change of HSS score was compared according to the postoperative FTA, the group, FTA was corrected 7 degree or more had more improved clinical results and more increased joint space distance(p<0.05). Complications were pain or tenderness on the fibular osteotomy site in seven knees, nonunion of fibular osteotomy in seven knee, transient peroneal paresis in four knees and delayed union of tibial osteotomy in one knee. CONCLUSION: At three years follow up after HTO, there was restoration of joint space of the medial compartment of the knee. Also we found the fact that the joint space widening was correlated with clinical improvement. These results suggest that the correction angle of valgus 7 degree or more may have better clinical outcomes.