[Predictors of tibial head transposition in the therapy of varus knee osteoarthritis]

The aim of this study was to find predictors for the clinical outcome in patients who underwent a high tibial osteotomy (HTO).Between 1984 and 1996 a high tibial valgus osteotomy was performed in 155 patients with genu varum. 133 HTO patients were available for follow-up at an average postoperative time of 9.3 +/- 3.0 years. The degree of osteoarthritis was evaluated by radiological (Kellgren) and arthroscopic scoring systems (Outerbridge). Survival time of HTO was estimated using Kaplan-Meier survivorship analysis.The survival rate of HTO was 95 % after 5 years and 77 % after 10 years. In the medial compartment of knee joints with a preoperative Outerbridge stage III/IV or Kellgren stage III/IV the survival rate of HTO was significantly lower when compared to stages 0/I/II (p0.05). Age, sex, tibial malalignment and severity of osteoarthritis in the lateral compartment had no influence on survival rates. The pre-postoperative comparison of radiologically visible signs of osteoarthritis showed mainly either no (46.5 %) or only small (50.5 %) progression. We found that patients who underwent a HTO had good and very good clinical outcomes.We identified severity of preoperative radiological osteoarthritis and intraoperative chondromalacia as predictors of survival rate.