Open-Wedge Osteotomy Using an Internal Plate Fixator in Patients With Medial-Compartment Gonarthritis and Varus Malalignment: 3-Year Results With Regard to Preoperative Arthroscopic and Radiographic Findings

Purpose: Our purpose was to evaluate the 3-year clinical results of patients with medial-compartment osteoarthritis of the knee and varus malalignment who underwent open-wedge high tibial osteotomy (HTO) with an internal plate fixator (TomoFix; Synthes, Solothurn, Switzerland). Clinical results are correlated with arthroscopic and radiographic findings at the time of surgery. Methods: This study included 69 patients with a minimum follow-up of 36 months who underwent open-wedge HTO for medial-compartment osteoarthritis of the knee. Knee function was assessed before surgery and at 6, 12, 24, and 36 months after HTO by use of subjective International Knee Documentation Committee and Lysholm scores. Arthroscopic findings before HTO and radiographic assessment of the metaphyseal deformity of the proximal tibia (tibial bone varus angle) were correlated with clinical outcome. Results: A significant continuous increase in International Knee Documentation Committee score from 47.25 +/- 18.71 points before surgery to 72.72 +/- 17.15 points at 36 months after HTO was found (P < .001). Grade of cartilage damage of the medial compartment and partial-thickness defects of the lateral compartment did not significantly influence clinical outcome (P > .05 at all time points). The tibial bone varus angle was correlated significantly with greater improvement and better clinical outcome after HTO (P < .01). The overall complication rate of 8.6% was mostly related to surgical causes; nevertheless, a high proportion of patients reported discomfort related to the implant at some point during the follow-up period (40.6%). Conclusions: Open-wedge osteotomy by use of the TomoFix system leads to reliable 3-year results. Results do not depend on the severity of medial cartilage defects, whereas partial-thickness defects of the lateral compartment seem to be well tolerated. The prognostic relevance of patellofemoral cartilage defects remains unclear. Local irritation of the implant was observed in a significant number of patients. Level of Evidence: Level IV, therapeutic case series.