Osteotomie am distalen Femur zur Korrektur von Genu valgum und Torsionsfehlern

Abstract

Femoral medial closing wedge osteotomy for the correction of valgus malalignment to unload the cartilage in the lateral compartment and/or correction of symptomatic torsional malalignment. Lateral unicompartmental osteoarthritis of the knee with genu valgum in young patients. Symptomatic torsional malalignement of > 30° and < 0°. Grade 3 and 4 cartilage damage in the medial compartment. Heavy smoking. Medial meniscectomy. Extreme obesity. Inadequate soft tissue conditions. The operation begins with arthroscopy of the knee joint. In case of grade 4 lateral cartilage damage, a microfracture is performed. The distal femur is exposed via an anteromedial longitudinal incision starting 10 cm above the patella and ending in the upper third of the patella. The medial femoral cortex is exposed using Hohmann retractors and an oblique closing wedge osteotomy is performed with an oscillating saw. In case of valgus correction, the lateral cortex is left intact. In case of correction of torsional malalignment, the osteotomy plane is horizontal and the lateral cortex is cut. The wedge height is determined preoperatively based on full leg x-rays. The leg axis is controlled intraoperatively with a long metal rod and the use of an image intensifier. The osteotomy is manually closed and stabilized with a locking plate. The patient is mobilized under load with 20 kg body weight for the first 6 postoperative weeks. Full range of motion is permitted. We treated 23 patients with lateral cartilage damage (grades 3 and 4) and genu valgum with medial closing osteotomy of the distal femur (6 men and 17 women). After 3.5-years follow-up, the KOOS increased from 48.4 points to 84.9 points. In one case, there was an early loss of correction, with subsequent revision with bone grafting and lateral osteosynthesis. No peri-or postoperative complications such as infection, thrombosis, and embolism occurred. In 5 cases a torsional osteotomy was performed. The torsional osteotomy was performed 4 times due to chronic patellofemoral instability, and once due to a medial tibiofemoral instability. Healing complications were not observed in this population. Recurrent instability was not observed.