[Incomplete, supracondylar femur osteotomy. A minimally invasive compression osteosynthesis with soft implant]

The aim of treatment of a valgus deformity and osteoarthrosis of the lateral compartment of the knee is to obtain axial correction of the misalignment of the extremity. Osteosynthesis of the osteotomized femur using internal fixation and a stiff implant has not been as successful as expected. We evaluated the accuracy of correction and the stability of fixation with a malleable plate after supracondylar osteotomy of the distal aspect of the femur that was performed to correct a valgus deformity of the knee. We performed an incomplete oblique closing-wedge osteotomy of the distal aspect of the femur in 32 consecutive patients (34 knees) and stabilized the osteotomy site with a malleable, semitubular plate, which was bent to form an angled plate, and lag screws. Postoperatively, the patients were immediately encouraged to walk, with partial weight bearing on the affected extremity. The mean age of the patients was 52 years, and the mean follow-up period was 4.4 years. In 32 knees, the osteosynthesis withstood the mechanical loading that occurred during the functional rehabilitation program. Due to pain or incorrect weight bearing, splinting was necessary to maintain the integrity of the osteosynthesis in three knees. The osteosynthesis failed in two knees. The mean deviation of the achieved tibiofemoral axis in the healed bone from the intended tibiofemoral axis was less than 2 degrees, and the maximal deviation less than 5 degrees. The Insall score was 21 points higher 4.4 years postoperatively than it had been preoperatively. Our method allows reliable correction of the tibiofemoral axis using intrinsic stability mechanisms to compress the congruently aligned cut ends of the cortical tubes. We believe that our technique provides an alternative to osteosynthesis using of a stiff implant such as a fixed-angle blade-plate device.