Supracondylar osteotomy of the femur with use of compression. Osteosynthesis with a malleable implant.

BACKGROUND: The goal of treatment of a valgus deformity of the knee that is secondary to osteoarthritis of the lateral compartment is to obtain axial correction of the malalignment of the extremity. Osteosynthesis of the osteotomized femur with use of internal fixation and a stiff implant has not been as successful as expected. We evaluated the accuracy and maintenance of correction and the stability of fixation with a malleable plate after a supracondylar osteotomy of the distal aspect of the femur that was performed to correct a valgus deformity of the knee.

METHODS: We performed an incomplete oblique osteotomy of the distal aspect of the femur in nineteen patients (twenty-one 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 fifty-seven years (range, thirty-nine to seventy-one years), and the mean duration of follow-up was five years (range, two to twelve years).

RESULTS: In seventeen knees, the osteosynthesis withstood the mechanical loading that occurred during the postoperative functional rehabilitation program. Prolonged use of crutches or immobilization, or both, was necessary after the operation in three knees. The osteosynthesis failed in one knee. The loss of correction in eighteen knees, after bone-healing, averaged 1.7 degrees (range, 0 to 4 degrees).

CONCLUSIONS: Our method of achieving osteosynthesis is based on the concept that inherent endogenous stability mechanisms can be mobilized by circumferentially compressing the two cortical tubes with the cut ends congruently apposed to each other. We believe that our technique provides an alternative to osteosynthesis with use of a stiff implant such as a fixed-angle blade-plate device.