Open reduction and internal fixation of distal femoral nonunions: Long-term functional outcomes following a treatment protocol

Background. Because of the relatively large surface area of metaphyseal cancellous bone, the majority of distal femur fractures heal reliably. Nonunions of the distal femur do rarely occur, however, and the associated bone loss and soft tissue scarring can make successful treatment difficult. Few reports in the literature exist regarding the clinical and functional outcome after treatment of distal femoral nonunions. The purpose of this study was to evaluate the outcome of patients who underwent treatment of a distal femoral nonunion using a standardized treatment plan that included open reduction, internal fixation, supplemental bone graft, lag screw placement, and arthrolysis. Methods. Thirty-one patients with a distal femoral nonunion were Ireated by a single surgeon from 1992 to 2002, and their clinical and radiographic outcomes were assessed. The average age was 57.6 years, and four patients (13%) had sustained open fractures. The average time from injury to diagnosis of the nonunion was 15.9 months and the average time of follow-up was 41.5 months after the definitive nonunion surgery. In all cases a fixed-angle implant was used. Lag screw and bone graft augmentation was used in all patients; 71 % received iliac crest bone graft and 29% received demineralized bone matrix. Outcomes were analyzed using radiographs and the Knee Society Rating Score (KSRS). Results. At final follow-up the union rate was 97%, and the average time to heal was 15.9 weeks. A complete return to preinjury functional status was achieved in 84%. The KSRS Knee Assessment subsection score improved from 43.0 to 78.3 after surgical treatment of the nonunion (p < 0.001). The KSRS Knee Function subsection score also improved from 11.1 to 61.2 at final follow-up (p < 0.001). Conclusions. Distal femoral nonunions may be treated successfully with correction of deformity, stable fixed-angle internal fixation, lag screw placement, and supplemental bone grafting. Knee joint manipulation and arthrolysis are important components of the treatment plan if knee motion is limited because of fibrosis. This yields predictable functional outcome after the surgical intervention.