Reconstruction of Massive Segmental Distal Femoral Metaphyseal Bone Defects After Open Injury: A Study of 20 Patients Managed with Intercalary Gamma-Irradiated Structural Allografts and Autologous Cancellous Grafts.

Abstract

Our aim was to examine the outcome of gamma-irradiated intercalary structural allografts combined with autologous cancellous grafts in treating large metaphyseal bone defects of the distal femur following open injuries. We prospectively included 20 consecutive patients with large metaphyseal bone defects of >4 cm located in the region of the distal femur following open injuries treated between 2010 and 2018, with a mean follow-up of 2 years (range, 2 to 10 years). Of these patients,18 were men and 2 were women. The mean age was 39 years (range, 22 to 72 years). The mean length of the bone defects was 10.1 cm (range, 5.5 to 14.5 cm), and all were in the metaphysis of the distal femur. The surgical technique included initial early debridement and external fixation followed by reconstruction of the bone defect using structural allograft combined with autologous cancellous bone graft harvested from the iliac crest and locking plate fixation. Definitive fixation was performed at an average period of 22.5 days (range, 3 to 84 days) after injury. Osseous union, rate of infection, complications, need for secondary procedures, and functional outcome using the Lower Extremity Functional Scale (LEFS) at the final follow-up were assessed. After excluding 1 patient who was lost to follow-up, 19 patients with complete follow-up were available for analysis. Of those, 13 patients (68%) achieved complete union at both ends of the allograft with host bone without any further intervention. Three patients (16%) developed aseptic nonunion of the proximal end of the allograft requiring 1 additional procedure each to achieve union. Four patients (21%) developed a deep surgical site infection. Of those, 1 elderly patient required above-the-knee amputation following uncontrolled diabetes and infection. A second patient required 2 additional procedures, and a third patient needed 4 additional procedures to achieve union. The fourth patient developed infection after achieving union, and the infection subsided after debridement and implant removal. The mean LEFS score for all 19 patients was 55 (range, 41 to 75). Use of allograft was a reasonable single-stage alternative solution for massive distal femoral bone defects, which united without additional surgery in two-thirds of the patients and without limb-length discrepancy. Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.