Long-term outcomes of vascularized fibular grafting for infected non-union of the lower limb: a competing-risk analysis

Background : Infected non-union of the lower limb is among the most challenging conditions in orthopedic surgery. Vascularized fibular grafting (VFG) is a limb-salvage option for large infected bone defects, but outcomes accounting for competing events remain poorly documented. Methods : We conducted a retrospective single-center study of adults treated consecutively with VFG for infected femoral or tibial non-union between 2014 and 2023. Infected non-union combined institutional non-union criteria with fracture-related infection as per international consensus definitions. Treatment success was defined as consolidation with infection remission. Amputation and death were competing events; cumulative incidence of consolidation was estimated using competing-risk methods. Results : A total of 22 patients were included (median age of 45 years). Consolidation was achieved in 17 patients (77 %), infection remission was achieved in 16 (73 %), and treatment success was achieved in 16 (73 %): 9 (41 %) after VFG alone and 7 (32 %) after secondary bone grafting. Six patients (27 %) had unfavorable outcomes: four amputations, one persistent non-union, and one death. The median time to consolidation was 14 months after VFG alone and 38 months after secondary grafting. Cumulative incidence of consolidation reached approximately 18 % at 12 months, 41 % at 24 months, 59 % at 36 months, and 76 % by end of follow-up. All seven patients undergoing secondary grafting for delayed consolidation ultimately achieved union; no formal comparative analysis was performed given the small, time-dependent sample. Conclusion : VFG is a valuable limb-salvage strategy for selected patients with infected non-union. Consolidation may occur late, underscoring the need for prolonged follow-up and competing-risk methodology. Findings should be interpreted given the retrospective design, small sample, and heterogeneous follow-up.