The course of treatment in nonunions of long bones: can we predict when exchange nailing may fail?

Abstract

Exchange nailing is often used to treat femoral and tibial nonunions. Its success rate varies with reports of 50-100% success. We sought to determine the trajectory of healing and identify factors associated with the failure of exchange nailing in the treatment of nonunion. This was a retrospective chart review at two level I trauma centers. Patients with aseptic femoral and tibial nonunions treated with exchange nailing were included. The primary outcome was union prior to or at 1 year following treatment. Treatment failure was defined as lack of union (defined as lack of bridging bone on 3 or more cortices) at 1 year or an additional procedure to promote union. 138 patients with aseptic nonunion of tibia or femur fractures initially treated with intramedullary nailing were identified. 77% of patients went on to successful union within 1 year after exchange nailing. The overall union rate was 9.6% at 6 weeks, 36.2% at 3 months, and 67% at 6 months. In femurs, less than 100% cortical contact, diabetes mellitus, and use of bone graft was associated with failure of exchange nailing. On multivariate analysis, only less than 100% cortical contact was associated with an increased risk of failure. No predictors were identified in the tibia. Rates of union were comparable between nonunion at diaphyseal and non-diaphyseal fracture sites, regardless of morphological type. Exchange nailing is a valuable treatment option and may be considered for aseptic nonunions of long bones. Surgeons should consider avoiding this technique when treating femoral nonunions which have less than 100% cortical contact.