Analysis on risk factors of re-nonunion after primary revision for femoral shaft nonunion subsequent to failed intramedullary nailing

Objective To analyze the related risk factors of re-nonunion after primary revision for femoral shaft nonunion subsequent to failed intramedullary nailing. Methods A retrospective study was performed in 61 patients with femoral shaft nonunion subsequent to failed intramedullary nailing from June 2008 to June. All patients were divided into re-nonunion group (22 cases) and non-re-nonunion group (39 cases) according to diagnostic criteria of bone re-nonunion. Univariate analysis was used to analyze 14 factors that may lead to the occurrence of re-nonunion after revision for femoral shaft nonunion subsequent to failed intramedullary nailing including age, gender, body mass index (BMI), smoking, alcohol abuse, injury reason, fracture types, intramedullary nail types, locking screws technology for intramedullary nail, bone nonunion sites, bone nonunion time, pathological types of bone nonunion, primary revision methods and autologous bone graft or not, and multi-factor logistic regression analysis was performed on the factors showing a significant difference. Results Univariate analysis showed significant difference in smoking (χ2= 6.564, P= 0.036), BMI (χ2= 6.783, P= 0.021), bone nonunion sites (χ2= 7.316, P= 0.011), primary revision methods (χ2= 8.069, P= 0.003) and autologous bone graft or not (χ2= 6.668, P= 0.027). Logistic regression analysis showed that primary revision methods (OR= 1.027, 95% CI 0.028-0.463, P < 0.05) and autologous bone graft or not (OR= 1.024, 95% CI 0.006- 0.363, P < 0.05) were independent risk factors for re-nonunion after revision of femoral shaft nonunion subsequent to failed intramedullary nailing. Conclusions Primary revision methods and autologous bone graft or not are independent risk factors for re-nonunion after revision of femoral shaft nonunion subsequent to failed intramedullary nailing. By strictly controlling the surgical indications and combining with autogenous bone grafting, it is possible to reduce the occurrence of nonunion after primary revision of the femoral shaft nonunion subsequent to failed intramedullary nailing. Key words: Femur; Fracture fixation, intramedullary; Risk factors