To analyze the causes and the clinical results of treatment for the nonunion of femur shaft fractures that occurred after interlocking intramedullary nail fixation.

We reviewed 19 cases of aseptic nonunion of femur shaft fracture in 174 patients after interlocking IM nailing from March 1999 to February 2004 and followed up for more than one year. First we investigated the factors causing nonunion. For operative options, two methods about exchange nailing and exchange nailing with bone graft were performed. Finally clinical results were analyzed with bone union rate by treatment methods and compared with the nonunion factors statistically.

According to the causes and types of nonunion, we performed larger IM nail change in 10 cases and IM nail change with bone graft in 9 cases. Bone union was achieved in all cases. Average bone union period were 18.5 weeks in exchange group and 16.1 weeks in exchange with bone graft group. There are significant difference between treatment methods statistically (p<0.05). Compared with the nonunion factors, initial open fracture and smoking groups showed late union rate statistically.

Based on our analysis, IM nail change is a useful method for nonunion after initial IM nailing in femoral shaft fracture, and additional bone graft that according to the radiologic pattern and stability, especially the fracture gap is also a useful option for nonunion treatment.