The risk factors of nonunion after intramedullary nailing fixation of femur shaft fracture in middle age patients

Although the optimal treatment for femur shaft fracture is intramedullary nailing fixation, nonunion still occurs. We determined the oligotrophic nonunion rate among femur fractures managed operatively and identified risk factors for reoperation. This was a retrospective clinical study. The data of the patients between 40 and 70 years old with diaphyseal femur fracture who have received reamed and interlocked intramedullary nailing fixation in our hospital from February 2014 to April 2018 were collected. They were followed at regular intervals for at least 1 year after the operation. The primary outcome was nonunion of the fracture site that required reoperation in accordance with the radiographic union scale for tibial shaft fracture (RUST), which is a reasonable score system for lower limb diaphyseal fracture. Three of them were hypertrophic nonunion (1.9%) and the other 13 cases were oligotrophic nonunion (8.6%) at postoperative 12 months follow-up. All of the postoperative plain films showed adequate reduction quality. The three hypertrophic nonunion cases were all obese male with fracture site comminution. Fracture at the proximal third junction, hypertension (HTN) and diabetes mellitus (DM) was significantly associated with oligotrophic nonunion of the fracture site from logistic regression analysis. The mean RUST score 3 months after the operation was not significantly different between the union group and nonunion group but was significantly lower 6 months after the operation in the nonunion group. In conclusion, intramedullary nailing of the femur shaft fractures was associated with a low risk of nonunion at the 1-year follow-up in the middle age group. Those with comorbidity such as obese, HTN, and DM, with fracture site at the proximal third junction or comminution should be followed up closely and rehabilitation with cause aggressively. Radiographic scale as the RUST score at postoperative 6 months could be used to predict this complication.