Background: Reduction and internal fixation by the interlocking intramedullary nail (IMN) are the gold standard in managing femoral shaft fractures with excellent union and a high success rate. although, the reported associated nonunion up to 12.5%.
Objective: To assess the determinants of nonunion fractures shaft femur in adults undergoing IMN treatment.
Patients and methods: This retrospective observational study included 200 adult patients, both sexes, with diaphyseal closed fractures shaft femur previously treated by IMN, who were admitted to the author's institution from April 2018 to April 2022. All patients were subjected to history taking, clinical examination, and radiographic imaging.
Results: The incidence of nonunion of the femoral shaft following IMN was 8%. Body mass index (BMI), diabetes mellitus (DM), non-steroidal anti-inflammatory drugs (NSAIDs), unreamed and delayed weight bearing were significantly higher in the nonunion group than in the union group (P = 0.037. 0.004, 0.002, <0.001 respectively). The type of fracture was significantly different between both groups (P <0.001). Multiple fractures, and nail insertion were insignificantly different between both groups. Reamed was significantly lower in the nonunion group than in the union group (P <0.001).
Conclusion: The incidence of nonunion of the femoral shaft following IMN was 8%. The substantial risk factors leading to nonunion in femoral shaft fractures treated by IMN include higher BMI, the presence of DM, the use of NSAIDs, certain types of fractures, the use of unreamed nails, and delayed initiation of weight bearing.