Intramedullary Nailing of Femoral Shaft Fractures: Implications of Interlocking Screw Breakage.

Introduction Femoral shaft fractures are commonly treated with intramedullary nailing (IMN), though complications such as delayed union, nonunion, and hardware failure remain significant challenges. Interlocking screw breakage has unclear implications for fracture healing. Our study examined patients with femoral shaft fractures treated with IMN who developed interlocking screw breakage to evaluate outcomes and complications. Methods The retrospective cohort study included 551 patients with femoral shaft fractures (AO Foundation (AO)/Orthopaedic Trauma Association (OTA) 32A/B/C) treated with IMN at a level one trauma center. Inclusion criteria were acute fractures treated definitively with IMN and a minimum one-year follow-up. Patient demographics, fracture characteristics (including OTA classification), and radiographic union at one year were recorded. Radiographs were reviewed preoperatively, postoperatively, and at clinical follow-up visits. Results Interlocking screw failure occurred in 31 patients (5.6%), of whom 24 had complete one-year follow-up. A total of 185 patients were included in the final analysis (24 with and 161 without screw breakage). There were no significant differences in age (48.5 vs 46.0 years, p = 0.545), BMI (27.8 vs 28.8, p = 0.509), smoking (41.3% vs 40.5%, p = 0.927), or diabetes (p = 0.41). Delayed healing at one year was observed in 66.7% of patients with screw breakage versus 37.9% without (p = 0.013). Among those with screw failure, 36.7% (n=11) had OTA type C fractures, and 41.94% (n=13) required revision surgery for nonunion (n=7), symptomatic hardware (n=4), or infection (n=2). Conclusion Interlocking screw breakage was associated with delayed healing and an increased likelihood of reoperation. Further investigations should focus on risk factor identification for screw breakage for prevention and proper patient counseling.