Factors Associated With Failure of Synthesis in the Treatment of Proximal Femur Fractures With Cephalomedullary Nails

Introduction: Proximal femur fractures are common in older patients and typically require surgical treatment, with cephalomedullary nails being the gold standard device for this approach. This study aimed to identify the factors associated with the failure of cephalomedullary nailing. Materials and methods: We retrospectively evaluated 380 patients treated with a cephalomedullary nail between August 2021 and August 2022 in a trauma referral center in Brazil. A total of 221 (58.1%) patients were included in the study after applying specific eligibility criteria. Data were collected and rates were determined by reviewing patients' medical records and radiographs. Results: Of 221 patients, 14 (6.3%) had nail failures A significant association was found between post-fixation cervico-diaphyseal angle and the occurrence of nail failure (p<0.001). Furthermore, calcar-referenced tip-apex distance (CalTAD) and tip-apex distance (TAD) values were higher in cases with nail failure than in those without nail failure. Cutoff points were established for TAD and CalTAD to measure the correspondence with nail failures. Conclusion: The present study supports previous evidence that varus reduction potentially causes collapse and nail failure in pertrochanteric fractures treated with cephalomedullary nailing and that high TAD and CalTAD values contribute to the incidence of cut-out.