The fake unlocked femoral nail: A configuration to avoid in stable pertrochanteric femur fractures.

Background: Intramedullary unlocked nailing is a safe and used treatment for stable pertrocantheric fractures. Due to the femoral anterior bow of the shaft or a wrong entry point, the distal tip of the nail can be impinging the anterior cortex. This type of situation can compromise the function of the nail, leading to nonunion of the fracture, and cut-out. The aim of this study was to assess the relationship between nail impingement of the anterior cortex of the femur and cut-out and nonunion incidence in patients with pertrochanteric stable fracture treated with an IM nail in an unlocked configuration.

Material And Methods: A retrospective study based on medical records and imaging from the archives of our Level I academic medical center was conducted. The study included patients with proximal femoral fractures treated with short cephalomedullary nails between January 2012 and May 2015. The data collected were analyzed to a possible correlation with the healing time and occurrence of nonunion and cut-out.

Results: The study population counted 429 cases. Applying the inclusion criteria the final series was composed of 169 patients: 112 females (66.73%) and 57 males (33.27%), with a mean age of 81.23 years (range: 67-93 years). Distal tip impingement was observed in 22 cases (13.02%). In total 16 (9.47%) postoperative complications were recorded: 8 non-union and 7 cut-outs. Consolidation was registered in 153 cases and the fracture healing time averaged 14.4 ± 3.8 weeks (range, 11-24 weeks). The cortical impingement was correlated with nonunion and cut-out (p < 0.001) Logistic regression analysis revealed jamming sign significantly affected the fracture healing time (p < 0.001).

Conclusion: The occurrence of cut-out and nonunion after cephalomedullary nailing of stable pertrochanteric fractures appear to be correlated to the presence of the cortical impingement. For this reason, the fake unlocked femoral nail with the cortical impingement is a configuration to avoid in stable pertrochanteric femur fractures.