Predictive value of tip apex distance and calcar-referenced tip apex distance for cut-out risk in intertrochanteric femur fractures treated with double lag screw proximal femoral nails

Objective: Cut-out is a major mechanical complication following proximal femoral nailing for intertrochanteric femur fractures. Tip apex distance (TAD) and calcar-referenced TAD (CalTAD) are key radiographic parameters used to predict this complication. This study evaluated the predictive value of TAD and CalTAD in patients treated with double lag screw proximal femoral nails and aimed to identify threshold values specific to this implant design. Methods: This retrospective study included patients with unstable intertrochanteric femur fractures treated using double lag screw proximal femoral nails. Postoperative radiographs were used to measure TAD and CalTAD. Cut-out events were documented during follow up, and threshold values for TAD and CalTAD were determined using ROC curve analysis. Additional parameters such as screw positioning, fracture reduction quality, and bone quality (Singh Index) were also assessed. Results: Both higher TAD and CalTAD values were significantly associated with increased cut-out risk. Cut-off values of 32 mm for TAD and 38 mm for CalTAD were identified. Optimal lag screw positioning (central-central in Cleveland zones), good fracture reduction, and better bone quality were significantly correlated with lower cut-out rates. Conclusion: The TAD and CalTAD are reliable predictors of cut-out risk in intertrochanteric femur fractures treated with double lag screw proximal femoral nails. Their intraoperative evaluation, along with assessment of reduction quality, screw position, and bone status, is essential for minimizing mechanical failure risk. Cite this article as: Akan M, Sezen D, Kart H. Predictive value of tip apex distance and calcar-referenced tip apex distance for cut-out risk in intertrochanteric femur fractures treated with double lag screw proximal femoral nails. Acta Orthop Traumatol Turc., 2026; 60(3), 0515, doi: 10.5152/j.aott.2026.25515.