Three-dimensional evaluation of the femoral medullary canal center for antegrade femoral nailing

Abstract

Objective: Antegrade intramedullary nailing is a commonly used method for the treatment of femoral shaft fractures. However, the optimal anatomical entry point for nail insertion on the proximal femur remains controversial. This study aimed to anatomically determine the projection of the femoral medullary cavity center on the proximal femur using three-dimensional computed tomography imaging. Materials and Methods: Computed tomography scans from 51 adult individuals were retrospectively analyzed. A total of 102 femora (right and left) were reconstructed in 3D and evaluated using the Sectra IDS7 visualization system. The medullary cavity was identified in each femur, and its center was projected onto the superior surface of the proximal femur. The position of the trochanteric fossa and greater trochanter tip was also assessed in relation to the projected center. Results: The center of the medullary cavity was located more anteromedially than the trochanteric fossa by 31.4% on the right and 39.2% on the left. No significant differences were found between genders. The tip of the greater trochanter rarely covered the center. If the trochanteric fossa was used as the entry point, the greater trochanteric tip overlapped with the entry zone in 66.7% (right) and 88.2% (left) of cases. Conclusion: This study demonstrated that the center of the femoral medullary cavity projects anteromedially to the trochanteric fossa. The findings provide key anatomical references for identifying the optimal entry point during antegrade femoral nailing with straight nails. We believe these data may guide surgical planning, reduce complications, and improve surgical success.