Distal locking mechanism influences surgical and radiological outcomes in proximal femoral nailing using distal wedge versus distal screw designs

Abstract

This study aims to evaluate the radiological outcomes of two proximal femoral nails that share similar proximal geometry and sizes, but differ in their distal locking mechanisms. This retrospective study included 244 patients with AO 31-A1/A3 intertrochanteric fractures treated with either Wedge-wing proximal femoral nail (Ww-PFN) (n = 158) or Distally Wedge proximal femoral nail (Dw-PFN) (n = 86). Radiological parameters such as fracture reduction quality, tip-apex distance (TAD), neck-shaft angle (NSA) and time to fracture healing were compared. The Dw-PFN group demonstrated significantly shorter fracture healing time (12.45 +/- 9.7 vs. 15.0 +/- 3.4 months, p < 0.001) and better fracture reduction quality (p < 0.001) compared to the Ww-PFN group. NSA decreased in both groups postoperatively, with a greater mean decrease observed in the Dw-PFN group; this difference was not statistically significant (p = 0.175). However, complication rates were not different. (p = 0.342). The expandable talon mechanism of the Dw-PFN was associated with significantly faster fracture healing and shorter surgical duration compared to the Ww-PFN system. The mean surgical time was 34.1 +/- 6.5 min for the Dw-PFN group and 50.6 +/- 10.4 min for the Ww-PFN group (p = 0.001). These findings suggest that the talon-type distal fixation may be a favorable alternative in clinical practice. Notably, despite the lower rate of good fracture reduction in the Dw-PFN group (28.5% vs. 71.3%), complication and failure rates were comparable, further supporting the safety and clinical feasibility of this locking mechanism.