Which side should be taken care of when positioning a lag screw in intertrochanteric femoral fracture: right or left?

Purpose: We aimed to demonstrate which side should be taken care of when fixating an intramedullary nail with a lag screw for an intertrochanteric fracture under the influence of clockwise torque.

Methods: From 2021 to 2023, 63 patients who underwent surgery for intertrochanteric fractures were divided into two groups: Group A (45 patients with left-side fractures) and Group B (18 patients with right-side fractures). We evaluated intraoperative images before fixation and postoperative radiographs to assess anteromedial cortical support. Clinically, the time to union and union rate were evaluated, and the complications, reoperation, and Koval score at one year were reviewed.

Results: Pre-fixation reduction quality showed no significant difference between groups. However, in terms of postoperative reduction quality on the lateral view, Group A had the highest incidence of neutral anterior cortical support (ACS) (62%), whereas Group B had the highest incidence of negative ACS (78%) (p < 0.001). Bone union occurred in 98% of Group A cases and 78% of Group B cases (p = 0.021). The mean time to union was shorter in Group A (5.2 months) compared to Group B (5.8 months) (p = 0.004). The mean Koval score was also better in Group A (2.4 vs. 2.0, p = 0.031).

Conclusion: When fixating intertrochanteric fractures with an intramedullary nail using a lag screw, right-sided fractures tended to exhibit negative ACS on lateral radiographs by clockwise torque. Therefore, particular attention should be paid to maintaining proper reduction while fixating right-sided intertrochanteric fractures.