Cephalomedullary Nailing for Subtrochanteric and Reverse-Oblique Femoral Fractures: Comparison of a Single Versus Dual Lag Screw Device.

Background: Subtrochanteric proximal femoral fractures are generally treated with cephalomedullary nail fixation. We aimed to compare outcomes of subtrochanteric fracture fixation using a single lag screw (Gamma3 nail, GN) or dual lag screw (INTERTAN nail, IN) device.

Methods: The primary outcome measure was mechanical failure, defined as lag screw cut-out or back-out, nail breakage, or peri-implant fracture. Secondary outcomes included reoperation for mechanical failure, deep infection, or nonunion, and technical predictors of mechanical failure. Adult patients (≥18 years of age) with a subtrochanteric proximal femoral fracture treated at a single center were retrospectively identified using electronic records. All patients who underwent fixation using either a long GN (November 2010 to January 2017) or IN (March 2017 to April 2022) were included. Medical records and radiographs were reviewed to identify operative complications.

Results: A total of 587 patients were included: 336 in the GN group (median age, 82 years; 73% female) and 251 in the IN group (median age, 82 years; 71% female). The risk of mechanical failure was 3-fold higher in the GN group (adjusted hazard ratio [aHR], 2.87; p = 0.010), with screw cut-out (p = 0.04) and back-out (p = 0.04) only observed in the GN group. We observed a greater risk of reoperation for mechanical failure in the GN group, but this did not achieve significance (aHR, 2.02; p = 0.16). Independent predictors of mechanical failure included varus malalignment of >5° for cut-out (aHR, 17.43; p = 0.012), a tip-to-apex distance of >25 mm for back-out (aHR, 9.47; p = 0.019), and shortening of >1 cm for peri-implant fracture (aHR, 5.44; p = 0.001).

Conclusions: For older patients with subtrochanteric and reverse-oblique femoral fractures, the dual lag screw design of the IN nail was associated with a lower risk of mechanical failure compared with the single lag screw design of the GN nail.

Level of evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.