Prophylactic femoral neck fixation in distal femur fractures: evaluating protection against ipsilateral hip fracture.

PURPOSE: Distal femur fractures occur in older, osteoporotic patients and carry a measurable risk of subsequent ipsilateral hip fracture. Prophylactic femoral neck screw placement is believed by many to mitigate this risk, but clinical evidence is limited. This study evaluates the association between prophylactic femoral neck fixation after distal femur fracture and future ipsilateral hip fracture. METHODS: A retrospective cohort study was conducted at a single Level 1 tertiary trauma center between 2018 and 2024. Adult patients (≥ 18 years) with AO 33A/B/C fractures and Su type 1-3 periprosthetic fractures of the distal femur fracture treated with operative fixation were included. Patients with pathologic fractures, prior hip arthroplasty, or isolated antegrade intramedullary nailing were excluded. Treatment was classified by the presence or absence of ipsilateral prophylactic femoral neck screw fixation. The primary outcome of interest was the incidence of subsequent ipsilateral hip fracture. RESULTS: Of 395 patients, 163 (41%) received prophylactic femoral neck fixation. The prophylactic screw (PS +) cohort included more female patients (81.0% vs. 68.5%, p = 0.006) and more periprosthetic fractures (65.0% vs. 35.8%, p < 0.001). Fixation constructs differed significantly, with nail-plate combinations predominating in the PS + group (69.1% vs 26.4%, p < 0.001). Six patients (1.5%) sustained an ipsilateral hip fracture. No difference was observed in the incidence of ipsilateral hip fracture by prophylactic femoral neck fixation (1.2% vs 1.7%, p = 0.691) or fracture-free survival (p = 0.802). CONCLUSION: Prophylactic femoral neck screw placement was not associated with a reduced rate of ipsilateral hip fracture after distal femur ORIF. Hip fractures occurred in both groups, suggesting that screw placement alone may not be independently protective.