Femoral neck system: A comparable fixation technique for femoral neck fractures in young adults.

Objective To examine outcomes of femoral neck fractures (FNFs) in non-geriatric adults treated with the Femoral Neck System (FNS; DePuy Synthes, Warsaw, IN) compared to three other fixation techniques.

Methods This was a retrospective study in two Level I Trauma Centers (2019-2024) in adults 18-50 years old with FNFs (AO/OTA 31) that underwent surgical fixation. Patients were classified by fixation method: femoral neck system (FNS), dynamic hip screw (DHS), cephalomedullary nail (CMN) device and cannulated screws (CS). Outcomes compared between groups included: rates of reoperation, union, hardware failure, avascular necrosis (AVN), conversion to total hip arthroplasty (THA), operative time, intraoperative radiation exposure, surgical site infection (SSI) and length of stay (LOS).

Results A total of 95 patients were included (FNS n = 27; DHS n = 15; CMN n = 15; CS n = 38). The majority of the patients were male (64.2 %), with an average age of 32.5 years and follow up time of 363 days. While being used predominantly for displaced fractures (66.7 %, p = 0.001), the FNS had significantly lower rates of hardware failure (74.1 %; p = 0.046), AVN (0 %, p = 0.034) and THA conversion (0 %, p = 0.029). CS had the highest union rates (89.5 %; p = 0.046), lowest reoperation rates (13.2 %; p = 0.030) and were used primarily for non-displaced fractures (63.2 %, p = 0.001). There were no differences among groups in surgical time (p = 0.191), or LOS (p = 0.592). A sub-analysis comparing reoperation rates after closed reduction showed that successful closed reduction was associated with not requiring reoperation (40.5 % vs 14.3 %; p = 0.026).

Conclusion Fixation of FNFs in young adults with the FNS has lower rates of AVN, hardware failure and THA conversion compared to other fixation methods. Fixation with screws has the highest union rate and lowest reoperation rate in this demographic. Fixation of FNFs with the FNS has similar if not better outcomes when compared to other fixation methods. However, surgical factors such as fracture displacement and closed reduction may have influenced outcomes and require further study.

Level of evidence III.