Abstract
<title>Abstract</title> <p>Purpose: Femoral neck fractures (FNF) in young and middle-aged adults carry a high risk of avascular necrosis (AVN), non-union, and mechanical failure. We evaluated the clinical and radiographic outcomes of Femoral Neck System (FNS) fixation in this population, compared them with published benchmarks, and identified factors associated with failure. Methods: Prospective single-centre cohort of 47 consecutive patients aged 16–60 years with isolated femoral neck fractures treated with FNS (46 analysed; minimum 2-year follow-up), examined as two groups: under 40 years (n = 15) and a middle-aged "borderline" group aged 40–60 years (n = 31). Outcomes (union, AVN, non-union, malunion [shortening > 10 mm]) were benchmarked against published series; associations were assessed with Fisher and rank-based tests and treated as exploratory. Results: Forty-six patients had complete outcome data and were analysed (mean age 43.3 years; 74% male; 41% Singh index ≤ 3; 68% displaced). Union was achieved in 31/46 (67%); at least one complication occurred in 25/46 (54%; some patients had > 1) — non-union 33% (4 implant failures), AVN 15%, malunion 13% — comparable to the published benchmark. AVN was associated with Pauwels type III, subcapital location and comminution; non-union with displacement and borderline reduction; and malunion with older age and lower Singh index. Conclusion: FNS outcomes were comparable to the published baseline for these fractures; angular stability did not overcome the inherent risk of failure. In the older subgroup, malunion and non-union remained frequent, suggesting implant choice alone is insufficient and that anatomical reduction and, in borderline cases, augmentation of fixation warrant consideration.</p>