Long-Term Outcomes and Risk Factors for Treatment Failure After Internal Fixation of Femoral Neck Fractures: A 5-Year Follow-Up Study

Objectives: We sought to characterize long-term outcomes following internal fixation of femoral neck fractures (FNFs) in a consecutive cohort and to examine factors related to treatment failure. Methods: The study comprised 427 consecutive patients treated with internal fixation for FNFs at Beijing Jishuitan Hospital during 2017. Long-term outcomes were assessed through medical-record review, available routine imaging, and telephone follow-up during the fifth postoperative year. The primary long-term outcomes were osteonecrosis of the femoral head (ONFH) and major reoperation. Risk factor analysis was performed in 234 patients with radiographic follow-up of ≥6 months, in whom treatment failure was defined as a composite of ONFH, major reoperation, malunion, nonunion, and/or fixation failure. Associations between candidate factors and treatment failure were examined using univariable and multivariable logistic regression. Results: Long-term outcome status was successfully ascertained in 373 of 427 patients (87.4%), corresponding to a loss-to-follow-up rate of 12.6%. Overall, 98 patients (26.3%) developed ONFH and 57 (15.3%) underwent major reoperation, all of which were hip arthroplasties. Among the 234 patients with radiographic follow-up, 111 (47.4%) experienced treatment failure. In the multivariable analysis, high-energy injury (adjusted odds ratio [aOR] 2.90, 95% CI 1.06–7.92), displaced fracture (aOR 12.03, 95% CI 4.33–33.40), subcapital fracture location (aOR 2.14, 95% CI 1.04–4.41), and fair-to-poor reduction quality (aOR 3.95, 95% CI 1.88–8.31) were independently associated with treatment failure. In exploratory age-stratified analyses, fracture displacement and fair-to-poor reduction quality remained consistently associated with treatment failure in both age groups. Conclusions: This consecutive real-world cohort achieved long-term outcome ascertainment in 87.4% of the original population. Long-term complications after internal fixation of FNFs remained substantial. Fracture displacement and fair-to-poor reduction quality were the most consistent factors associated with treatment failure across the primary and exploratory age-stratified analyses, emphasizing the importance of careful treatment selection and adequate fracture reduction.