Incidence and risk factors for fixation failure of femoral neck fractures in adults: a single-center multifactorial analysis

To identify risk factors for fixation failure, avascular necrosis (AVN), and nonunion after reduction and internal fixation of femoral neck fractures in adults. This single-center retrospective study included 217 adult patients who underwent reduction and internal fixation for femoral neck fractures between January 2012 and December 2023. Demographic variables, comorbidities, smoking status, excessive alcohol consumption, mechanism of injury, fracture type, time interval from injury to operation, fixation method, reduction quality, and implant removal were extracted from medical records. Outcomes (fixation failure, AVN, and nonunion) were ascertained during follow-up. Multivariable logistic regression was used to identify factors associated with each outcome. Among 217 patients, fixation failure occurred in 24.0% (n = 52), AVN in 14.3% (n = 31), and nonunion in 9.7% (n = 21). Fixation failure was associated with displaced fracture pattern (Garden III/IV) (OR = 3.314, P = 0.007), poor reduction quality (OR = 2.571, P = 0.036), and excessive alcohol consumption (OR = 3.510, P = 0.010). AVN was associated with excessive alcohol consumption (OR = 5.603, P = 0.002), Garden III/IV fractures (OR = 3.802, P = 0.023), and poor reduction quality (OR = 4.020, P = 0.006). Cannulated screw fixation (OR = 0.255, P = 0.014) and earlier surgery (≤ 1 day: OR = 0.100, P = 0.006; 1–3 days: OR = 0.307, P = 0.028) were associated with lower odds of nonunion. In adult femoral neck fractures treated with internal fixation, fracture displacement, poor reduction quality, and excessive alcohol consumption were independently associated with fixation failure and avascular necrosis. Earlier surgery was associated with reduced odds of nonunion. Cannulated screw fixation was also associated with lower odds of nonunion versus other methods, although residual confounding cannot be excluded. These findings highlight the importance of optimizing reduction quality and addressing modifiable risk factors to improve outcomes. Level III