BackgroundThere have been many studies regarding nongeriatric femoral neck fractures (FNFs), which included patients of a wide age range (between 20 and 60 years old). We aimed to determine whether internal fixation provided acceptable outcomes for middle-aged patients with displaced FNFs, and identify predictors of successful internal fixation.MethodsA total of 117 patients, aged 50–60 years and who underwent closed reduction and unilateral internal fixation using cannulated screws, were included. The outcomes were classified as either “complications” (varus malunion, femoral neck shortening, non-union/early collapse, avascular necrosis, or arthroplasty during the follow-up) or “optimal outcomes” (no complications). Patients with displaced FNFs (Garden stages III–IV, n = 69) were categorized according to whether they experienced acceptable or unacceptable reduction. We evaluated whether patients’ clinical characteristics could predict optimal outcomes.ResultsPatients with displaced FNFs generally experienced complications (84.1%). Twenty-two percent of patients experienced optimal outcomes when acceptable reduction was achieved. Patients with unacceptable reductions experienced complications. Optimal outcomes were positively associated with Pauwels’ type II fracture (OR: 8.67, p = 0.025) and negatively associated with excessive alcohol consumption (p = 0.045).ConclusionsCompared with the younger age group, complication rates are higher in middle-aged patients with displaced FNFs treated using cannulated screws. If internal fixation is to be used for a displaced FNF, patient selection is essential. Care must be taken to avoid selecting patients with excessive alcohol consumption, while successful internal fixation may be more likely for patients with Pauwels’ type II fracture.