Osteonecrosis of femoral head in young patients with femoral neck fracture: a retrospective study of 250 patients followed for average of 7.5 years

OBJECTIVE: To investigate the risk factors for osteonecrosis of the femoral head (ONFH) after the treatment of femoral neck fracture in patients under 60 years old. METHODS: A total of 250 cases of femoral neck fracture treated at 3 hospitals in Xuzhou from January 2002 to January 2016 were studied. The patients were followed up for 1~15 years, and the clinical data on femoral head necrosis after the femoral neck operation were analysed retrospectively. Risk factors were recorded, including age, gender, preoperative traction, time from injury to operation, reduction method, type of reduction, BMI, ASA classification, and quality of reduction. Logistic regression analysis was used to evaluate the independent risk factors for ONFH after treatment of femoral neck fracture. RESULTS: The duration of follow-up was 1~15 years, with an average of 7.5 years. None of the 250 patients had fracture non-union, but 40 (16%) had necrosis of the femoral head. The time to necrosis of the femoral head was 1~7 years after the operation, with an average of 3.8 years. Univariate analysis showed that the type of fracture, the quality of reduction, the removal of internal fixation, BMI and ASA classification were risk factors affecting necrosis of the femoral head in patients with femoral neck fracture, and the difference was statistically significant (P < 0.05). Multivariate analysis showed that internal fixation, fracture type (displacement), reduction quality (dissatisfaction), BMI (> 25), and ASA grade (III + IV) were independent risk factors affecting femoral head necrosis in patients with femoral neck fracture. CONCLUSION: A variety of high-risk factors for femoral head necrosis are present after surgery with hollow compression screws for femoral neck fracture in adults. Removal of internal fixation, type of fracture, quality of reduction, BMI, and ASA classification were the most important risk factors influencing the development of femoral head necrosis. During treatment, there should be some targeted measures to reduce the incidence of necrosis of the femoral head.