Risk factors of neck re-shortening after reduction and fixation in patients with valgus-impacted femoral neck fractures

Background To analyze the risk factors of neck re-shortening after reduction and fixation in patients with valgus-impacted femoral neck fractures. Material and methods Analysis of the clinical data of 46 cases with valgus-impacted femoral neck fractures treated by one surgeon in our hospital from January 2020 and December 2023. The collected clinical data includes: patient's gender, age, body mass index (BMI) and American Society of Anesthesiologists (ASA) classification, fracture side, Cause of injury, time from injury to surgery, Pauwels angle, valgus angle, posterior tilt, Hounsfield units of femoral neck from CT scan, surgical time, internal fixation method, blood loss in operation. SPSS 26.0 software (univariate analysis and Logistic regression analysis) was used to simulate a decision analysis and find risk factors. Results 17 of 46 patients who were included in the study developed neck re-shortening after surgery, with an incidence rate of 37.0%. Univariate analysis showed that there were significant differences in age(P = 0.004), valgus angle(P < 0.001), femoral neck CT HU value(P < 0.001). Logistic regression analysis showed that age > 53.5 years (OR 4.821, 95% CI: 1.248-18.624), initial valgus angle was > 17.6 degrees (OR 2.417, 95% CI: 1.567-3.727), and femoral neck CT HU <= 92.5(OR 15.500, 95% CI: 4.057-59.222) were risk factors of postoperative neck re-shortening(P < 0.05). Conclusion Age, valgus angle, femoral neck CT HU value may be risk factors of neck re-shortening after surgery. For patients with high risk factors, in situ fixation may be a choice, but for young patient with good bone quantity, fixation after reduction is a better choice, which may be beneficial for reconstruction normal hip function.