Prediction of femoral head necrosis after Garden type I fracture with CT three-dimensional reconstruction

Abstract Background: Too large posterior tilt after Garden type I femoral neck fracture may lead to femoral head necrosis, but the measurement of posterior tilt is not accurate. Therefore, this study used computed tomography (CT) three-dimensional (3D) reconstruction to measure the relationship between posterior tilt and femoral head necrosis. Methods:A total of 110 patients with Garden type I femoral neck fracture admitted to Tianjin Hospital from 2016 to 2020 were retrospectively analyzed. According to whether femoral head necrosis occurred after operation, they were divided into femoral head necrosis group and non-necrosis group.3D reconstruction was used to measure the posterior tilt of femoral head. The clinical data between the two groups were compared, the risk factors of femoral head necrosis were analyzed by multivariate logistic regression, and the predictive value of posterior tilt on postoperative femoral head necrosis was evaluated by the receiver operating characteristic (ROC) curve. Results: A total of 110 patients were followed up for 18-66 months (mean, 29 months). Necrosis occurred in 12 patients (10.9 %). Multivariate logistic regression analysis showed that BMI≥25kg/m2, reduction quality grade C, and posterior tilt≥20° were risk factors for femoral head necrosis. ROC curve analysis showed that the 3D measured posterior tilt had predictive value for postoperative femoral head necrosis, and the predicted cut-off value was 19.6°. Conclusion: For patients with Garden type I fractures, BMI≥25kg/m2, reduction quality grade C, and posterior tilt≥20° were risk factors for femoral head necrosis after closed reduction and internal fixation. The measurement of posterior tilt by CT 3D reconstruction can better predict the occurrence of femoral head necrosis in patients with Garden type I.