Ultrasound Assessment of Hip Subspine Bone Morphology Soft-tissue Correlates with Clinical Diagnosis of Impingement

Purpose: To determine the ultrasound imaging manifestations associated with subspine impingement (SSI), including the osseous and soft-tissue injuries adjacent to anterior inferior iliac spine (AIIS) and to investigate the diagnostic value of ultrasound for SSI. Methods: We retrospectively evaluated patients who attended the sports medicine department of our hospital and underwent arthroscopic treatment for femoroacetabular impingement (FAI) between September 2019 and October 2020, with preoperative hip joint ultrasound and computed tomography (CT) examination within 1 month before surgery. All of the FAI patients were divided into the SSI group and non-SSI group, according to the clinical and intraoperative findings. The preoperative ultrasound and CT findings were assessed. The sensitivity, specificity, and positive predictive value (PPV) of some indicators were calculated and compared. Multivariable logistic regression and receiver operating characteristic curve (ROC) were also used. Results: A total of 71 hips were included, with a mean age of 35.4 +/- 10.4 years, 56.3% were women. Of these, 40 hips had clinically confirmed SSI. The bone morphology type III, heterogeneous hypoecho in anterosuperior joint capsule and the direct head of rectus femoris (dRF) tendon adjacent to AIIS on the Standard Section of the dRF in ultrasound were associated with SSI. Among them, the heterogeneous hypoecho in the anterosuperior joint capsule had the best diagnostic value for the SSI (85.0% sensitivity, 58.1% specificity, AUC = 0.681). The AUC of the ultrasound composite indicators was 0.750. The AUC and PPV of CT low-lying AIIS for the SSI diagnosis was 0.733 and 71.7%, which could be improved when CT was combined with the ultrasound composite indicators with AUC = 0.831 and PPV = 85.7%. Conclusions: Bone morphology abnormalities and soft-tissue injuries adjacent to the AIIS through sonographic evaluation were associated with SSI. Ultrasound could be used as a feasible method to predict SSI. The diagnostic value for SSI could be improved when ultrasound is combined with CT. Level of Evidence: Level IV, case series.