Ultrasound and Ultrasound‐Guided Hip Injection Have High Accuracy in the Diagnosis of Femoroacetabular Impingement With Atypical Symptoms
Guanying Gao, Qiang Fu, Ruiqi Wu, Rongge Liu, Ligang Cui, Yan Xu
Abstract
PURPOSE: To evaluate the diagnostic value of ultrasound and ultrasound-guided hip injection in the diagnosis of femoroacetabular impingement (FAI) with atypical symptoms. METHODS: We evaluated consecutive patients diagnosed with FAI and with atypical symptoms who underwent ultrasound-guided hip injection between January 2017 and February 2019. All patients underwent systematic physical examination, ultrasound examination, magnetic resonance imaging (MRI) examination, and ultrasound-guided injection before surgery. Patients with positive response to ultrasound-guided hip injection were recommended to undergo arthroscopic surgery to treat intra-articular pathology. Sensitivity, specificity, accuracy, and positive predictive value (PPV) of ultrasound and MRI were calculated by using arthroscopic surgery as the gold standard. The accuracy of ultrasound-guided hip injection was recorded. Preoperative and postoperative patient-reported outcomes included visual analog scale for pain and modified Harris Hip Score. RESULTS: A total of 78 patients with atypical symptoms were diagnosed with FAI. Among these 78 patients, 50 patients had positive responses to injection and 28 patients had negative responses to injection. A total of 36 patients finally underwent arthroscopic surgery. Response to the ultrasound-guided intra-articular injection was 91.7% accurate for detecting the presence of intra-articular abnormality. There were no complications of injection in any of the patients. The sensitivity, PPV, and accuracy by ultrasound diagnosis of cam impingement were 82.9%, 96.7%, and 80.6%, respectively. The sensitivity and accuracy by ultrasound diagnosis of anterosuperior labral tear were both 72.2%. For MRI diagnosis of cam impingement, the sensitivity, PPV and accuracy were 72.2%, 96.3%, and 74.3%, respectively. For MRI diagnosis of labral tear, the sensitivity and accuracy were both 88.9%. Thirty-four patients (94.4%) surpassed the minimal clinically important difference, and 33 patients (91.7%) achieved the patient acceptable symptomatic state. CONCLUSIONS: Ultrasound and ultrasound-guided hip injection have high accuracy in the diagnosis of femoroacetabular impingement with atypical symptoms. LEVEL OF EVIDENCE: IV, case series.