Extraarticular snapping hip: Sonographic findings

MATERIALS AND METHODS. Twenty patients with snapping hip were examined with sonography. Conventional and dynamic sonographic examinations of both hips were OBJECTIVE. The aim of the study was to determine the sonographic findings o f snapping hip and to correlate the findings with the presence or absence o f pain. performed using a 5.0- or 7.0-MHz transducer. RESULTS. Conventional sonographic studies allowed identification of various structural abnormalities (tendinitis, bursitis, synovitis) and helped to d ocument tenderness along the course of specific tendons. Dynamic sonographi c studies revealed 26 cases of snapping hip. In 24 of these 26 cases, the u nderlying cause was clearly identified. Twenty-two snapping hips were cause d by an abnormal movement of the iliopsoas tendon, and two were caused by i liotibial band friction over the greater trochanter. One patient reported a bilateral snapping sensation that could not be documented on sonography. S napping hip was elicited by a wide variety of hip movements. Sonography est ablished an immediate temporal correlation between the jerky tendon motion and the painful snap reported by the patient. Only 14 cases of snapping hip were painful. CONCLUSION. Conventional sonographic studies can identify signs of tendinit is, bursitis, or synovitis. Dynamic sonographic studies revealed the cause of snapping hip in most patients. Snapping hip is characterized on sonograp hy by a sudden abnormal displacement of the snapping structure. In our stud y, a significant proportion of the cases of snapping hip were not painful.