US of the snapping iliopsoas tendon

PURPOSE: To determine the value of ultrasound (US) in the diagnosis of snapping iliopsoas tendon. MATERIALS AND METHODS: In three patients, dynamic US of the hip was performed as the flexed, abducted, and externally rotated hip was extended. The contralateral hip was also evaluated. Hip arthrography was performed in all three patients, magnetic resonance imaging in two, and iliopsoas bursography in two, which was successful in only one case. One patient underwent surgical release of the iliopsoas tendon. RESULTS: At US, an abnormal jerk of the iliopsoas tendon during hip motion was correlated with the painful audible snap. The motion of the contralateral iliopsoas tendon was smooth. No intraarticular abnormality was found in two patients, and an associated labral tear was suspected at arthrography in the third patient. The patient who underwent surgical release of the iliopsoas tendon had great improvement. CONCLUSION: US is a useful dynamic noninvasive technique for the diagnosis of snapping iliopsoas tendon.