Review Question - QID 3685

The zona orbicularis is the arthroscopic landmark for access to the iliopsoas. Arthroscopic release of the iliopsoas can be performed for treatment of an internal snapping hip, which is usually caused by the iliopsoas snapping over the iliopectineal eminence or the femoral head.

The referenced study by Ito et al performed hip distraction on 7 cadaveric specimens and then sequentially released soft tissue structures to determine which structures were most important for hip stability during distraction. They found that the proximal to middle part of the capsule, which includes the zona orbicularis, had the most influence on hip stability during distraction.

The zona orbicularis is a ring of capsular tissue shown in the MRI in Illustration A and the hip arthoscopy image in Illustration B. Identification of the zona orbicularis can guide the surgeon to the iliopsoas tendon that is immediately deep to this structure. The video clip shows pericapsular release of the iliopsoas tendon. Note that some surgeons choose to release the iliopsoas off the lesser trochanter itself rather than going through the capsule.