Case report: Bifid iliopsoas tendon causing refractory internal snapping hip.

BACKGROUND: Treatment of painful internal snapping hip (coxa saltans) via arthroscopic lengthening or release of the iliopsoas tendon is becoming preferred over open techniques because of the benefits of minimal dissection, the ability to address concomitant intraarticular disorders, and a low complication rate. Persistent snapping after release is uncommon, especially when performed arthroscopically. Reported causes include incomplete release, intraarticular disorders, and incorrect diagnosis. Anatomic variants are not discussed in the orthopaedic literature. CASE DESCRIPTION: We report a case of an 18-year-old softball player with internal snapping hip treated with arthroscopic iliopsoas release in the peripheral compartment. Postoperatively, the athlete continued to have painful snapping. Repeat arthroscopy with a larger capsulotomy revealed a bifid iliopsoas tendon causing refractory internal snapping hip, which resolved after revision arthroscopic release. LITERATURE REVIEW: Bifid iliopsoas tendon as a cause of persistent snapping of the hip has not been reported in the orthopaedic literature. Prior sonographic and anatomic studies suggest the bifid iliopsoas tendon exists but is uncommon. PURPOSE AND CLINICAL RELEVANCE: Recognition that a bifid iliopsoas tendon may be the source of painful internal snapping hip is important to prevent clinical failure of surgical management of the internal snapping hip. The differential diagnosis of failed iliopsoas lengthening surgery should include the consideration of an incompletely lengthened tendon attributable to bifid iliopsoas tendon anatomy. Prevention of this complication includes making a large enough capsulotomy to identify the tendon and to ensure it is not bifid.