Arthroscopic Iliopsoas Release for Coxa Saltans Interna (Snapping Hip Syndrome)

Abstract

Coxa saltans interna is a hip syndrome resulting in the iliopsoas tendon snapping pathologically over structures beneath it, causing a loud audible click or clunk, which may be associated with pain. It is thought the most common involved structure it courses over is the iliopectineal eminence (Figure 12.1); however, other intraarticular structures may be large loose bodies and exostoses. The differential diagnosis must rule out labral tears, synovial chondromatosis, and abnormal shapes of the femoral head from an old slipped capital femoral epiphysis or hip dysplasia and acetabular retroversion. The iliacus and the psoas fuse to become one musculotendinous unit as they pass in a sulcus between the anteroinferior iliac spine and the iliopectineal eminence (Figure 12.2). The tendon courses over the anterior hip capsule as it passes posteriorly in the iliopsoas bursa to insert onto the lesser trochanter (Figure 12.3). The tendon assumes a lateral position on the iliopectineal eminence when the hip is in flexion, abduction, and external rotation. As the hip is moved into extension, adduction, and internal rotation, the tendon moves from lateral to medial; however, the musculotendinous portion remains in the groove.1 The symptomatic snapping hip is caused by the back-and-forth movement over the anterior hip capsule and femoral head. The etiology may be a hyperextension injury to the hip capsule or tendon itself. Other causes may be from exostoses on the acetabular rim or femoral head as well as the lesser trochanter.2 The iliopsoas bursa may also become inflamed or hypertrophic, leading to the condition. Of note, the iliopsoas bursa is the largest bursa in the body, measuring 7 cm long and 4 cm in width.