Snapping hip is an uncommon cause of lateral hip pain, not a single syndrome, but a group of disorders that have in common abnormal passage of musculotendinous units or fascial bands over the greater trochanter. In an effort to better understand the pathophysiology responsible for snapping hip syndrome in a specific patient, it is helpful to classify the pathology as to the anatomic structures or region responsible for the symptomatology (Table 134.1). To this end, snapping hip syndrome can be classified as external, internal, or intra-articular. The pathophysiology associated with external slipping hip syndrome is related to abnormal passage of the posterior border of the iliotibial band or the anterior border of the gluteus maximus muscle over the greater trochanter (Fig. 134.1). The pathophysiology of internal snapping hip syndrome is thought to be related to the abnormal passage of the iliopsoas tendon over the iliopectineal eminence (Fig. 134.2). Loose bodies, synovial abnormalities, and tears of the labrum have been implicated as the cause of intra-articular snapping hip syndrome.

The constellation of symptoms associated with external snapping hip syndrome includes a snapping, clicking, or grating sensation in the lateral hip associated with sudden, sharp pain in the area of the greater trochanter. The symptomatology of snapping hip syndrome occurs most commonly when the patient rises from a sitting to a standing position or when walking briskly. Often, trochanteric bursitis coexists with snapping hip syndrome, further increasing the patient’s pain and disability.

Patients suffering from external snapping hip syndrome can usually recreate the snapping and pain by moving from a sitting to a standing position and by adducting the hip. These patients will also usually exhibit a positive snap test. The snap test is performed by having the patient move rapidly from a squatting to a standing position while the clinician palpates the area over the grater trochanter (Fig. 134.3). The diagnosis of external snapping hip syndrome can be strengthened by performing the external snapping hip test (Fig. 134.4). Point tenderness over the trochanteric bursa indicative of trochanteric bursitis also is often present.

Plain radiographs are indicated in all patients who present with pain thought to be emanating from the hip to rule out occult bony pathology and tumor. Based on the patient’s clinical presentation, additional testing may be indicated, including complete blood cell count, prostate-specific antigen, sedimentation rate, and antinuclear antibody testing. Magnetic resonance and/or ultrasound imaging of the affected hip is indicated to help confirm the diagnosis and identify coexistent trochanteric bursitis, as well as to rule other hip pathology (Fig. 134.5).

The trochanteric bursa lies between the greater trochanter and the tendon of the gluteus medius and the iliotibial tract (Fig. 134.6). The gluteus medius muscle has its origin from the outer surface of the ilium, and its fibers pass downward and laterally to attach on the lateral surface of the greater trochanter. The gluteus medius locks the pelvis in place when walking and running. The gluteus medius muscle is innervated by the


superior gluteal nerve. The iliopectineal eminence is the point at which the ilium and the pubis bone merge (see Fig. 134.2). The psoas and iliacus muscles join at the lateral side of the psoas, and the combined fibers are referred to as the iliopsoas muscle. Like the psoas muscle, the iliacus flexes the thigh on the trunk or, if the thigh is fixed, flexes the trunk on the thigh, as when moving from a supine to sitting position. The iliotibial band is an extension of the fascia lata, which inserts at the lateral condyle of the tibia (see Fig. 125.6). The iliotibial band can rub backward and forward over the lateral epicondyle of the femur and irritate the iliotibial bursa beneath it (Fig. 134.7).