Snapping Hip Syndrome on MRI & X-ray: Imaging Findings

Dynamic ultrasound is the preferred imaging modality for snapping hip because it visualizes tendon movement in real time during provocation maneuvers. For external snapping hip, the transducer is placed over the greater trochanter while the patient performs hip flexion-extension; abrupt anterior displacement of the iliotibial band or posterior gluteus maximus edge across the trochanter is directly visualized. For internal snapping hip, the transducer is placed in the inguinal region during active hip flexion and extension from a position of external rotation; sudden medial-to-lateral displacement of the iliopsoas tendon over the iliopectineal eminence produces the characteristic snap. Associated peritendinous fluid, bursitis, or tendon thickening can be assessed simultaneously. MRI and MR arthrogram are reserved for evaluating intra-articular causes of snapping, including labral tears producing the symptom.

Internal snapping hip, specifically repetitive anterior displacement of the iliopsoas tendon, exerts compressive and shear forces on the anterior acetabular labrum at each snap. Chronic mechanical irritation can produce anterior labral tears, paralabral cysts, and chondral damage at the anterosuperior labrum, particularly in athletes with high-frequency repetitive hip flexion loads. MR arthrogram with radial reformats is used to detect associated labral pathology in patients with internal snapping hip and persistent pain that does not respond to conservative measures. Surgical treatment combining iliopsoas fractional lengthening with arthroscopic labral repair addresses both the mechanical cause and the consequent intra-articular damage.

Initial management prioritizes activity modification to reduce provocative movements, combined with a structured physical therapy program. For external snapping hip, therapy focuses on iliotibial band flexibility, hip abductor strengthening, and lumbopelvic control to reduce compressive loading at the trochanter. For internal snapping hip, progressive iliopsoas stretching and eccentric strengthening through functional range exercises are central. Corticosteroid injection into the iliopsoas bursa or the trochanteric bursa, performed under ultrasound guidance, can reduce inflammation and facilitate rehabilitation. Most patients with snapping hip improve with conservative care over 3 to 6 months; surgery is reserved for those with refractory symptoms or confirmed concomitant intra-articular pathology.