Anterior femoroacetabular impingement.

Anterior femoroacetabular impingement is a mechanical hip disorder defined as abnormal contact between the anterior acetabular rim and the proximal femur. The typical patient is a young man who practices a martial art that involves kicking. Mechanical groin pain is the main presenting symptom. Passive flexion and internal rotation of the hip replicates the pain. The range of internal rotation is often limited. Imaging studies show a non-spherical femoral head or overhang of the anterior acetabular rim. Computed arthrotomography or magnetic resonance arthrography visualize focal damage to the anterosuperior labrum and sometimes to the acetabular cartilage. Discontinuing the activity associated with the harmful hip movement is the main treatment. However, arthroplasty and removal of damaged labral tissue may be required. Surgical outcomes correlate negatively with the severity of the cartilage lesions.