Hip pain in young adults: femoroacetabular impingement.

Femoroacetabular impingement is a more recently noticed cause of hip pain in young patients, and early diagnosis and treatment are critical to prevent development of osteoarthritis and/or delay the need for a more radical treatment option such as arthroplasty surgery. Two general types of femoroacetabular impingement have been described. In the cam impingement, the femoral deformity, usually a bump on the head-and-neck junction, impinges on the acetabular rim. The pincer type of impingement is caused by the deformity on the acetabular side, which may be a deep socket, or an acetabular overcoverage due to retroversion that creates an obstacle for flexion and internal rotation. This article attempts to examine the underlying pathogenesis and discusses diagnostic and treatment modalities.