Cam and Pincer Type of Femoroacetabular Impingement

Femoroacetabular impingement (FAI) has gained considerable attention for the past 20 years and has been accepted as a predisposing factor for early osteoarthritis in young patients, particularly in the population participating in sports. Patients with FAI typically present with deep, intermittent groin discomfort during or after activities involving repetitive or persistent hip flexion. Symptomatic improvement can be achieved from arthroscopic debridement of unstable cartilage flaps, shaving of cartilage irregularities, and surgical correction of deformity of the femoral head\endash neck junction. Early and correct diagnosis of FAI has paramount importance for appropriate and timely management of the disorder before the development of osteoarthritis. Magnetic resonance (MR) imaging offers a noninvasive means of assessing the degree of damage to cartilage and adjacent labrum and bone and also evaluating the effectiveness of treatment. This article describes the morphologic types of FAI with emphasis on MR findings.