Imaging of femoroacetabular impingement.

Femoroacetabular impingement is a relatively recently described cause of hip pain that involves degenerative change in the hips of younger patients (less than thirty-five years old) as a result of predisposing pathoanatomy. The two types of impingement, cam and pincer, often occur together and overlap to varying degrees. The diagnostic workup begins with radiography, but magnetic resonance imaging and magnetic resonance arthrography provide more accurate imaging that characterizes not only the pathoanatomy but also other associated findings, including labral tears and cartilage damage.