Expert opinion and controversies in musculoskeletal and sports medicine: femoroacetabular impingement.

Femoroacetabular impingement (FAI) has been proposed as a distinct clinical entity that may be a potentially significant cause of hip osteoarthritis (OA). There is a growing body of literature on this condition, including descriptions of biomechanic mechanisms of impingement, anatomic and radiographic findings, and surgical interventions. Although a connection between anatomic abnormalities of the hip and the development of OA has been recognized for some time, there are limited data on the natural history of FAI and no long-term studies on the effect of surgical treatment. Thus, the diagnosis engenders a degree of controversy in multiple regards, including the diagnostic criteria and the role of operative intervention.