Femoroacetabular impingement

The two major categories of conditions that give rise to osteoarthritis (OA) of the hip are dysplasia and nondysplasia. Dysplasia, commonly with anterolateral deficiency, may account for up to 40% of OA cases in the United States and over 80% of OA cases in Japan and Italy. In a distinct category of patients, there is no identifiable cause for OA, or so-called idiopathic arthritis. There is emerging evidence that subtle morphologic abnormalities around the hip, resulting in femoroacetabular impingement, may be a contributing factor in many instances.