Femoroacetabular impingement: Evidence of an established hip abnormality
Anderson, S. E., Siebenrock, K. A., Tannast, M. (2010). Femoroacetabular impingement: Evidence of an established hip abnormality. Radiology, 257(1), 8-13. doi:10.1148/radiol.10091480
Femoroacetabular impingement (FAI) syndrome occurs in young, very active individuals, usually in association with high-end sports–related activity or overparticipation in sports-related activity; it manifests as hip pain, restricted motion, positive impingement test results, and appropriate imaging findings; and it can be successfully treated in specific cases without advanced osteoarthritis. Although some of the underlying prearthritic abnormalities (eg, pistol grip deformity, Legg-Calvé-Perthes disease) have been well known for decades, the concept of FAI was not described until the early 1990s. The pathogenetic mechanism of FAI is now well established worldwide, with a history of some 15 years. It is well documented with research from several sites, and midterm surgical results are positive. Two main types of FAI have been described in relation to morphologic variations of the acetabulum and femoral head: pincer type and cam type, respectively. Although one of these types may predominate, patients commonly have a combination of both types.