Femoroacetabular impingement: current concepts and controversies.

The concept of femoroacetabular impingement (FAI) emerged following the observation that FAI can be precipitated by acetabular reorientation and can produce new labral damage. Interest in the association between chondrolabral damage and variations in femoral and acetabular anatomy has established a causal relationship between mechanical aberration in the function of the hip joint and the development of labral and cartilage damage. The accepted definition of FAI is that it is characterized by abnormal mechanical contact between the rim of the acetabulum and the upper femur. Combinations of certain morphologies and movements may lead to FAI.