History: 60 yo male with left hip pain
Solution: Femoroacetabular impingement syndrome is a significant cause of early osteoarthritis in the hip. Two types of impingement are identified: Pincer impingement is characterized by focal or general overcoverage of the femoral head by the acetabulum and cam impingement is due to an aspherical portion of the femoral headâ€“neck junction, as is seen in this case. Most patients have a combination of the two. An excellent article on the subject was published in AJR in 2007 (AJR 2007; 188:1540-1552). Please see this for additional detail.