Femoral neck exostosis, a manifestation of cam/pincer combined femoroacetabular impingement.

We present 2 cases of cam/pincer combined femoroacetabular impingement treated arthroscopically with labral debridement, acetabuloplasty, and femoral head recontouring. In both cases there was essentially no evidence of osteoarthritis of the hip. However, in both cases raised exostoses were evident on the anterolateral femoral neck in the region that commonly comes into contact with the acetabular rim. On the basis of 3-dimensional dynamic reconstructions, we surmise that these exostoses are a direct result of linear contact between the femoral neck and acetabular rim. We recommend that the presence of these exostoses be carefully noted by the arthroscopic hip surgeon and that they be a geographic marker of the zone of contact between the head-neck junction and the acetabular rim and a guide for the area of head osteochondroplasty in combination with appropriate treatment of the acetabular rim.