Extract
Femoroacetabular impingement is now recognized as a major risk factor for
the development of osteoarthritis of the
hip1-4.
Repetitive microtrauma at maximal flexion not only causes chronic pain from
the abutment of the femoral head-neck junction with the acetabulum, but it can
also result in structural changes to the hip joint. On the acetabular side,
labral tears, cartilage degeneration, and intraosseous as well as paralabral
extraosseous cysts are often associated with femoroacetabular
impingement1. On the
femoral side, juxta-articular fibrocystic changes—so-called herniation
pits—have been described at the impingement region on the femoral
neck5. In recent
studies, the prevalence of fibrocystic changes at the femoral neck was
reported to range from 5% to 33% in hips with femoroacetabular
impingement6,7;
it should be noted, however, that the fibrocystic lesions in those studies
were relatively small. Progressive enlargement of cysts associated with
femoroacetabular impingement has, to our knowledge, not been reported.