Chondrolysis and avascular necrosis: complications of slipped capital femoral epiphysis.

Chondrolysis and avascular necrosis (AVN) are serious complications after slipped capital femoral epiphysis (SCFE). Chondrolysis, or acute cartilage necrosis of the capital femoral epiphysis, can occur in treated and untreated SCFE. Its exact etiology has not been conclusively determined, and there may be some connection with hardware penetration into the joint and its development. Because chondrolysis can occur in both treated and untreated hips, an immune mechanism has been postulated. Although some evidence of immune reaction has been confirmed in the joint, no screening test has yet been developed to determine susceptible individuals. AVN is clearly related to impeded blood supply to the femoral head and to severely slipped unstable acute slips. Forceful reduction of the femoral head must be avoided. However, some slips are so unstable that reductions occur merely with positioning of the patient for operation. Improperly placed fixation devices may also play a role in the development of AVN. Chondrolysis and AVN may not be completely avoidable in the treatment of SCFE.