[Early damage to the acetabular cartilage in slipped capital femoral epiphysis. Therapeutic consequences]

Epiphyseolysis capitis femoris represents the most common disorder of the adolescent hip, which is followed by a significant rate of early osteoarthrosis. Based on intraoperative findings during the surgical management of 23 hips with epiphyseolysis, early acetabular cartilage abrasion by a cam effect and acetabular rim impingement elicited by the prominent femoral metaphysis have been identified. Both phenomena cause direct damage to the hip joint, especially during flexion and flexion/internal rotation of the hip. As evidenced during surgery, the prominent and sometimes sharp-edged anterior neck metaphysis leveling or exceeding the femoral head showed marks of contusion and the labrum revealed erosions, scars, or tears. Moreover, adjacent acetabular cartilage damage was present ranging from superficial abrasions to a full thickness cartilage loss propagating into the weight-bearing area. In all patients the femoral head cartilage was intact; no avascular necrosis was present. These findings suggest that osteoarthrosis is triggered by direct mechanical damage in the epiphysiolysis hip already during the process of slipping and that chondrolysis appears to represent just the most severe form of this cartilage damage. Consequently, we propose that treatment should not only address the avoidance of a further slippage but also the prevention of impingement and cam leading to early acetabular cartilage damage.