A histochemical study of slipped capital femoral epiphysis

Core biopsies of the proximal femoral growth plate from three patients with slipped capital femoral epiphysis were compared with three normal growth plates from patients of similar ages. The growth plates of patients with slipped capital femoral epiphysis had a normal resting zone, a loose and fibrillated proliferative zone, and a very disarranged and thickened hypertrophic zone. The proliferative zone stained strongly with alcian blue, suggesting the presence of abundant proteoglycans in the cartilage matrix. The thickened hypertrophic zone was strongly positive to periodic acid-Schiff stain, indicating the presence of abundant structural glycoproteins. Enchondral ossification was scanty and irregular, and there were large clusters of cartilage in the metaphysis. Slippage occurred through the thickened proliferative and hypertrophic zones.

The proximal femoral growth plate in slipped capital femoral epiphysis is histochemically abnormal and histologically disarranged. These features contribute to abnormal widening of the growth plate and to further slippage.