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. Clinical
Relevance: 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.