Histological, biochemical, and MRI studies of the growth plate in congenital coxa vara.

Magnetic resonance imaging (MRI) studies in two patients with congenital coxa vara revealed a widened growth plate with expansion of cartilage mediodistally between the capital femoral epiphysis and metaphysis. They did not reveal slippage. Histologic studies showed that the growth plate appeared to be composed merely of irregularly and scarcely distributed germinal cartilage cells with abundant matrix. The histologic studies resembled the histopathologic reports of metaphyseal chondrodysplasia Schmid type, but only with regard to the proximal femoral growth plate. Determination of the sulfur concentration of the cartilaginous matrix was within normal range.