The histological characteristics of congenital coxa vara: a case report of a five year old boy.

In a 51/2 year old boy with unilateral coxa vara who died of unrelated causes histological sections were made of the proximal femora and pelvic growth plates. The proximal femora were also perfused to study the pattern of arterial supply. Evidence of active endochondral ossification was not detectable in growth plates of the affected right femur, the clinically and roentgenographically normal left femur and the pelvis, including a Salter Type II fissure fracture. The endochondral ossification defect found in growth plates of the proximal right femur and pelvis was associated with a reduction in the number and caliber of intraosseous arteries supplying the metaphyseal sides of the growth plates in the proximal femur and those supplying the subchondral region and extraosseous medial ascending cervical arteries on the surface of the femoral neck. This deficiency in endochondral ossification resembles a form of dwarfism associated with a coxa vara and a generalized growth plate disorder.