Intraepiphyseal osteotomy for progressive tibia vara: case report and rationale of management.

Tibia vara (Blount's disease) is characterized by two components, the epiphyseal, which is concerned with articular relationships, and physeal/metaphyseal, which may produce angulation of a long bone. Although the initial etiology is not known, it appears that asymmetrical pressure applied to the angulated proximal tibia results in progressive deformity. In the initial stages, medial and posteromedial pressure causes growth retardation of the epiphysis (articular instability) and the physis (tibia vara). Nonsurgical or surgical treatment that relieves the pressure generally permits reconstitution of normal growth. Continued abnormal pressure and shear forces applied to the physis may result in disorderly enchondral ossification and produce a true osteochondrosis, which may lead to permanent physeal arrest. Osteotomy alone to relieve medial pressure may allow the tibia to grow straight, but residual medial epiphyseal compression and joint instability may persist. A case is reported of a 13 1/2 year follow-up of a patient in whom intraepiphyseal osteotomy restored articular congruity without interfering with longitudinal growth. The risks and experimental nature of this procedure are emphasized.