Definition of Blount's disease:

Blount's disease is a growth disorder of the tibia (shin bone) that causes the lower leg to angle inward, resembling a bowleg.

Causes, incidence, and risk factors:

Blount's disease occurs in young children and adolescents. The cause is unknown but is thought to be due to the effects of weight on the growth plate. The inner part of the tibia, just below the knee, fails to develop normally, causing angulation of the bone.

Unlike bowlegs, which tend to straighten as the child develops, Blount's disease is progressive and the condition worsens. It can cause severe bowing of the legs and can affect one or both legs.

This condition is more common among African-American children. It is also associated with obesity and early walking. There does not appear to be an obvious genetic factor.