Idiopathic or primary windswept deformity: the etiological significance of the radiological findings.

The radiographs of 16 knees in eight children who had a valgus deformity of one knee in association with a varus deformity in the other knee were studied. The condition, idiopathic or primary windswept deformity, occurs in 1- to 3-year-old healthy children with normal developmental milestones. The onset of radiological and clinical deformity is abrupt. The disease is a physeal osteochondrosis, and two varieties of it are identical to Blount's tibia vara and to tibia valga, respectively.