Eighty patients who had unilateral coxa plana and who had been treated
conservatively were followed to a mean age of sixteen and one-quarter
years, and their cases were reviewed for radiographic evidence of a
disturbance of the femoral capital growth plate. This physeal involvement
was inferred by the presence of one or more of five findings: premature
physeal closure, overgrowth of the greater trochanter, change in physeal
shape, lateral protrusion of the capital nucleus, and medial bowing of the
femoral neck. Premature physeal closure, which was more common in the girls
than in the boys, occurred in 25 per cent of the affected femoral heads,
and 90 per cent of the patients showed some interference with normal
physeal growth in the affected femoral head. A direct correlation was found
between the severity of the physeal involvement and the ultimate deformity
of the femoral head. The possible causes of interference with physeal
growth and damage are discussed.