Late diagnosed congenital dislocation of the hip.

During the years 1975 to 1979, 82,574 children from five counties in southeast Norway were live-born, 197 of whom were treated for late detected CDH, for an incidence of 2.4 per 1,000 live births, i.e., 0.4 promille dislocation, 0.6 promille subluxation, and 1.4 promille dysplasia of the acetabulum without dislocation. All the hips had been found stable at birth. Eighty-six percent were girls, and the left hip was affected in 48 percent, the right hip in 31 perent, and both hips in 21 percent. Only 6.5 percent were delivered in the breech position. This and the stability found neonatally may indicate an etiologic difference between neonatally and late diagnosed CDH.