Development of late congenital hip dysplasia: significance of ultrasound screening.

Ultrasound for detecting congenital hip dysplasia was performed in 5970 infants, 2121 of whom were reinvestigated. Of those reinvestigated 726 belonged to the screened group not at risk examined as newborns, 70 were infants at risk first investigated as newborns and 363 were infants at risk first examined after the newborn period; the remainder were infants not at risk first investigated after the newborn period. Pathological findings were obtained in 7.7% of the entire group, in 3.9% of children at no risk, and in 5% of patients at risk. Deterioration of Graf's classification of types was seen in 3.2%. 13 children, 3 of the screened group and 10 of the nonscreened group developed hip dysplasia. None of them would have been missed since they were borderline type IIA on at least one side, which warranted mandatory follow-up.