Natural history of ultrasound hip abnormalities in clinically normal newborns.

One hundred one clinically normal newborn hips showed varying degrees of sonographic hip dysplasia according to the classification of Graf. None were treated, and after +/- 6 months, radiographs showed that only four had definite dysplasia. Of these, three had had risk factors such as breech delivery or familial predisposition. Forty-three other clinically normal newborn hips showed ultrasonic instability, which spontaneously corrected. The severity of ultrasound dysplasia at birth was not related to ultimate development of the hip. Our results indicate that ultrasound should not be performed as a general screening procedure in clinically normal newborns.