A hip click on examination of the newborn hip is believed to be the result of a ligament or myofascial structure and thought to be benign. Some studies suggest a link between hip clicks and developmental dysplasia of the hip. The purpose of our study is to estimate the prevalence of ultrasound hip abnormalities in newborns with a hip click and an otherwise normal physical examination. Results. Ninety patients meeting inclusion criteria of a hip click with an otherwise normal physical examination underwent diagnostic ultrasound with a 17.8% prevalence of hip abnormalities found (95% confidence interval ±7.9% [range of 9.9% to 25.7%]). Our study had 64 (71%) females and 26 (29%) males. The prevalence of hip pathology for females was 18.8% (12 of 64 patients) and for males was 15.4% (4 of 26 patients). Thirty-three patients were found to have bilateral hip clicks on presentation, with 21.2% (7 of 33) of those patients found to have hip pathology on ultrasound (3 of the 7 had pathology of both hips). Six patients had a family history of hip dysplasia and 1 of these patients (16.7%) had pathology on ultrasound. The average age to hip sonography was 6.6 weeks. Conclusions. In all, 17.8% of newborns with a hip click were found to have hip abnormalities on ultrasound. The prevalence of hip pathology, on ultrasound, suggests that additional larger, prospective studies are needed to clarify the association between a hip click and abnormal ultrasound found at 6 weeks of age or greater.
The natural history of abnormal ultrasound findings in hips of infants under six months of age