Is ultrasound screening for DDH in babies born breech sufficient?

Abstract

To review our incidence of developmental dysplasia of the hip (DDH) in breech infants referred for ultrasound screening and to determine if subsequent follow-up radiographs are necessary in these patients with normal clinical and ultrasound examinations. A review of the clinical data and imaging studies of all children with the risk factor of breech presentation that were referred for orthopedic evaluation over a 5-year period was conducted. All patients were examined by a fellowship-trained pediatric orthopedic surgeon and all ultrasounds were done at approximately 6weeks of age by an experienced ultrasonographer. Ultrasounds were evaluated using the dynamic method as described by Harcke. As per our protocol, all patients with normal screening ultrasounds were brought back for a final clinical examination and radiographic check at 4-6months. Acetabular dysplasia was indicated by radiographic parameters-if there was severe blunting of the sourcil, abnormal acetabular index for age, or if there was significant asymmetry of acetabular indices side-to-side-in the setting of clinical parameters-if there was greater than 10° difference in side-to-side abduction or symmetric abduction of less than 60°. Three hundred patients with the risk factor of breech presentation were included. Thirty-four patients had clinically unstable hips; 266 had clinically stable hips and were screened by ultrasound. Sixty-four percent were female and 36% were male. Twenty-seven percent of these breech patients had abnormal screening ultrasounds and were subsequently treated. Of the remaining 73% with normal ultrasounds, who were returned per protocol at a mean of 5months, 29% had evidence of dysplasia and underwent treatment. The diagnosis of dysplasia following a normal ultrasound was based on both radiographic and clinical parameters. Of the hips treated with a Pavlik harness, 62% had acetabular indices at least two standard deviations from the age-corrected average versus 26% of patients not treated. The average length of follow-up was 10months. Retrospectively, we found that, at approximately 6weeks of age, ultrasound screening of breech patients with clinically stable hips produces an incidence of DDH of 27%. In those patients with a normal ultrasound, 29%, at 4-6months radiographic follow-up, were found to have dysplasia requiring treatment. This data supports breech as the most important risk factor for hip dysplasia and we, therefore, recommend careful and longitudinal evaluation of these patients with: a careful newborn physical examination, an ultrasound at age 6weeks, and an anteroposterior (AP) pelvis and frog lateral radiograph at 6months, as the risk of subsequent dysplasia is too high to discharge patients after a normal ultrasound.