Outcome of ultrasonographic hip abnormalities in clinically stable hips.

A retrospective review was performed of 192 newborn hips in 112 patients referred for hip evaluation. The average age at presentation was 12.7 days, with average radiographic follow-up of 15.9 months. Inclusion criteria for our study were a normal physical examination of the hip without evidence of instability and an ultrasound examination that was considered abnormal. Pavlik harness treatment was chosen at the discretion of the treating physician. At final follow-up, dysplasia was defined as greater than two standard deviations above the mean acetabular index (AI) for age. Group I consisted of 43 hips that had Pavlik treatment, and group II consisted of 149 hips that did not receive treatment. There was no difference in these two groups with respect to risk factors for dysplasia or the initial abnormalities seen on ultrasound evaluation, although patients in group I had less coverage of the femoral head during stress maneuvers. No hip in group I and two (1.3%) hips in group II were considered dysplastic (AI > 2 SD) at final radiographic follow-up (p > 0.10). There was no correlation between the severity of the ultrasound abnormality at birth and the subsequent presence of dysplasia (p > 0.10). The two hips considered dysplastic on radiograph were not being actively treated. When the hip examination of a newborn hip younger than 1 month is normal, a screening ultrasound does not appear to predict accurately subsequent hip dysplasia. In this specific setting, an initial screening ultrasound may be too sensitive and does not appear warranted.