A comparison of ultrasonography and radiography in the management of infants with suspected developmental dysplasia of the hip.

The aim of this study was to determine the sensitivity and specificity of plain radiography in the detection of developmental dysplasia of the hip, using hip ultrasonography as a reference standard. A retrospective review was made in 44 infants ranging in age from 4 weeks to 50 weeks (mean age: 21.7 weeks). Both radiographic and ultrasonographic images were obtained for 86 hips. Radiography and ultrasonography were found to be significantly correlated in terms of classification of developmental dysplasia of the hip presence or absence (p < 0.0001, Fisher's exact test). With ultrasonography accepted as the standard for the diagnosis of developmental dysplasia of the hip, radiography had a sensitivity of 61% and a specificity of 87%. The results of this study suggest that the two imaging methods give similar overall results, but that low grade dysplasia detected on ultrasonography may go undetected on radiography.