Consistency of Indices Obtained via Hip Medial Ultrasound and Magnetic Resonance Imaging in Reduction and Spica Cast Treatment for Developmental Dysplasia of the Hip.

Children younger than 18 mo with developmental dysplasia of the hip (DDH) were treated with reduction and spica cast. X-Ray, computed tomography or magnetic resonance imaging (MRI) was used to evaluate reduction effectiveness. This study explored the hip medial ultrasonography method and anatomic structure sonograms. Twenty-eight children with DDH were enrolled. A total of 51 hips (24 left hips /27 right hips) were measured, including 30 affected hips and 21 normal hips. Various indices, including femoral head diameter (DIA), triradiate cartilage-femoral distance (TFD), acetabular-femoral distance (AFD) and ilium-femoral distance (IFD), were measured in the acetabular median coronal plane of ultrasound and the median coronal plane of MRI. The intra-group correlation coefficients for DIA, TFD, AFD and IFD were 0.968 (95% confidence interval: 0.917-0.985), 0.959 (0.929-0 976), 0.923 (0.869-0.955) and 0.950 (0914-0.971), respectively. Hip medial ultrasound and MRI exhibited good consistency. It is feasible to use hip medial ultrasound to evaluate the reduction of DDH in infants and children after spica cast.