Imaging of developmental dysplasia of the hip.

Careful clinical examination remains the primary and most important way of diagnosing developmental dysplasia of the hip (DDH) in newborn infants. Repeated examinations during the first year are important to diagnose DDH subsequent to the newborn period. Sonography can detect cases of clinically silent DDH. Targeting high-risk infants for supplemental ultrasound screening at 4 to 6 weeks of age increases diagnosis of DDH and at significantly less expense than widespread screening. When sonography is not available, a pelvis radiograph at 3 months should be obtained in high-risk infants. Sonography also is used to monitor hip position and acetabular development in children undergoing harness treatment. Computed tomography and magnetic resonance imaging are reserved for children with more severe dysplasia, often as preoperative studies to help orthopedic surgeons to select the appropriate procedure.