Normative Radiographic Parameters and Growth Curve of Hips Less Than Six Weeks of Gestational Age Using Ultrasound

Both hips will be examined. The diagnostic examination for developmental dysplasia of the hip (DDH) incorporates 2 orthogonal planes: a coronal view in the standard plane at rest and a transverse view of the flexed hip at rest. It is acceptable to perform the examination with the infant in a supine or a lateral decubitus position. The anatomic coronal plane is approximately parallel to the posterior skin surface of an infant. The imaging plane is through the deepest part of the acetabulum (which includes visualization of the triradiate cartilage and the ischium posteriorly), the resulting image will be a coronal view in the standard plane. The standard plane is defined by identifying a straight iliac line, the tip of the acetabular labrum, and the transition from the os ilium to the triradiate cartilage. Acetabular morphology is assessed in this view and may be validated by measuring the acetabular alpha angle (≥60°). The femoral head coverage by the bony acetabulum should be \>50%.