Which imaging modality is used to assess DDH in a newborn as a preferred screen?

• A. Frog leg X-ray
• B. Plain hip X-ray
• C. Ultrasound of the hip
• D. CT of the hip

Answer: (C)

Ultrasound of the hip is the preferred screen for DDH in a newborn because it can visualize the cartilaginous parts of the hip before bone ossification occurs. This allows early detection of instability or dysplasia that a plain X-ray cannot reliably reveal in very young infants. Ultrasound provides dynamic, real-time assessment of the femoral head in relation to the acetabulum and lets clinicians use standard criteria (such as Graf’s method) to classify hips. It is also safe and radiation-free, making it ideal for newborn screening. Plain X-ray relies on bone that isn’t yet ossified in newborns, so it often doesn’t show the problem and can be misleading. CT involves significant radiation and is not used for initial screening. A frog-leg X-ray is another radiographic view but still exposes the infant to radiation and has limited sensitivity in newborns. Thus, ultrasound of the hip best serves as the initial screening tool.