For a 6-week-old infant with positive Barlow and Ortolani maneuvers, which test should be ordered to assess DDH?

For a 6-week-old infant with positive Barlow and Ortolani maneuvers, which test should be ordered to assess DDH?

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

Answer: (C)

When a 6-week-old has positive Barlow and Ortolani maneuvers, the imaging choice is ultrasound of the hip. At this age, the femoral head and acetabulum are mostly cartilaginous and not yet ossified, so X-rays don’t show DDH reliably. Ultrasound can visualize the cartilaginous joint surfaces, assess the relationship of the femoral head to the acetabulum, and allow dynamic evaluation of stability as the hip is manipulated. It is highly sensitive for detecting DDH in young infants and can monitor development or response to treatment without exposing the baby to radiation. Plain radiographs become more informative after ossification progresses (later in infancy), while CT involves unnecessary radiation and is not used as a first-line study in this setting.

When a 6-week-old has positive Barlow and Ortolani maneuvers, the imaging choice is ultrasound of the hip. At this age, the femoral head and acetabulum are mostly cartilaginous and not yet ossified, so X-rays don’t show DDH reliably. Ultrasound can visualize the cartilaginous joint surfaces, assess the relationship of the femoral head to the acetabulum, and allow dynamic evaluation of stability as the hip is manipulated. It is highly sensitive for detecting DDH in young infants and can monitor development or response to treatment without exposing the baby to radiation. Plain radiographs become more informative after ossification progresses (later in infancy), while CT involves unnecessary radiation and is not used as a first-line study in this setting.