Developmental dysplasia of the hip: Clinical sciences

Developmental dysplasia of the hip, or DDH for short, is a condition associated with misalignment of the femoral head and acetabulum, which results in an unstable joint.

Normally, the femoral head sits within the acetabulum, allowing both to grow together over the first few years of life to create a ball and socket joint. But, when the acetabulum is too shallow, the femoral head is unable to stay in place, and both of these bony structures grow independently. If this persists, eventually they will no longer fit together.

It’s critical to screen all infants for DDH for early identification and treatment, as early treatment ensures better functional outcomes and reduces the risk of hip joint osteoarthritis. Screening for DDH is often done during well-child visits via the hip exam, which differs based on whether the child is younger or older than 6 months.

For infants under 6 months old, you should perform a thorough physical exam and check for any abnormalities on the hip exam using the Ortolani and Barlow maneuvers. Both maneuvers begin with the infant on their back with their hips flexed. The Ortolani maneuver involves slowly abducting the hip and then gently pressing upwards on the lateral thigh.

If the femoral head is dislocated, the Ortolani maneuver will push the femoral head up and into the acetabulum, making a “clunk.” This is also known as the Ortolani clunk. On the other hand, the Barlow maneuver involves slowly adducting the hip and then gently pressing down on the knee. If there’s hip joint instability, the femoral head will be pushed down and out of the acetabulum, making a “click.” This is also called the Barlow click.

If the infant’s hip exam is normal, meaning the Ortolani and Barlow maneuvers are negative, you should assess for DDH risk factors. These include a family history of DDH, as well as breech orientation during pregnancy but after 34 weeks of gestation, regardless if an external cephalic version was successful.

If the infant has no risk factors, no further workup is needed, so you can continue with routine physical exam screenings at future well-child visits. However, if DDH risk factors are present, you should order a bilateral hip ultrasound.

If the ultrasound is normal, you can continue with routine physical exam screenings at future well-child checks. On the flip side, if the screening ultrasound detects hip instability, asymmetry, subluxation, or even dislocation of the femoral head outside of the acetabulum, diagnose DDH. Once you diagnose DDH, you should consult your surgery team, more specifically a pediatric orthopedist, who may recommend an abduction splint, like the Pavlik harness.