Developmental Hip Dysplasia (DDH) occurs in 1 in 1000 births. In a normal hip the upper end (ball) of the femur (thigh bone) fits firmly into the hip socket. DDH refers to different abnormalities of the hip noted in infancy when the hip joint has not formed normally. This may range from a mildly unstable hip in an infant to an infant that is born with a completely dislocated hip. DDH is screened for from the time an infant is born until they are walking, in hopes of picking up any abnormality at a young age.
The majority of babies with DDH are female (75%), and it is also more common in infants who are in the breech (butt down) position during the 3rd trimester of a woman’s pregnancy. Other risk factors for DDH include: a family history of DDH and improper swaddling of an infant.
You may notice that your pediatrician examines your baby’s hips at every visit. They will perform the Ortolani maneuver and the Barlow test where the doctor is trying to see if they can feel a dislocated or unstable hip. In these tests they are actually putting pressure on the hip to check for a “click or clunk” which suggests a hip problem or instability.
For female babies who have been breech it is recommended that they not only have a physical exam checking for DDH, but that they also undergo an ultrasound of the hips after 6 weeks of age and prior to 6 months. Ultrasound for male babies who have been breech is not “routinely recommended” but may be ordered if the baby has any signs of hip instability.
The incidence of hip instability and dysplasia seems to have also increased since parents began routinely swaddling their babies. It is now recommended that babies sleep in a sack rather than having them swaddled with their legs extended. For the hips to develop normally a baby needs to be able to move their legs around which will drive the femur into the hip socket, so that the socket gets deeper. A shallow, flat hip socket may lead to hip dysplasia.
In most cases that are detected early the treatment is a brace called a Pavlik harness that will hold the femur into position within the hip socket. A baby stays in the harness for 6-12 weeks in order that the hip joint will develop normally. For babies that may develop hip dysplasia after 6 months of age an orthopedist will probably recommend closed reduction to put the hip back into place. This is done under anesthesia and then the baby is placed in a cast that also pushes the femur into the hip socket. The baby may have to wear this cast for 4 - 5 months.
Every time your pediatrician takes off your baby’s diaper during their exam it is not really about a diaper change. That hip exam is really important!