DEAR DOCTOR K: My baby has developmental dysplasia of the hip. How will it be treated?
DEAR READER: Because I'm not a pediatrician, I haven't seen a baby with developmental dysplasia of the hip since I was in medical school. But I talked with pediatrician colleagues here at Harvard Medical School and refreshed my memory.
Our hips are designed to support our full weight while allowing movement in all directions. To accomplish this, the rounded top of the thigh bone (femur) fits into a cup-shaped socket in the pelvis called the acetabulum. The “ball” of the femur sits inside the socket. (I've put an illustration of the hip joint on my website, AskDoctorK.com.)
In developmental dysplasia of the hip, the ball at the top of the femur moves in and out of the socket either partway or all the way. That's not supposed to happen: It makes the hip unreliable in supporting the baby's weight.
The ball of the femur slips in and out of the socket because the ligaments that hold the two bones together are very loose or because the cup-shaped socket is not deep enough. This condition usually is present at birth, but it can develop after birth, during infancy or childhood. In about 20 percent of children, it affects both hips.
The condition is more common in babies who were breech deliveries. It also seems to run in families. It happens more often in little girls than in little boys, and more often in firstborn infants. We don't know why.
Doctors routinely check for developmental dysplasia of the hip in newborns and at follow-up well-baby visits. If the doctor feels unusual movement of the hip, he or she will use ultrasound or X-rays to confirm the diagnosis.
Left untreated, developmental dysplasia of the hip can lead to a shortened leg, arthritis, difficulty walking and long-term pain. But with early treatment, most children can walk normally and have normal hip function.
Treatment depends on the child's age:
Newborns usually wear a special device, such as the Pavlik harness or the Frejka splint. These devices keep the top of the femur in the socket the right way. The hip ligaments gradually tighten and the hip joint usually stabilizes.
For infants age 1 month to 6 months, the doctor will try a harness or splint. If these devices don't help, the doctor will consider gently (and nonsurgically) putting the head of the femur in place while the child is under anesthesia. This is called a closed reduction. The child then wears a body cast (spica cast) until the hip joint is normal.
Most children age 6 months to 2 years can be treated with closed reduction and a spica cast. Some require open surgery.
For children older than 2 years, surgery is often needed, followed by a spica cast.
Dr. Komaroff is a physician and professor at Harvard Medical School. To send questions, go to AskDoctorK.com, or write: Ask Doctor K, 10 Shattuck St., Second Floor, Boston, MA 02115.
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