Doctor K: Infant hip dysplasia can be treated

DEAR DOCTOR K: My baby has developmental dysplasia of the hip. What is this? How will it be treated?

DEAR READER:

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.

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. 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. Usually just one hip is affected, but in about 20 percent of children with this condition it affects both hips.

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.

Fortunately, treatment is usually effective, and the child does not have hip problems later in life.