This is the most common treatment for babies between the ages of 6 and 24 months. The doctor physically manipulates the hip joint to get the ball back into the socket while the baby is asleep under general anesthesia.
Occasionally, before the procedure, a few weeks of traction is used to stretch and relax the child’s ligaments before attempting the closed reduction.
After the child is put to sleep with anesthesia, there are generally four steps involved in a closed reduction procedure:
Closed Reduction Procedure Outline
Dye is injected into the hip joint with a needle so the inside of the joint can be seen on x-rays. This allows the doctor to verify the hip reduction and helps identify any potential problems that may prevent the hip from going into place.
The doctor makes a very small opening in the groin and surgically releases the adductor tendon. This tendon is normally very tight. Releasing the tendon takes pressure off the soft surfaces of the hip and helps keep the ball in the socket after the hip reduction. The tendon heals very well, growing back like it does in an athlete that has a groin pull.
The doctor physically manipulates the ball at the top of the thigh bone (femoral head) back into the hip socket while monitoring progress by x-ray. The doctor uses x-rays to verify that the hip is in the best possible position before casting.
The child is put into a hip spica cast. This keeps the hip in the newly aligned position while the joint heals, and encourages proper formation of the hip joint as the child grows.
Follow-Ups After Closed Reduction
Usually the spica cast is changed every 6 weeks until the child has been in the cast for 3-6 months. Improvement in the hip may not be realized until the first cast change. At the cast changes, an arthrogram is often performed to check on the progress of the hip joint. The total time in the cast depends of the appearance of the hip on x-ray with the arthrogram.
When the final cast is removed, the child is normally placed into a hip abduction brace for several more weeks. Since the child has been in a stiff cast for so long, he or she has temporarily lost muscle tone and some flexibility. The brace provides extra support, as a transition stage, as the child regains the strength and flexibility. During this time it is important to follow your doctor’s prescription, which will normally be to wear the brace at all times, except for baths, in the beginning. The brace allows for more hip movement than a cast, but the hip still needs time to grow and become more stable before the brace support is taken off.
After a few weeks in the brace, the doctor will begin to allow more time out of the brace for the child to further regain strength and movement. Generally, children seem to tolerate this process very well and they quickly catch up to other children in all of their activities.
After a year, when the hip returns to normal, it should be impossible to tell children who spent time in a cast from children who were never in a cast. This process is not always successful and sometimes problems develop during or after treatment.
Risks of Closed Reduction
Sometimes this procedure is delayed until visible bone in the ball of the hip (head of the femur) is seen on x-rays. There is some concern that the hip is too soft before this bone appears and the closed reduction may cause damage to the growth of the hip. On the other hand, waiting until the child is older may cause more stiffness and more abnormality of the hip joint, reducing the effects of treatment.
There is currently no scientific agreement that waiting for this bone to appear helps protect the hip from damage during reduction. Damage to the blood supply of the hip or damage to the growth plate can occur even during gentle attempts at closed reduction. Further, there is no way to know if this has happened for at least 6 months after the closed reduction. Fortunately, damage is not common but requires additional treatment later if it occurs.
The hip may not stay in the joint after the anesthesia wears off even though the child is in a spica cast. In some cases the doctor will recommend an MRI or CT scan in addition to x-rays of the hip after the child is awake to make sure the hip stays in the joint.
While surgery for your child may seem scary, treatment (surgical or non-surgical) gives the child the best chance for a normal hip and most problems that arrise can be treated if things don’t turn out as expected.