Closed reduction for developmental dysplasia of the hip

What is a closed reduction?

A closed reduction is the most common surgical treatment for children with developmental dysplasia of the hip (DDH) between the ages of 6 and 18 months. This procedure is performed on children for whom non-surgical treatment, such as the use of a Pavlik harness or fixed abduction brace, was not effective in treating DDH. In the closed reduction procedure, your child is taken to the operating room, placed under general anaesthesia, then the surgeon gently manipulates the dislocated hip to get the ball (femoral head) back into the socket (acetabelum). When the hip is in place your child is placed into a spica cast to hold it there.

What happens during the closed reduction procedure?

There are four main steps to a closed reduction. Each of these steps occurs after your child has been put under general anaesthesia.

Step 1. Adductor tenotomy

A very small incision (cut) is made in the groin and the surgeon releases the adductor tendon. By cutting this tight tendon, pressure on the soft surfaces of the hip is reduced, allowing the ball (femoral head) to stay in the socket (acetabulum) better after the hip has been reduced. Cutting the tendon is nothing to worry about – it heals very quickly, much like a groin pull in an athlete.

In some cases, a psoas tendon release is performed in addition to the adductor tenotomy. Similar to the adductor tenotomy, the psoas tendon release involves the surgeon cutting the psoas tendon to help the ball sit better in the socket.

Step 2. Hip reduction

With the muscles relaxed due to the anaesthesia and the released pressure on the joint from the adductor tenotomy, the surgeon is able to gently manipulate the ball at the top of the thigh bone (the femoral head) back into the hip socket (the acetabulum).

Step 3. Spica cast

The next step is to apply a hip spica cast to your child’s body. The cast goes from the upper chest down to the hips and then down both legs to the ankles (even if only one hip is affected). The goal of the cast is to hold the hip joint in place. The spica cast holds the legs in an abducted position (apart from each other) and allows the joint to heal. The constant contact between the femoral head and the socket is what triggers the growth of the acetabulum into the preferred shape.

Step 4. Imaging

After the spica cast has been applied, and while your child is still asleep, the doctor will take images of the hip using 3D fluoroscopy. This is similar to an X-ray that shows the new hip position in great detail and ensures that the femoral head is held in the correct position, to allow for proper hip formation as your child grows.

Going home after the procedure

A closed reduction is a single-day procedure so your child can go home the same day as the surgery. Your child is usually admitted to the ward for close observation for 5-6 hours after surgery to ensure that they are comfortable in their spica cast. This also allows the nurses plenty of time to teach you how to take care of your child in the spica cast.

Follow-up appointments after the procedure

Children usually spend between 3 and 4 months in the spica cast after closed reduction surgery, but this can vary depending on your child’s age at the time of surgery and the severity of hip dysplasia. To account for how much your child has grown since the surgery, the spica cast is typically changed at the halfway point of their treatment. During the spica cast change appointment, your child will be under general anesthesia and more images of the hip will be taken to check that the treatment is working.

The spica cast is removed in clinic once your child has worn it for the prescribed length of time. Afterwards, your child will typically be scheduled for follow-up appointments at 6 weeks, 12 weeks, 6 months and 1 year after cast removal. At these appointments, X-rays of the hips will be taken, and the doctor will examine the hip’s health and growth. Most children who had dislocated hips treated with surgery will need ongoing follow-up until they are fully grown to check that the hip continues to develop properly.

Complications of closed reduction surgery

Despite extreme care taken during the operation, there is still the possibility that complications could occur. During follow-up appointments, your child’s health-care team will look for signs of complications. You should also monitor your child at home for signs of complications and contact the health-care team if you suspect any of the following.

Nerve injury

An injury to a major nerve near to the hip is a very rare but serious complication of surgery. In general, nerve injuries can sometimes heal on their own but may also cause permanent disability of the hip and leg.

Vascular injury

An injury to a major blood vessel (artery or vein) near to the hip is a very rare but serious complication. This type of complication may cause permanent disability of the hip and leg.

Infection

There is a risk of infection with any surgical procedure, including this type of hip surgery. The risk of infection is very low, occurring in less than 1% of cases. No routine antibiotics are prescribed during this type of surgery as research has shown that a routine course of antibiotics does not reduce the risk of infection and may actually cause more harm.

Spica cast complications

It is very important to take good care of your child when they are in the spica cast otherwise serious complications can occur. A full description of how to care for the spica cast can be found in the article Caring for your child's hip spica cast. A spica cast that is too tight may cause pain and need to be released by the orthopaedic team. A tight cast would typically be identified in the first few hours after surgery. The skin under a cast can become very irritated by soiling of the cast, with urine or stool. Therefore, great care should be taken to keep your child clean throughout their time in the cast.

Growth disturbance (Avascular necrosis)

In approximately 15% of closed reduction cases, interruption to the blood supply of the hip joint (avascular necrosis or AVN) can occur which causes disturbance in the growth of the hip, specifically the femoral head (ball). It can take several years after the surgery to know whether such a growth disturbance has occurred. Fortunately, while these complications are not common, there are additional treatments available if growth of the hip is not as good as anticipated.

Re-dislocation

There is also the possibility that the hip may re-dislocate, meaning the ball may not stay in the hip socket and come back out of joint. This complication is very rare, occurring in less than 5% of cases. If re-dislocation occurs, the doctor will discuss further treatments and surgical procedures that may be necessary to put the hip back in joint, such as an open reduction or a hip osteotomy.