Can you treat hip dysplasia without surgery?
If hip dysplasia is diagnosed early it can often be successfully treated without surgery using either a harness or a plaster cast to gently position the hip correctly (see blog article Childhood hip dysplasia: non-operative treatment). However, if the dysplasia is diagnosed later when the child is of walking age, the chances of successful treatment without surgery decrease. Earlier diagnosis helps to avoid surgery which is why any baby born with risk factors for hip dysplasia has an ultrasound scan at 4-6 weeks of age.
When hip dysplasia is diagnosed in children of walking age (8 months +), the chances of being able to manually position the hip into the joint reduce significantly. This is usually due to two factors. Firstly, there may be structures within the hip blocking its ability to achieve a normal relationship between the ball and socket. An arthrogram (dye injection study) is usually the best means to determine if the ball (femoral head) can be manually positioned into the socket (acetabulum) so that it is deep and stable. If the arthrogram suggests that the ball can not sit deeply in the socket then it will remain dislocated.
The second concern, is that in the dislocated hip, the socket fails to deepen in the first year of life. This lack of development means the socket remains shallow. In such cases it may be possible to place the ball of the hip joint into the socket but it can easily re-dislocate even in a plaster cast. If the ball of the hip joint is unstable in the socket, then surgery is the best way to stabilise the hip.
Surgery is required to achieve two objectives –
- Remove any obstructions to place the ball deeply into the socket and
- Correct the shallowness of the socket and other factors which might cause the hip to re-dislocate. Therefore surgery is only considered if non-operative techniques can not get the ball into the socket or that the ball can be placed into the socket but keeps slipping out.
Contact Dr. Assad for surgical treatment options for Childhood Hip Dysplasia
What surgical procedures are used to treat the hip dysplasia?
The exact surgical procedure depends on the age of the child, the severity of the hip dysplasia and the arthrogram (dye study) findings. The key techniques include:
- Arthrogram – this is where dye is injected into the hip so that we can determine on the x-ray whether the hip is shallow and whether it is unstable.
- Open reduction – the hip is opened surgically through a “bikini”incision in the groin crease. Any obstructions preventing the ball from going into the socket are addressed and the ball is taken from the dislocated position and placed into the socket.
- Femoral osteotomy – the femur bone is shortened to minimise pressure on the ball when it is placed in the socket. The ball is made up mainly of cartilage which is soft and easily damaged. Shortening the femur bone reduces the tension in the joint and minimises the risk of the ball being damaged. The bone is fixed with a metal plate and screws. The bone removed from the shortening is used in the pelvic osteotomy.
- Pelvic osteotomy – the socket is re-shaped to make it deeper so that the ball is more stable once placed back inside. This is done by dividing the pelvic bone to lever the “roof” down over the ball so that it can’t dislocate easily. The bone from the femoral shortening is used to fill the gap.
- Capsuloraphy – once the ball is deep in the socket, the capsule is closed over the ball to seal the hip joint and help stop it dislocating.
- Hip spica – a plaster cast is applied over the hips to keep the hip in place while everything heals. The plaster cast (hip spica) is kept on for 6 weeks.
What are the risks of surgery?
General risks of surgery include infection, need for blood transfusion, nerve or vessel injury and risks of anaesthesia. The risk of infection in childhood hip surgery is less than 1% and antibiotics are given during the perioperative period to minimise this risk.
Depending on the scale of surgery some patients may require a blood transfusion during or after surgery. This is usually due to blood loss from the femoral and pelvic osteotomies.
The risk of nerve or major blood vessel injury is less than 1%. Specific risks to the hip during surgery include re-dislocation, avascular necrosis (damage to the ball in the joint) and residual dysplasia (socket remains shallow during development).
Although the accepted risk of re-dislocation can be as high as 10% in the literature, the addition of pelvic and femoral osteotomies improves the stability of the hip and reduces this risk further. It is best to ask your surgeon about the risk of re-dislocation in their clinical practice.
Avascular necrosis is where damage to the ball of the joint (femoral head) occurs following treatment. It can occur with non-operative or operative treatment but is more common in operative treatment. A common cause of avascular necrosis is excessive pressure on the ball in the socket following treatment.
This damages the blood supply of the hip and over time the ball develops an abnormal shape. It can not be reversed and the best strategy is to try to avoid it occurring. Shortening of the femur (thigh bone) at the time of surgery to reduce the tension within the hip joint helps minimise the risk of avascular necrosis.
Residual dysplasia is where the socket remains shallow despite the surgery to place the ball back in the socket. If severe enough this can cause the hip to re-dislocate. In less severe cases, the ball remains in the socket but the coverage by the socket remains deficient. It becomes more obvious with the passage of time and is often the reason why many parents are counselled that there child will need further surgery in the future.
Residual dysplasia often occurs when an open reduction is done without a pelvic osteotomy or if the pelvic osteotomy has failed to adequately address the shallow socket. A pelvic osteotomy at the time of open reduction using a powerful corrective technique known as the Dega osteotomy can help avoid this. By correcting the shallow socket in the first operation, the hope is that we can avoid future corrective hip surgery as the child grows older.
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