Children with DDH have a thighbone (femur) that does not sit firmly in the hip socket. It should be treated from a very early age.

Overview

What is DDH?

DDH is where the thighbone (femur) is not firmly in the hip socket. The socket or acetabulum is shallow, so the thighbone doesn’t fit fully inside and this leads to looseness or instability. There are different levels to this:

• Dislocated – this is the most severe form and the head of the thighbone is completely dislocated or out of the socket
• Dislocatable – where the head of the thighbone lies within the socket, but it can easily be pushed out during a physical exam
• Subluxatable – in more mild cases, the head of the thighbone is loose in the socket. It can’t be dislocated during a physical examination, but the bone can be moved

Cause

DDH affects around one to two babies per 1,000 each year. It can be genetic and tends to runs in families. Furthermore, it can be present in either hip but does usually affect the left. Girls are more predisposed to it, as are firstborn children and babies born breech. Another risk factor is a low level of amniotic fluid during pregnancy.

Diagnosis

As mentioned above, a physical exam may show that the thighbone can be pushed out from the socket. However, further investigations are needed. What these are will depend on the age and size of the child. If the child is under the age of six months, then an ultrasound may be used. Otherwise, an X-ray may be used.

Symptoms

There are a few physical symptoms that may indicate DDH, however some babies won’t show any physical signs of it.

• Legs are different lengths
• There are uneven skin folds on the thigh
• The child appears to be less mobile or flexible on one side
• If walking, there may be a limp, walking on the toes or the child may have a slight waddle

Treatment

Overview

The treatment of a child will depend on their age. This is because if it is picked up later then it may be more complicated and lead to pain or osteoarthritis by early adulthood. Other problems may include a difference in leg length or a limp.

There may be some children who receive treatment at the right time, but who will still go on to develop some problems. Ongoing X-rays and monitoring will help to reduce this risk or to identify at an early point as to whether further treatment is needed.

Newborns - up to four months old

A Pavlik harness is used – this is a soft positioning brave as helps to hold the hip in the proper position, but still allows the legs to move. Parents can be shown how to use it while still doing normal daily care for the child, such as bathing or dressing.

Six months up to one year

For slightly older babies, a body cast may be used to hold the hip in place. This is also called a spica cast and is a closed reduction procedure. The procedure is carried out under an anaesthetic as it is important the doctor can gently put the thighbone in the proper position first. Again, parents are supported on looking after a child in a cast.

Six months and older

Should a closed reduction procedure have been carried out but was unsuccessful, then the next treatment path might be open surgery. A surgeon will make an incision at the baby’s hip, to allow them to clearly see the bones and soft tissues. The thighbone might be shortened, or a pelvic bone cut, in order to fit the bone fully into the socket.

To ensure that the bones are in the correct position, X-rays will be carried out during the operation. Following this, a cast will be used to keep the hip in the correct position.

Helpful resources

• Steps: DDH