Developmental dysplasia of the hip

Developmental dysplasia of the hip (DDH) is a condition where the "ball and socket" joint of the hip does not properly form in babies and young children.

It's sometimes called congenital hip dislocation or hip dysplasia.

The hip joint attaches the thigh bone (femur) to the pelvis. The top of the femur (femoral head) is rounded, like a ball, and sits inside the cup-shaped hip socket.

In DDH, the socket of the hip is too shallow and the femoral head is not held tightly in place, so the hip joint is loose. In severe cases, the femur can come out of the socket (dislocate).

DDH may affect one or both hips, but it's more common in the left hip. It's also more common in girls and firstborn children. About 1 or 2 in every 1,000 babies have DDH that needs treating.

Without treatment, DDH may lead to problems later in life, including:

• developing a limp
• hip pain – especially during the teenage years
• painful and stiff joints (osteoarthritis)

With early diagnosis and treatment, most children are able to develop normally and have a full range of movement in their hip.

Diagnosing DDH

Within 72 hours of giving birth, your baby's hips will be checked as part of the newborn physical examination. Another hip examination is carried out when your baby is between 6 and 8 weeks old.

The examination involves gentle manipulation of your baby's hip joints to check if there are any problems. It should not cause them any discomfort.

An ultrasound scan is usually recommended within a few weeks if:

• the hip feels unstable
• there's a family history of childhood hip problems
• your baby was born in the breech position (feet first with their bottom downwards)
• you've had twins or a multiple birth
• your baby was born prematurely – before the 37th week of pregnancy

Sometimes a baby's hip stabilises on its own before the scan is due.

Treating DDH

Pavlik harness

Babies diagnosed with DDH early in life are usually treated with a fabric splint called a "Pavlik harness". This secures both of your baby's hips in a stable position and allows them to develop normally.

Late-stage signs of DDH

The newborn physical examination, and the check at 6 to 8 weeks, aims to diagnose DDH early. However, sometimes hip problems can develop after these.

It's important to contact your GP as soon as possible if you notice your child develops any of the following symptoms:

• restricted movement in one leg when you change their nappy
• one leg dragging behind the other when they crawl
• one leg appearing longer than the other
• uneven skin folds in the buttocks or thighs
• a limp, walking on toes or developing an abnormal "waddling" walk

Your child will be referred to an orthopaedic specialist in hospital for an ultrasound scan or an X-ray if your doctor thinks there's a problem with their hip.

Preventing DDH

It's important to remember DDH cannot be prevented and is nobody's fault. A baby's hips are naturally more flexible for a short period after birth.

However, if your baby spends a lot of time tightly wrapped with their legs straight and pressed together (swaddled), there's a risk this may slow their hip development. Using "hip-healthy" swaddling techniques can reduce this risk. Make sure your baby is able to move their hips and knees freely to kick.

You can read about hip-healthy swaddling on The International Hip Dysplasia Institute website.