Introduction
Developmental dysplasia of the hip (DDH) is a condition that happens when a baby’s hip joint does not grow normally. The ball at the top of the thighbone is called the femoral head. In a normal hip joint, the femoral head sits inside the cup-shaped pelvis socket called the acetabulum. Tendons and muscles hold the femoral head in the socket.
The femoral head might move out of the socket if:
- If the tendons are loose or stretched
- the socket of the pelvis is too shallow
- the femoral head is too small.
Sometimes, the femoral head can become dislocated, meaning it easily moves in and out of the socket. If the femoral head moves out of the socket and stays out, the hip will not grow normally.
If DDH is not found before your child starts to walk, they may develop a “waddle”. As they grow older, the hip can become still and painful, and they may develop arthritis. Arthritis is a condition where there is ongoing swelling and pain in the joint.
Signs and symptoms
Signs that your child might have DDH include:
- uneven skin creases near their bottom
- not being able to move their leg normally
- leaning to one side when they stand or walk, which might be caused by uneven leg length
- not sitting by 10 months of age
- not walking by 18 months of age
- having a foot that is turned out
- walking with a waddle
- having difficulty parting their legs for nappy changes.
Diagnosis
All children need regular hip checks until they finish growing.
Typical ages for checking are:
- at birth
- one week after birth
- 6 weeks after birth
- 6 months after birth
- when they begin to walk.
DDH can still be found in older children.
X-rays are used to look at your child’s hips after six months of age if they are showing signs of DDH.
Treatment
Treatment of DDH depends on how old your child is and how severe their hip development is. Most commonly, babies are treated either with a Pavlik harness, rhino brace or custom made brace as specified by the medical team. The wearing regime will be determined by your doctor.
The Pavlik Harness
Babies with DDH do very well when treated with a Pavlik harness. A Pavlik harness is a soft brace that stays on for six to ten weeks to help the hips grow normally.
Most babies have average hip growth after they finish treatment in the Pavlik harness. Some babies will still have hip problems as they grow. Babies who do not improve when treated early with the Pavlik harness will need surgery.
Surgery
Surgery may be needed for children who are older than six months or babies whose hips do not improve after wearing the Pavlik harness.
The type of surgery needed will depend on the age of your child and the severity of their hip development. Your child’s doctor will discuss different types of surgery with you.
After surgery, your child’s hips will be held in place with a lower body cast called a hip Spica. This cast will stay on for a few months and will need special care.
A small number of children do not improve after surgery for DDH. They may need more surgery between 2 - 4 years of age.
Management
Risk factors
Some things may increase the likelihood that your baby will have DDH. These include:
- being born in the breech position, feet first
- being female
- oligohydramnios – a condition where there is low fluid around the baby during pregnancy
- birth weight over 4kg
- being a first-born baby
- being overdue for birth by more than 2 weeks
- a family history of DDH
- other tendon problems like talipes equinovarus, known as club foot and torticollis, known as neck stiffness.
Newborn hip checks are very important for babies, especially if they are at risk of DDH.