Developmental dysplasia of the hip
Developmental Dysplasia of the Hip (DDH) is the name used to describe a range of ways a baby’s hip might not develop normally. In the past the name Congenital Dislocation of the Hip (CDH) was often used, but not all hip joints that are growing abnormally are dislocated. Dysplasia means growing abnormally.
Having an unstable or dislocated hip will cause problems in later life if it is not treated.
Development of the hip
Normal hip For the hip joint to grow normally the ball shaped head of the thigh bone (femur) needs to be inside the cup shaped socket on the side of the pelvis (called the acetabulum).
The head of the femur is held in place by ligaments, muscles and a joint capsule.
Abnormal development If the head of the femur is not held tightly in place, the socket may be flatter than usual, making the joint less stable and the head of the femur may be able to move in and out of the socket.
If the head of the femur loses contact with the socket and stays out of the joint, this is called dislocation.
Causes of dysplasia
The causes of a hip joint not developing normally are not fully known.
There are things that make it more or less likely that DDH will happen.
Research done in South Australia showed that:
- a baby in the breech position before birth is 10 times more likely to have DDH than other babies
- a female baby is 4 times more likely to have DDH than a male baby
- a baby who has little fluid around it before birth has 4 times the risk
- a big baby (over 4.5 kg) has 2 times the risk
- a first born baby has 2 times the risk
- babies born into families where another baby had DDH and babies who had other birth defects such as foot abnormalities also have an increased risk.
Australian research has reported that 1% of babies have DDH.
Checking hips of babies and infants
All babies, including those who do not have any risk factors, should have their hips checked several times in the first year of their life, and all children should have the way that they walk checked soon after they start to walk. Young children who have a dislocated hip that has not been discovered before they start to walk have an unusual ‘waddling’ way of walking (gait).
A doctor, midwife or community child health nurse should check a baby’s hips:
- soon after birth
- on discharge from hospital or about a week after birth
- around 6 weeks
- around 6 months (the hip check will be done in a different way at this time compared to the way the hip is checked at an earlier age).
Sometimes a movement within the hip can be felt (a ‘clunk’) and this may mean that the hip is not stable and needs to be checked by a doctor. Sometimes a ‘clicking’ sound is heard. This happens quite often and many times the hip is not unstable, but it still needs to be checked by a doctor. If the hip of an older baby (over about 3-4 months) is dislocated the baby’s leg will not move as much as normal, and this also needs to be checked by a doctor.
What is done next?
If it seems possible that a baby might have an unstable hip, the baby needs to be seen by a doctor who can examine the baby and if needed refer the baby to an orthopaedic surgeon as soon as possible, and then the baby is put into a splint.
- The splint will hold the hip in the best position for normal hip development.
- The splint will be put on by a physiotherapist, who will explain how to look after the baby and the splint. The splint has to stay in the right position all of the time. It is not to be taken off even for bathing.
- Wearing a splint does not alter the baby’s normal development.
- Ultrasound is used to make sure that the baby’s hip is in the right position while the splint is on, and after the splint has been taken off. This will show whether the acetabulum (the socket) is developing normally.
When this treatment is started as soon as possible after birth, most hips develop normally, further treatment is not needed and children will live a normal active life.
Surgery may be needed if the hip does not stay in place in the splint, or if the child is older (eg over 6 months) when the dislocated hip is found.
When babies are wrapped tightly with their legs straight the hip is not in the best position for normal growth. The topic ‘Wrapping babies’ shows how to wrap a baby so that the legs are able to bend at the hips.
- Pamphlet ‘Developmental Dysplasia of the Hip (DDH)’,
- Neonatal Hip Instability Care Pathway
Chan A, McCaul KA, Cundy PJ, Haan EA, Byron-Scott R, ‘Perinatal risk factors for developmental dysplasia of the hip’ Archives of Diseases in Childhood, March 1997, Vol 76, No 2, pF94-F100.
Chan A, Cundy PJ, Foster BK, Keane RJ, Byron-Scott R, ‘Late diagnosis of congenital dislocation of the hip and presence of a screening programme: South Australian population-based study’, The Lancet, Vol 354, October 30 1999.
The Children’s Hospital, Westmead (NSW) ‘Developmental Dislocation of the Hips’
The information on this site should not be used as an alternative to professional care. If you have a particular problem, see a doctor, or ring the Parent Helpline on 1300 364 100 (local call cost from anywhere in South Australia).
This topic may use ‘he’ and ‘she’ in turn – please change to suit your
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