What is Developmental Dysplasia of the Hip (DDH) ?
DDH is a condition where the ball and socket hip joint fails to develop normally. It can occur before birth or in the first months of life. If the ball (femoral head) is not held correctly in place, the socket (acetabulum) may be more shallow than usual. Sometimes this makes the joint less stable and the ball may slide in and out of the socket. This is called a “dislocatable” or “subluxatable” hip. If the ball loses contact with the socket and stays outside the joint it is called a “dislocated hip”. The severity of the condition varies and it is the commonest paediatric orthopaedic condition affecting the hip.
Is there variation in normal hip development?
About 20 in every 1,000 children are born with a hip which is not stable at birth. This means that the hip may displace slightly or completely from its socket. Although many will have immature hips that will get better without treatment, in about 2 in 1000 the problem is worse or persists causing varying levels of significant hip dysplasia requiring treatment.
What if DDH is missed or untreated?
Missed or untreated DDH may lead to pain in the hip (usually during teenage years) and the development of osteoarthritis (wear and tear arthritis) in adult life. Severely damaged hips may need replacement as a young adult so it is therefore very important to detect the condition as early as possible and treat it effectively.
Which babies are most likely to get DDH?
It is more commonly found in the left hip than the right but both can be affected. It is seen more frequently in girls and first born babies and those who have a first degree affected relative (mum, dad, brother or sister) and those with additional risk factors.
What are the additional risk factors for DDH?
- Breech after 36 weeks (regardless of whether breech or head first at delivery)
- Oligohydramnios (reduced amniotic fluid) after 36 weeks
- Talipes (club foot)
- Multiple pregnancy (twins, triplets etc)
- Premature birth
How do you test a baby’s hips for DDH?
All children in the UK have their hips checked at birth, at six weeks, eight months and at two years. All babies’ hips are checked at birth and at 6-8 weeks as part of a national screening programme called the Newborn Infant Physical Examination (NIPE). The baby’s hips are gently manipulated to see if they are correctly in joint by tests known as the Ortolani and Barlow Tests. If the examination is abnormal then they will have a DDH Hip Ultrasound Scan. Even if the physical examination is normal NHS guidelines say that any baby’s with additional risk factors should have an ultrasound examination within 6 weeks any way as ultrasound is the gold standard test for detecting hip problems in babies under 6 months
Will the routines tests always pick up babies with DDH?
No. Unfortunately In more than half of cases there are no identified risk factors to trigger an ultrasound scan and the examination misses some. In many European countries ALL babies are therefore offered an ultrasound as it is more accurate than just examining their hips or just scanning when risk factors are present..
How would I know if my baby had DDH that was missed?
The physical examination is not 100% accurate as this only detects hip instability at the time of the examination. This means that some babies might appear to be normal at the tests but develop problems later or that DDH has not been picked up at the initial examination. As routine hip examinations finish after the 6-8 week check, family members are best placed to identify a problem. Early diagnosis gives the best chance for effective treatment as the condition becomes more difficult to treat as child gets older and there is a risk of developing arthritis of the hip at a young age.
There are a number of signs of possible DDH and as the child is unlikely to feel pain even if displaying these signs, parents should watch for signs of DDH such as:
• Deep unequal creases in the buttocks or thighs
• When changing a nappy one leg does not seem to move outwards as fully as the other or both legs seem restricted
• The child drags a leg when crawling
• One leg looks longer than the other
• A limp (if one leg is affected) or a ‘waddle’ if both hips are affected
If you have any concerns you should contact your GP or Health Visitor.
Treatment for DDH
From birth to six months, babies with developmental dysplasia of the hip are usually fitted with a special fabric harness, the most common types being the Pavlik harness or the Van Rosen Splint. The type of harness will vary, depending the treating hospital. The harness keeps the baby’s hips and knees flexed upwards and outwards which encourages the hips to develop more normally. Studies have shown that the best time for this treatment is between the ages of 6 to 12 weeks. The harness needs to be worn for several weeks and in most cases this will correct the condition.
Some babies with an unstable hip in the first few weeks may stabilise themselves without treatment and may just require a follow up scan. Although we have outlined some possible problems, it is important to remember that the great majority of children with an unstable hip at birth grow and develop normally and do not develop early arthritis.
Where can I get more information about DDH?
The STEPS charity has additional information and useful leaflets and videos about DDH. https://www.stepsworldwide.org/conditions/hip-dysplasia-ddh/and have produced a useful guide which explains why a baby’s hips are checked at birth, what the tests are and what happens if a problem is found. It also tells you how to keep your child’s hips healthy – https://www.stepsworldwide.org/wp-content/uploads/2020/02/Baby-Hip-Health-website.pdf
What can I do to help my babies hips to develop normally?
Things that could hinder normal hip development are; tight swaddling or spending long periods of time in car seats. So anything that pulls the hips straight or restricts their natural movement should be avoided.