Developmental Dysplasia of the Hip (DDH)
What is Developmental Dysplasia of the Hip (DDH)?
Developmental Dysplasia of the Hip is a condition which affects the way the hip joint develops and commonly present at the time of birth. It was formally known as congenital dislocation of the hip (CDH). Most children treated early will develop into a healthy and active child with no hip problems. Our Private Paediatric Orthopaedic Consultant has several years of experience in managing DDH presenting at different ages.
Infant Hip Anatomy
The hip joint is a ball and socket joint. In DDH, the ball part of the top of the thigh bone (femoral head) does not sit properly into the cup part of the pelvis (acetabulum). The severity of hip dysplasia varies from having a slightly shallow cup, to a dislocated hip where the ball is not in contact with the cup. If the acetabulum is too shallow, the ball of the femoral head may move in and out and this is called subluxation. In order for the hip joint to develop normally, the ball must be in the socket.
What Causes DDH in Children?
Around 1-2 per 1000 babies born in the UK are affected. DDH can occur in any baby but certain risk factors can increase the likelihood of it happening. There are several risk factors but the main ones are:
1. Breech position during the pregnancy, particularly the 3rd Trimester
2. A family history of hip dysplasia e.g. parent or sibling
3. First Born Child
4. Girls
What are the symptoms of Hip Dysplasia in children?
Signs and symptoms of DDH can vary depending on the age of the child. The majority of cases are detected during routine baby checks which is part of a national screening programme, the Newborn Infant Physical Examination (NIPE). If the hip is subluxated or dislocated (out of the cup), the affected leg may appear shorter than the unaffected leg. If both hips are dislocated, this may not be the case. The baby’s hips are moved into certain positions and the stability of the hip joint is checked using the Ortolani and Barlow Tests. Restricted movement of the hip, particularly with the hip bent upwards and outwards is also a sign that the hip joint may be affected. This restricted movement may also be apparent when changing nappies. If the baby’s examination is abnormal, they will be referred for further investigation in the form of an ultrasound scan.
The baby may have a normal hip examination but if they meet certain criteria such as risk factors for DDH, they may be referred for an ultrasound scan as well.
How does DDH affect babies crawling?
DDH will not stop a baby’s ability to crawl as the hip will be able to move and the muscles around the hip will be able to work almost normally. However, they may drag the leg when crawling.
How does DDH affect toddlers walking?
Again, DDH does not affect the ability for a toddler to walk but there may be subtle differences observed in walking patterns. One sign may be a painless limp or toe walking due to a shorter leg. It is important that if any of these signs are apparent, a doctor should be consulted.
How is Developmental Dysplasia of the Hip Diagnosed?
If a baby shows possible signs of DDH or has risk factors for DDH, an ultrasound will be arranged. This is a painless test using the same technology as for antenatal baby scans. For infants and older children, an X-ray of the hips may be performed. These investigations will identify the presence of shallow sockets (dysplasia) or whether the hip is subluxated or dislocated (out of the socket).
What are the treatment options for DDH in children?
There are a range of treatment options for DDH. Which option is recommended is dependent on the age of the child.
Treatment for Hip Dysplasia in Babies
Babies diagnosed with DDH in the first few months of life can be treated in a special fabric harness called a Pavlik Harness which holds the legs flexed up and outwards. It is a dynamic splint meaning the baby’s legs will be allowed to move to a small degree in a protected arc of movement. The ideal time for fitting the harness has been shown to be around 6-12 weeks of age. This will be kept on for several weeks and regular ultrasound scans of the hip will be performed to check that the hip is in an optimal position. Once the hip shows signs of improvement, the harness will be removed and in most cases, this is 3 months after the start of treatment. The baby will undergo regular follow up for several years to ensure the hip is developing normally.
Surgical Options for Older Children with DDH
6month-2years. A ‘closed reduction’ procedure may be performed under general anaesthesia. The surgeon relocates the hip joint by moving the leg into a bent up and outwards position. Release of tight tendons (psoas and adductor longus) may be required to help stabilise the hip. A body plaster cast called a hip spica is then applied for several months. If this procedure is not possible, an open reduction may be performed and also reshaping of the ball and socket joint. This involves a more complex procedure which the surgeon will explain if required. This is commonly followed by a period in a hip spica.
Older than 2 years. Children who present later will likely require open surgery to realign the hip in the form of open reduction and reshaping of the ball and socket joint (femoral and pelvic osteotomy) followed by immobilisation in a hip spica.
What is the surgery recovery time for a child with hip dysplasia?
Following closed or open reduction, children are placed in a hip spica (body plaster cast) for several months. The length of time will be dependent on the procedure and the cast may be changed during this time period if the child outgrows the plaster cast.
Once the cast is removed, it will take a few months before the child regains full movement of the hip. This will vary according to the procedure and also the length of time in plaster. Regular follow-up appointments for clinical examination and X-rays will be scheduled until the surgeon is happy the hip has developed and this is likely to be until growth is complete.
What happens if DDH is not treated in children?
If DDH is left untreated, secondary complications from an abnormal hip joint may present in early adulthood. Damage can occur to the femoral head which can be painful and invariably lead to osteoarthritis of the hips (wear and tear arthritis). This may produce reduced mobility and leg length differences. If this happens, the hip joint may need to be replaced with a total hip replacement.
Why Choose Hertfordshire and London Children’s Orthopaedics?
It is important that you see a qualified surgeon if you are worried about your child having hip dysplasia. At Hertfordshire and London Children’s Orthopaedics, our consultant has extensive experience in providing care to children of all ages who have DDH. A consultation should be performed in order to assess your child and discuss whether further investigations are required. Please book an appointment if you are worried that your child may have signs of DDH.
Helpful Resources:
STEPS Charity
AUTHOR:
Stephen Ng Man Sun is a Paediatric Orthopaedic Consultant at Chelsea and Westminster Hospital, London. He has been a consultant since 2019 and is a fellowship trained Paediatric Orthopaedic Surgeon. You can read more about Mr Ng Man Sun on our About Page or connect with him in LinkedIn / Twitter.