When we think of hip dysplasia, what really comes to mind? An ageing golden retriever (it is often a side effect of certain dog breeds) or your overweight grandpa glued to his recliner with the TV remote in his hand. It’s likely you will assume that this is an old age-only condition, right? You’d never imagine that your newborn is at risk, nor would you know what to look for to gauge whether your child’s hips were healthy and normal.
It is important to recognise it, because although it isn’t a painful condition, it can make children limp, can make one leg shorter than the other, and can mean the hip develop painful arthritis at a relatively early age
Hip dysplasia might very well be one of the earliest and therefore more confronting health conditions a new parent has to deal with and is one of the most common paediatric orthopaedic conditions affecting children from newborn age, during childhood with effect even during adulthood and old age.
Also known as developmental dysplasia of the hip (DDH), the condition involves a problem with the development of the hip joint, and there are different types — from a shallow hip socket to a complete dislocation. “It is important to recognise it, because although it isn’t a painful condition, it can make children limp, can make one leg shorter than the other, and can mean the hip develop painful arthritis at a relatively early age,” says Dr Gavin Malcolm Spence, Consultant Paediatric Orthopaedic Surgeon at Burjeel Hospital for Advanced Surgery.
In all cases of DDH, the socket (acetabulum) is shallow, meaning that the ball of the thigh bone (femur) cannot firmly fit into the socket. The ligaments and capsule that help to hold the joint in place are stretched.
“The degree of hip looseness, or instability, varies among children with DDH,” says Dr Ahmed Doheim, Specialist — Paediatric Orthopaedic, Medcare Orthopaedics and Spine Hospital. “The spectrum of the condition can be dislocated — in the most severe cases of DDH, the head of the femur is completely out of the socket. Dislocatable — in these cases, the head of the femur lies within the acetabulum, but can easily be pushed out of the socket during a physical examination. Subluxatable — in mild cases of DDH, the head of the femur is simply loose in the socket. During a physical examination, the bone can be moved within the socket, but it will not dislocate.”
Signs and symptoms
All newborns undergo physical examination immediately after birth and at six to eight weeks to diagnose DDH early. But sometimes hip problems can develop after these checks.
The spectrum of the condition can be dislocated — in the most severe cases of DDH, the head of the femur is completely out of the socket.
“It’s important to contact your doctor if you notice your child has developed symptoms such as restricted movement in one leg when you change their nappy or one leg dragging behind the other when they crawl,” says Dr Arun Gopalakrishnan, Specialist Orthopaedic Surgeon, Aster Hospital, Qusais. “Also observe if one leg appears longer than the other, or look for uneven skin folds in the buttocks or thighs or a limp.”
Hip dysplasia alone does not cause any symptoms at first, explains Dr Mustafa Karoud, Chief of Orthopaedic and Joint Replacement Department, American Hospital Dubai. However, if it is not recognised in time, damage to the acetabulum and head (such as hip arthrosis in later life) or hip dislocation can occur.
“With hip dislocation, the femoral head pops out of the socket. In this case, the baby can only partially move the legs away from the body. The leg on the affected side appears shorter than the other. The shortening of the legs and the asymmetry of the folds can, however, be absent in the case of bilateral hip dislocation. Older children may experience a hollow back or “waddle walk”. If such signs appear, parents with their child should immediately see a paediatrician or orthopaedic surgeon.”
Who is affected?
DDH is more common in girls, in first born children, in babies who are born feet first (breech position) and it can run in families. “That said, any child can get it, so all need to be checked for it,” says Dr Spence.
Using hip-healthy swaddling techniques can reduce this risk. Make sure your baby is able to move their hips and knees freely to kick.
While there are no known causes of hip dysplasia, there are risk factors such as multiple pregnancy causing narrowing and tightness of the uterus during pregnancy; or muscular or neurological disorders such as spina bifida (open back). “Hormonal factors like progesterone, which loosens the pelvis during the birth process, is also believed to cause loosening of the hip joint capsule in female babies,” says Dr Karoud.
Usually it is diagnosed soon after birth, when a specialist tests for clicky hips using a particular examination technique. “If they are concerned about the hips, they usually confirm their suspicions with an ultrasound scan,” says Dr Spence. “After about six months of age, X-rays are the best test to diagnose it.”
The gold standard method is the clinical screening at birth and at subsequent paediatrician clinical examination. The Ortolani test and Barlow test are mandatory.
“During the physical exam, signs such as gluteal fold asymmetry (unevenly formed skin folds at the base of the thigh) and spreading inhibition (a leg cannot be spread as far as usual) may indicate hip dysplasia,” says Dr Karoud.
With consistent treatment in the first weeks and months of life, the hip joints develop normally in over 90 per cent of the children affected.
Can improper swaddling cause hip dislocation? “This isn’t one of the recognised risk factors, although in societies where children are swaddled from birth with their hips and knees straight (like the Inuit people) there is a high incidence of hip dysplasia,” says Dr Spence. “This may be due to genetic factors rather than due to the swaddling. It is probably best to avoid restricting babies from flexing their hips for long periods of time.”
A baby’s hips are naturally more flexible for a short period after birth, but if your baby spends a lot of time tightly wrapped with their legs straight and pressed together, there’s a risk this may affect their hip development. “Using hip-healthy swaddling techniques can reduce this risk,” says Dr Gopalakrishnan. “Make sure your baby is able to move their hips and knees freely to kick.”
How is it treated?
Babies diagnosed with DDH early in life are usually treated with a soft splint called a Pavlik harness. The splint secures the baby’s hips in a stable position and allows them to develop normally.
“The harness needs to be worn constantly for several weeks and should not be removed by anyone except a health professional,” says Dr Gopalakrishnan. “The harness may be adjusted during follow-up appointments. Your hospital will provide detailed instructions on how to look after your baby while they’re wearing a Pavlik harness.”
In dislocated hips in less than six-month-old babies, a trial of reduction of the hip under anaesthesia can be done followed by a cast to immobilise the hip in the correct position. “If the age is above six months, then a surgery would be recommended to relocate the hip in its socket, and it is usually combined with bone cuts in the thigh bone or hip bone to improve the joint containment and depth of the socket,” says Dr Doheim. “Dysplasia without dislocation in older children and adolescents can be treated with surgery to reorient the hip socket and improve its coverage.”
Is it worthwhile to routinely screen children for DDH? Different countries have different policies for hips screening. Some rely only on clinically testing the babies immediately after birth, some will have obligatory ultrasound examination for all neonates.
“What is advised is that all babies should be at least clinically tested immediately within minutes of birth by the paediatrician in charge,” says Dr Doheim. “Confirmed or doubtful cases should then have an ultrasound to confirm the diagnosis then to be referred to a paediatric orthopaedic doctor to initiate the appropriate treatment.”
Dr Karoud agrees that sooner hip dysplasia is treated, the faster it can be remedied and the greater the chances of recovery. “With consistent treatment in the first weeks and months of life, the hip joints develop normally in over 90 per cent of the children affected,” he says. “If, on the other hand, hip dysplasia is recognised late, surgery can usually not be avoided. There is also a risk of hip dislocation and premature wear of the hip joint — this can result in osteoarthritis even in young adulthood.”
The prognosis of treated cases depends mainly on the severity of the condition, age at which the treatment was done, the earlier being better, and how good and successful the treatment is in restoring the anatomy to its original state. “Most of the well treated hips before the age of two years will do well and will have a good functional painless hip,” says Dr Doheim.
Dr Karoud explains, “In hip dysplasia, physiotherapy helps to counter limping. Above all, muscles are trained that stabilise the hip.”