Developmental Dysplasia of the hip (DDH)
DDH occurs in 3-5 children per 1000 children born. We now test for this condition as part of the newborn screening process so many cases are being picked up early. If the condition isn’t found in the newborn screening test, it may present as a limp in a toddler or as activity related hip pain in a child or adolescent. The problem with DDH is that it can lead to dislocation of the hip. Dysplasia without dislocation usually has no clinical signs and remains asymptomatic until adolescence or adulthood.
DDH is diagnosed using a combination of clinical examination and investigations. Ultrasound is the investigation used up to 6 months of age and x-rays are used for all children older than 6 months.
The hip joint has excellent remodeling potential in the young person but after school age the potential for improvement decreases. This is why it is important to diagnose the condition as early as possible. The goal of treatment is to make sure the hip joint is maintained in correct alignment to allow for remodeling of the joint. This is achieved with the use of an abduction splint (eg Pavlick harness) in the young infant up to 10 months old to promote normal development of a dysplastic hip. For older infants, reduction under anaesthetic followed by a cast for 3-4 months is needed to maintain alignment. Once the child is older than 18 months, surgical reduction becomes less successful and other procedures are often needed. After 8 – 10 years of age surgical outcomes are usually worse than doing nothing. The child may function well for years with the condition but will often progress to functional disability and pain at some stage. Eventually this may lead to the development of osteoarthritis and the need for a total hip replacement as a young adult.
Perthes disease is one of a group of conditions known as osteochondroses that affect the growing skeleton and articular cartilage. The exact cause is not known but proposed mechanisms include bone stress from repetitive loading, local ischaemia and genetic disposition. It is an idiopathic osteonecrosis of the hip that leads to bone necrosis due to lack of blood supply. It occurs in children between the age of 4 and 10 but is most common in boys aged 5 to 7. Boys are 3 – 4 times more likely to get Perthes disease than girls.
Perthes disease presents as either hip pain or a limp that develops without an obvious cause. The pain is related to activity and can sometimes present only as thigh or knee pain. It is diagnosed using a combination of clinical examination and imaging, although initial xrays are often normal so a high index of suspicion is needed to detect it early. It is common to have reduced range of motion in the affected hip. It usually only affects one hip but can affect both in 10 – 20% of children.
The condition is managed initially with rest from aggravating activities and exercises to maintain range of motion of the joint. Children under 6 usually do well with analgesia and avoidance of jumping and running but older children may have more complications and some may need surgical management. The femoral head may take 2 to 3 years to recover completely and an older child may need to be non-weight bearing initially. The child should not participate in any running or jumping sports while the bone is healing. The bone eventually gets revascularised (the blood flow returns) and the child can return to sport when they have no symptoms and the x-rays show some improvement.
Slipped Upper Femoral Epiphysis (SUFE)
The femoral epiphysis is the growth plate of the femoral head which is the ball part of the ball and socket joint of the hip. In some adolescents, the shearing forces applied to the femoral head exceed the strength of the growth plate. This leads to the long part of the bone slipping forward along the line of the growth plate away from the ball part, which stays in the joint. The condition occurs in one adolescent in every 1000 – 10,000 in their age group. The biggest risk factors are obesity and endocrine disorders (hypothyroidism or growth hormone deficiency) but the condition can occur in athletic children with no risk factors.
SUFE usually presents as hip pain but it can present as thigh or knee pain without any hip pain at all. The pain is worse with activity and relieved by rest but it can take up to an hour of rest for it to settle. The typical presentation is an overweight, prepubescent (12 – 15 year old) child at the time of their peak growth, around 12 years old in girls and 13-14 years old in boys. 20 – 40% of cases present with both hips affected on initial presentation and in those who only have one side affected, the other side will be affected in the future in 30 – 60% of cases within 18 months.
Diagnosis is made with a combination of clinical examination and imaging (x-ray). There are acute and chronic types and sometimes a combination of both. Acute slips present with an effusion (swelling) as well as severe pain and disability for no longer than 3 weeks. Chronic types might have less severe pain but show remodeling of the growth plate on x-ray.
The condition needs to be treated immediately to prevent further complications. Anyone with a suspected SUFE should be made non-weight-bearing on crutches (or a wheel chair) until the diagnosis is confirmed and then urgent referral to a surgeon is required for operative management. Operative management aims to stabilise the growth plate with a screw and prevent further slippage. The child is only allowed to partial weight bear for 6-8 weeks after surgery with crutches before making a gradual return to activity and sport. Delays in diagnosis can lead to a worse outcome for the child so it is important to seek treatment early.
If your child has hip pain that doesn’t settle after a few days of rest, a consultation at Shire Sports Medicine can be beneficial to get an accurate diagnosis, to help guide management and to ensure the prevention of further complications.