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DEVELOPMENTAL DYSPLASIA OF THE HIP - HIP DYSPLASIA IN CHILDREN

Dr. Mersad Alimoradi 19 Oct 2021
DEVELOPMENTAL DYSPLASIA OF THE HIP - HIP DYSPLASIA IN CHILDREN

Have you noticed that your child has one leg shorter than the other? Or have you noticed something odd in the way your child moves?

Those may be signs of Developmental Dysplasia of the Hip (DDH) or hip dysplasia, a condition affecting the development of your child’s hip joint. DDH initially doesn’t cause pain and often goes unnoticed.

But, if left unattended, your child may grow up with a limp, hip pain, and hip arthritis. The good news is, various diagnostic tools and therapeutic interventions can be used to effectively treat hip dysplasia in children of various ages.

We’ve put together a guide to help you notice the signs of hip dysplasia in your baby and how it can be treated. So, keep reading to learn more.

What Is Developmental Dysplasia Of The Hip?

Developmental dysplasia of the hip is a condition most often present at birth. DDH is a problem in the way your baby’s hip joint forms. The hip joint is a ball and socket joint; the ball of your thigh bone sits in the socket of your hip bone.

In DDH, the hip bone forms abnormally. Your child’s thigh bone sits loosely in the hip socket, making it easier to be dislocated.

DDH was first described in the 1900s by Dr. Marino Ortolani, a pediatrician, Dr. Thomas Geoffrey Barlow, an orthopedic surgeon, and Dr. Ricardo Galeazzi, an orthopedic clinic director.

Developmental dysplasia of the hip has a prevalence of one in 1,000 children based on Barlow’s research.

Developmental dysplasia of the hip is commonly seen in:

  • A first-born child, since the uterus is tight during first pregnancies increasing the risk for DDH.
  • Girls - they are four times more prone to hip dysplasia than boys.
  • A baby growing in a breech presentation or bottom down in the womb.
  • A baby with family or relatives with a history of hip dysplasia.

What Are The Symptoms Of Hip Dysplasia In Children?

Hip dysplasia in children doesn’t usually cause pain so your child may not show symptoms of hip pain. The symptoms of DDH are easy to miss unless you know what you're looking for.

Here are six questions to guide you. If you answer “yes” to most of these questions, chances are your child has DDH:

  1. Is the length of your child’s legs the same or symmetrical? In DDH, the affected leg looks shorter than the normal leg.
  2. Do your child’s upper thighs have uneven folds underneath? The affected leg has a bigger fold in the upper thigh compared to the normal leg.
  3. Are your child’s thighs aligned? The affected leg is turned outward in hip dysplasia so there is a wider space in between the legs.
  4. Does your child’s hip-pop or click when moved? The femur (thigh bone) does not lodge properly to the hip socket because of dislocation, which explains the popping or clicking sound.
  5. When your child moves, does one leg seem to move more than the other? The abnormal development of the hip joint affects the leg function. The affected leg can’t move properly compared to the normal leg.
  6. Was your child limping when he/she started to walk? Children limp when they begin walking since there is less movement or effort from the affected side.

When you notice any of these signs, it’s best to consult an orthopedist or a pediatrician to get a full evaluation for hip problems.

What Causes Hip Dysplasia In Children?

DDH is the most common orthopedic disorder in babies. Structural, genetic, environmental, and mechanical factors can lead to the development of hip dysplasia in babies.

Developmental Deformities

During the baby’s development, the bones do not form normally. Take femoral anteversion for example. In femoral anteversion, there is the inward rotation of the long thigh bone that worsens hip dysplasia in children.

Another developmental defect that leads to DDH is a dish-shaped acetabulum. It is typically a cup-shaped hip bone covering the head of your thigh bone. It allows the hip to latch on to the femur. A dish-shaped bone does the opposite and the improper fit also changes the alignment of the femur.

Genetics

Several studies reveal that children with DDH had a family history of the disorder. Several genes are linked to the development of the joint, namely OXD9, ASPN, HOXB9, TGF-Beta 1, PAPPA2, SKKI, and GDF5. If you have a family history of hip dysplasia, you may pass the condition to your child.

Breech Position

Babies in the breech position have extended knees inside the womb. This position of the hamstring or thigh muscle adds to the instability of their hip. This is usually common in first-born children since the uterus is still tight. As a result, there is more pressure on their hip joints and stretching in their ligaments, increasing their risk of DDH.

Swaddling

Swaddling is thought to provide comfort and reduce crying. However, improper swaddling may lead to hip dysplasia in babies. Normally, your baby’s legs are in a fetal position in the womb. The legs are bent up and across each other.

When you swaddle, there is a sudden extension of your baby’s legs. The stretching of their legs for long periods can loosen their joints and damage the soft cartilage in the hip socket. A study cited that DDH is high among Native American cultures because of swaddling.

Complications Of DDH

Untreated hip dysplasia may become worse and lead to further damage and pain. Developmental dysplasia of the hip should be diagnosed and treated as early as possible to prevent severe complications such as:

  • Dislocation: DDH puts your child at risk of dislocation because it damages the cartilage or connective tissue of the bone and joint over time. This condition results in the bone slipping out of place.
  • Hip labral tear: Not only does DDH dislocate a hip, but it can also tear the soft tissue covering the hip socket, leading to hip labral tear. A hip labral tear causes stiffness and pain in the hip.
  • Osteoarthritis: Osteoarthritis is a disorder wherein the protective cartilage on the ends of the bones are worn away. Over time, DDH can lead to early onset hip osteoarthritis, especially among females. 

This is because there is more contact pressure over a smaller surface of the socket. As it progresses, the smooth cartilage that helps the bones glide easily with joint movement are worn down.

  • Avascular Necrosis (AVN): AVN is a major complication of the femoral head. It usually occurs after treatment of hip dysplasia. AVN is a lack of adequate blood supply leading to bone tissue death. 

Symptoms of AVN are unnoticeable at first. As it worsens, your child will start to feel pain. The bone and joint may collapse and your child’s pain can escalate to the point where they find it difficult to move the affected side.

How Is Hip Dysplasia In Babies Diagnosed?

DDH is usually observed during a newborn screening, a series of tests performed on 1 to 2 days old infants before they leave the hospital. However, hip dysplasia in babies often goes unnoticed until the baby grows older.

If you observe signs of DDH in your child now, seek advice from your child’s healthcare provider. They will likely request diagnostic testing after thorough physical evaluation.

Clinical Tests For Hip Dysplasia

Certain physical examinations were designed specifically to diagnose hip dysplasia in babies up to 6 months old.

  1. Barlow's test: As your child lays on their back, your doctor gently moves the thigh inwards (adduction) to the midline and applies posterior pressure to the knee. Normally, there is no movement in this direction. A positive sign is when the hip pops out.
  2. Ortolani's test: This maneuver is the opposite of Barlow’s test. Your doctor gently bends the knees 90° and moves the thigh outwards (abduction) from the midline. Here, your doctor is trying to relocate the dislocated femoral head. Like the Barlow’s test, a clunk sound as the head slides back into place is a positive for DDH.
  3. Galeazzi's sign: Your child is placed in a supine position with their knees flexed at 90°. The feet stay flat on the table, with heels touching their buttocks. A positive sign of DDH is when one knee looks shorter than the other.

Imaging Tests

X-ray, Magnetic Resonance Imaging (MRI), and Ultrasound can provide a clear view of how your child’s hip joint has formed. These tests allow your doctors to evaluate the symmetry and appearance of the joint and detect any signs of developmental dysplasia.

What Are The Treatments For Developmental Dysplasia Of The Hip?

Subluxation or dislocation can be naturally corrected during the first few weeks of newborn infants. However, if the condition persists for over 6 weeks, your doctor may conduct a physical examination on your baby for DDH.

Your doctor will base the appropriate treatment on your child’s age and severity of the DDH. The goal of treatment is to keep the ball of the femur in the hip socket and prevent the early development of osteoarthritis.

Brace or Harness

A brace or harness is a conservative first-line treatment for children under 6 months. Studies show that it is the most effective treatment when started at 3 months old. About 5.7% of babies no longer needed further treatment.

The most common form of bracing is the Pavlik harness. It’s a shoulder harness that attaches to foot stirrups. The harness puts your baby’s legs in a position that allows the ball of their hip joint to stay firmly in the socket.

Splint or Spica Cast

A splint or cast is best for children over 6 months old. Your doctor uses a cast to set your child’s hip in the proper position for several months. One study reveals a hip spica cast was effective and safe in treating DDH in 83.7% of babies with DDH.

Surgery For Hip Dysplasia

Surgery is a last resort when all possible non-invasive procedures have been exhausted. Open surgery may be necessary in late diagnosed DDH. In open surgery, your surgeon makes an incision at your baby’s hip to view the bones and soft tissues.

In most cases, all your surgeon has to do is realign your child’s hip. However, they may need to shorten the thigh bone to properly fit the bone into the hip socket.

Your child will need a spica cast for another 3 months to hold their hip in place. According to research, the best age for hip dysplasia surgery is below 4 years old.

Outlook of Developmental Dysplasia of The Hip

Both non-surgical and surgical treatments aim to relieve your child’s pain and discomfort and prevent further complications.

Based on clinical studies, devices such as braces, harnesses, splints, and casts have been successful treatments for hip dysplasia in children of various ages. Your doctor can consider surgery when non-invasive treatments do not work.

Talk to your doctor about your child’s best treatment options. It may be a slow process, but the long-term results are usually excellent.

FAQs 

Can hip dysplasia in babies be prevented?

DDH cannot be prevented. The causes of hip dysplasia in babies are beyond our control. What you can do is use this article as a guide to help you notice any signs of DDH in your child.

Is developmental dysplasia of the hip a lifetime condition?

Hip dysplasia in children is a treatable condition. Your child can grow up normally with early diagnosis and treatment. Most children treated for DDH don’t develop hip problems later in adulthood.

Can imaging tests like x-ray harm my child?

Don’t worry, your child has little risk from exposure to x-rays. FDA standards for a hip x-ray for babies is 0.001 millisievert which is an insignificant dose that will not cause any harm to your child.

What are the risks of hip dysplasia treatments?

A potential complication of these treatments is a disruption to the hip joint’s blood flow, leading to avascular necrosis (AVN). Other risks include pressure sores, damaged nerves or femoral nerve palsy, and contracture or deformity.

Where do I seek medical advice for DDH?

You can talk to your family doctor, pediatrician, or maternal and child nurse. However, it’s best to consult a pediatric orthopedist specializing in children with dysplasia of the hip.

To search for the best Orthopedics Healthcare Providers in Croatia, Germany, India, Malaysia, Singapore, Spain, Thailand, Turkey, Ukraine, the UAE, UK and the USA, please use the Mya Care search engine.

About the Author:
Dr. Mersad is a medical doctor, author, and editor based in Germany. He's managed to publish several research papers early in his career. He is passionate about spreading medical knowledge. Thus, he spends a big portion of his time writing educational articles for everyone to learn.

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