Developmental Dysplasia of the hips (DDH)

Have you as a parent ever wondered what the doctor is up to when he or she lies your baby on its back and makes little circles with the legs or flicks the little legs out to the side? This is actually a very important check to ensure that your baby’s hips are stable and your baby isn’t suffering from a condition known as Developmental Dysplasia of the hips (DDH). You may also have heard the condition referred to as “hip dysplasia”.

Unchecked this condition will lead to trouble in the teenage years starting with groin pain and then developing into more serious conditions such as osteoarthritis or a hip labral tear.

While babies are usually born with this condition there are things which caregivers can do that could cause or make the condition worse. The way a baby is carried, allowed to sleep or wrapped can cause strain on the hip joint especially if the legs are kept straight and stiff or left hanging. We will look at this in more detail later in the article.

 

But what is DDH?

Let’s begin with understanding how the hip joint works and then move onto DDH.

At the top of the thigh bone is a ball (femoral head). This fits into the socket part of the pelvic bone (acetabulum) and is able to move around in all directions giving movement to the legs and supporting the body for all sorts of activities like walking, crawling, climbing and running. The important thing is that the ball always needs to stay inside the socket.

In the case of DDH, the socket may be too shallow to cover the ball of the thighbone completely. This allows the thigh bone to slide in and out of the socket. In severe cases the ball comes completely out of the socket and dislocates. In minor cases there may just be minor looseness in one or both of the baby’s hip joints.

It is not hard to imagine that a child’s development will be affected by this condition because the little legs won’t be stable enough for baby to weight bare and this will affect physical development.

What causes DDH?

As with many conditions the exact cause of DDH isn’t known.

In utero:

What we do know is that while baby is in the womb, the hip joint consists of a very soft cartilage. The ball and socket need to fit tightly together so that they can mould one another. If this doesn’t happen then the socket won’t form fully around the ball and the socket becomes shallow.

If a baby has limited space in the womb the ball may move out of position and not have space to move back in, causing the shallowing of the socket. The limited space may be due to a large baby, twin pregnancy or a first baby where mommy’s womb is small.

DDH is also more common in:

  • Babies born breech. This means that the baby doesn’t turn to allow the head to engage. When this happens the baby often ends up with one or both legs extended in a partially straight position rather than folded in a foetal position. Unfortunately, this position can prevent a growing baby’s hip socket from developing properly.
  • Where there is a family history of DDH.
  • Baby girls. Girls are four times more likely than boys to have DDH.

After birth:

As mentioned in the introduction, DDH can also be caused or made worse in babies by the way the baby is carried, allowed to sleep or wrapped.

What signs may indicate that my baby has DDH?

After birth and at the first couple of developmental checks, the doctor will perform 2 tests. The first is called a Barlow test. This involves making little circles with the baby’s legs while in a frog like position. The doctor will be feeling for and listening out for any clicks. The second is the Ortolani test where the doctor will flick the little legs to ensure that the ball doesn’t come out of the socket. Both tests are completely painless but very important.

As parents you can also look out for certain signs such as:

  • The skin folds under your baby’s bottom or on the thighs not lining up.
  • One leg being shorter than the other
  • A difference in the way one leg or hip moves when compared to the other.
  • A popping or clicking sound in the hips
  • If there is a dislocation on one side of the body, that leg may turn outwards
  • Baby may appear to have a larger space between the legs than normal
  • Your child developing a limp once he or she starts walking.

How is DDH treated?

There are various treatment methods depending on the severity of the condition. If your health care provider is concerned about your baby’s hips then the baby will usually be referred to an orthopaedic surgeon for further assessment.

Depending on the findings and the age of your baby, there are various treatment options:

  1. Observation- If baby is under 3 months of age and the hips are relatively stable, then the doctor may opt to observe the baby. Since the soft cartilage slowly hardens and becomes hard bone there is a good chance that the joint will correct itself.
  2. Pavlik Harness-this is a soft harness and is used in babies under the age of 4 months. The baby will generally wear the harness for 24 hours a day for about 12 weeks. The harness holds the hips in the correct position while allowing the legs to move freely. Most babies respond very well to this treatment.

3.  Abduction Brace- If the Pavlik harness fails then an Abduction Brace, made from a lightweight material that supports         the hips and pelvis is used. This is generally worn for 8 to 12 weeks.

4. Surgical options- If both braces fail to stabilise the hips then the orthopaedic surgeon may need to perform surgery.            Surgery may also be required in older children as the cartilage would have turned to hard bone and surgery may be the      only way to position the bones correctly.

How can we help prevent our baby developing DDH?

If your baby develops this condition while still in the womb, there is nothing you can do to prevent it. After birth, however we need to take care with swaddling, carrying and sleeping positions.

    1. Swaddling- When wrapping your newborn you can wrap their arms and torso snugly but avoid wrapping baby’s legs in a straight position. This may interfere with the healthy development of the joint. Instead of being kept straight your baby’s legs should be able to fold up into a “frog position”. From the examples of the types of harnesses you can see what the “frog position” looks like. Your baby must be able to move the legs upwards and out to the side at all times.
    1. Carrying- Whether you are carrying your baby or wearing baby in a sling, the legs should always be out to the side in a “frog position”. The baby should be supported under its bottom. Try never to allow the legs to point straight downwards or lie together across your body.
    1. Sleeping position- Your baby may favour one side of the head for sleeping but having the head in the same position for extended periods of time will affect the position of the hips as well. Try turning your baby’s head to the other side regularly. This will also ensure that baby doesn’t develop a flattened area on one side of the head.

 Conclusion

Developmental Dysplasia of the Hips is a condition which generally responds very well to treatment. Depending on the age at which your baby gets treated, your baby will most likely start walking at the normal age. Children with untreated Developmental Dysplasia of the Hips often start walking late and typically have a limp. Parents and caregivers play a very big role in helping those little joints to develop so that the wonderful milestones like crawling, walking and running are achieved without complication. Allowing good movement of those little legs in the early stages of life is key to the gift of movement later on.

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