What is Hip Dysplasia and does my baby have it?

When a person becomes a new parent, there is often a large amount of fears about everything possible that can happen to their baby: will they walk at 1 year, will they be allergic to foods, will they sleep through the night, the list never ends. One fear that many prospective and current parents come across is hip dysplasia. Reading the term by itself can conjure up all sorts of images, but when you understand what it is and what causes it, you will find that there is much less to fear about it.

In all humans, the hip is known as a “ball and socket” joint where the “ball” of the femur (leg bone) fits into the “socket” of the acetabulum (pelvis). It is held together by the surrounding ligaments and joint capsule, and is further supported by the surrounding muscles.

Hip dysplasia is a broad term for hip instability, dislocation, or shallowness of the hip joint socket in an infant, child, or adult. Instability and dislocation are found more often in infants, whereas shallowness is found during adolescence or adulthood.¹ The infant/child type can be referred to as Developmental Dysplasia of the Hip or DDH; other than the instability or dislocation, the joint is normal.

DDH can have a wide range of severity. If the ligaments are loose, the hip can subluxate (or shift) the ball from the socket. In other instances, the ball will slightly or completely dislocate from the socket. 10% of infants are born with hip instability (from mild looseness to complete dislocation), and 1 out of every 100 infants is treated for hip dysplasia.

What causes DDH? It is unknown as to what predisposes one infant from having DDH while another will not. The hip socket is at its most shallow at birth, which makes it less congruent or less of a “fit” for the ball of the femur. Fetuses grow so much during pregnancy that by the third trimester their hip movement is limited, and having a shallow socket can help with passing through the birth canal. Hip sockets do become rapidly deeper during the first year of life, and continue to deepen during adolescence (if they don’t, it can lead to hip dysplasia later in life).

Here are factors that can increase your infant’s risk for DDH¹:

• DDH is more likely when there is a family history
  • 6% risk if a previous child had it
  • 12% risk if a parent had it
  • 36% risk if a parent and child had it
• DDH is common in firstborn children: 60% of cases
• Breech womb position https://www.shutterstock.com/image-vector/different-baby-positions-during-pregnancy-1391042585
• Babies with a fixed foot deformity or stiffness in the neck (torticollis) → due to limited space in the womb
• Birth hormones from the mother: used to increase the ligament laxity for the baby to pass through → some infants are more sensitive than others, and female infants are 4-5x more likely to be diagnosed with hip dysplasia than male infants.
• Bones of infant’s hip are softer than an adult hip
• Infant positioning: placing an infant with their hips extended have a higher rate than other children; this can be a particular problem with incorrect or tight swaddling and infant carriers that are incorrectly fitted

You might be wondering how you can tell if your infant has hip dysplasia. Here are common signs in infants and a sign for infants that have begun walking²:

• Hip clicking or popping with movement of the hip
• Difficulty diapering: legs may not fully spread and/or baby cries at every diaper change when you move their hips

• Asymmetrical gluteal folds: if the folds of your child’s buttocks do not line up, this can be a sign of DDH; watch for these asymmetric folds on the back of the legs too!
• Leg length difference: one leg is much longer than the other
• Walking infants: noticeable limp, can appear painless but is very exaggerated

You notice one of these signs with your child, where do you go from here?

• Visit your local pediatric physical therapist. They are trained in examination techniques and how to spot skeletal alignment asymmetries to help address your concerns with your infant’s development, and can create the best plan for whether or not your child has DDH.
  • If you visit a pediatric PT for torticollis in your infant, make sure they check for hip dysplasia!
• Visit your pediatrician and discuss your concerns. The doctor will order an Ultrasound (under 6 months) or X-ray (over 6 months) to determine the alignment of the femur in the pelvis.

Oh no, my child has DDH! What do I do now?

• Conservative (non-surgical) treatment options²:
  • Observation: infants under 3 months will be monitored by their pediatrician to see if it will begin to resolve
  • https://www.shutterstock.com/image-photo/baby-wearing-harness-that-corrects-hip-1999938161

Pavlik Harness: used on infants 4 months or younger to hold their hip in place. Typically worn all day and night with up to 1 hour total of no wearing per day to allow for diaper changes, bathing, pictures, etc. This can take 2-3 months for children to improve from this harness. An abduction brace (less straps than a Pavlik) may be used afterwards if the hip is still partially dislocated.

• Surgical Treatment Options:
  • Closed Reduction: typically performed if the Pavlik harness fails, a surgeon will use anesthesia and perform an arthrogram to set the ball back into the socket. Once in place, a spica cast will be used to hip the hips in place
  • Open reduction: when all else fails, an incision is used to view the hip and reposition it in the infant to prevent dislocation. A spica cast will need to be worn while it heals.

• Follow up: After wearing a Pavlik Harness or receiving surgery, your child may have muscle weakness, difficulty sitting or crawling, and/or may be falling behind on their developmental milestones. Visit a pediatric physical therapist or occupational therapist, who will create an individualized plan to address your child’s needs and your concerns.

If you would like more information on hip dysplasia, including resources and brochures to help yourself, your family, and your healthcare workers, visit the website of the International Hip Dysplasia Institute. https://hipdysplasia.org/

Follow this link to part 2 of this post, where we discuss different baby carrier and baby wearing options to help prevent hip dysplasia!

References:

1. Home – International Hip Dysplasia Institute
2. Hip Dysplasia | Boston Children’s Hospital (childrenshospital.org)
3. Effgen SK. Meeting the Physical Therapy Needs of Children. F.A. Davis Co; 2013.