The hip is a ball and socket joint that connects the thigh bone (femur) to the pelvis (acetabulum). The hip joint is the largest weight bearing joint in the body. The hip joint is surrounded by strong ligaments and muscles.
During fetal development, malformation of the hip joint results in the femur being loose in the acetabulum. In hip dysplasia, the acetabulum is shallow and the femur does not fit securely into the socket. This can range from slight underdevelopment of the socket through to frank dislocation of the hip joint.
It is important to know that this is not a painful condition for your baby and that treatment aimed at helping them develop a normal hip joint that isn’t prone to arthritis at a young age.
The cause of hip dysplasia is not fully understood. Common risk factors for developing hip dysplasia include:
- Family history of hip dysplasia
- Babies born in breech position
- More common in girls than boys
- More common in first born children
- Oligohydraminos (low levels of amniotic fluid)
The common symptoms of a baby with hip dysplasia include:
- Legs of different lengths
- Less mobility or flexibility on one side
- Limping, toe walking or waddling
- Uneven skin folds on the thigh
It is important to understand that your baby will not be in any pain due to hip dysplasia, even if the hip is dislocated, but untreated this condition will lead to arthritis at a far younger age than normal.
Because symptoms are not always present, newborns are generally assessed for hip flexibility and movement. Babies demonstrating, or at high risk of, hip dysplasia should be screened with a neonatal hip ultrasound which can be done at the time of your appointment with your surgeon. For dysplasia that has not been detected in infancy, older children may be referred for an x-ray of the hip joint.
Early diagnosis of hip dysplasia can lead to an easier and a more successful treatment which is why screening is essential to diagnose the disorder in infancy. Babies with hip dysplasia will often require a hip brace to hold the femur into the acetabulum. This will encourage the ligaments to tighten to hold the femur in place. The type of brace and the length of time wearing the brace depend on the extent of the dysplasia. Bracing the hips and legs results in a high rate of successful treatment and its associated with very low rates of significant complications.
Occasionally, where the hip has dislocated and cannot be manipulated back into place, surgery will be required to put the femur back into the acetabulum. This would then be followed by a period of time in cast and then brace treatment. This treatment is uncommon and would be discussed at length with you by your surgeon.
Finding reliable and easy to understand information about hip dysplasia can be hard. There is a lot of information available to parents on the internet although not all of it is of a high quality or easy to understand.
A few good references are:
- www.hipdysplasia.org – this is the website of the International Hip Dysplasia Institute, the peak body in research and education on hip dysplasia and covers diagnosis and treatment options from infancy through to adulthood
- www.healthyhipsaustralia.com.au – this website is a more personal perspective of the treatment of hip dysplasia by a family who have decided to document their journey and help demystify the process for other families in the same position
It is suggested you speak to your surgeon about any treatment options or questions you have at your appointment.