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Ask the Expert: What is Hip Dysplasia?

hip dysplasia diagram

Dr. Ernest Sink, Orthopedic Surgeon, answers questions on hip dysplasia.

Q1. What is hip dysplasia?

The hip is made up of the acetabulum (hip socket) and the femoral head to make a ball and socket joint. Hip dysplasia is a condition that occurs when the socket (acetabulum) doesn’t adequately support the ball (femoral head). This could be because the socket is not large enough or it is not oriented over the ball. Hip dysplasia ranges from a partial or full hip dislocation in babies to adolescents or young adults with no dislocation but hip pain and possible wear and tear of the cartilage and the surrounding structure of the hip over time. Hip dysplasia can be measured on spectrum – there are different levels of severity. In the majority of cases, it is not detectable at birth (except when the hip is dislocated or detected with selective screening) but can become painful when one ages.

Q2. What causes hip dysplasia?

The causes are multi-factorial: both genetics and environment can cause hip dysplasia. Environmental causes include position of legs in uterine (breach position). There is also new research on the negative effects of swaddling on babies’ hips.

Q3. How is hip dysplasia treated?

It depends on the patients’ age. For babies, the goal is to find it early and treat them with bracing (a Pavlik harness) or close observation to make sure the hip normalizes. When the Pavlik harness is needed, this positions the legs so that the hips would relocate and the dysplasia will improve over a few months. The goal is that the hip socket would then develop normally. In the older child where a Pavlik harness did not work or they are too old (6 months of age), surgical reduction is usually required. The surgery would put the ball back into the socket. In the adolescent or adult with dysplasia, a successful surgery is periacetabular osteotomy (PAO) which reorients the hip cartilage so it sits in a better position.

Q4. Who is at greater risk for hip dysplasia?

Hip dysplasia is more common in females – it is the number one cause of hip replacements in females under 50. Approximately 1-3% of newborns have hip dysplasia however it may be undetectable. Many times it does improve on its own. Other times, the symptoms do not appear until the patient is a teenager or young adult.

Q5. What is osteotomy?

Osteotomy is cutting of the bone. This surgical procedure involves a series of bone cuts to free the socket from the pelvis and reposition it so the cartilage can better support the femoral head. This is not a common orthopedic procedure; Hospital for Special Surgery is one of the few centers that specialize in it. While it is a complex technical surgery, it is safe and successful. This procedure is able to successfully solve the hip problem (minimizing pain) and also works to delay or prevent hip replacement.

Q6. Who is a candidate for osteotomy?

Osteotomy is performed on skeletally mature patients (adults) with hip dysplasia.

Dr. Ernest Sink, HSS pediatric orthopedic surgeonDr. Ernest Sink is an orthopedic surgeon and Co-Director of Hospital for Special Surgery’s Center for Hip Preservation. He specializes in the treatment of hip disorders in infants, adolescents and young adults, including periacetabular osteotomies (PAO) and surgical hip dislocations.

Topics: Orthopedics
The information provided in this blog by HSS and our affiliated physicians is for general informational and educational purposes, and should not be considered medical advice for any individual problem you may have. This information is not a substitute for the professional judgment of a qualified health care provider who is familiar with the unique facts about your condition and medical history. You should always consult your health care provider prior to starting any new treatment, or terminating or changing any ongoing treatment. Every post on this blog is the opinion of the author and may not reflect the official position of HSS. Please contact us if we can be helpful in answering any questions or to arrange for a visit or consult.