What is hip dysplasia?

Hip dysplasia is a condition that occurs where the ball and socket joint of the hip has not developed properly.  In hip dysplasia, the ‘socket’ part of the joint (the acetabulum) does not fully cover the ‘ball’ (the femoral head).

What causes hip dysplasia?

Hip dysplasia can occur as a result of a baby’s hips not developing properly in utero (developmental dysplasia of the hip, abbreviated to DDH), or it can be present after the hip is affected by another condition (such as Perthe’s disease, cerebral palsy or Charcot-Marie-Tooth).  

 The most common cause of developmental dysplasia of the hip (DDH) is the baby being cramped inside the uterus during pregnancy. As such, anything that affects the space available for the baby can cause DDH. Risk factors for DDH include the baby being first born, female, breech presentation, family history of DDH and oligohydramnios (low fluid levels in the uterus).

How is hip dysplasia treated?

 Hip dysplasia that is picked up in babies can often be treated non-surgically using a Pavlik Harness or Rhino brace. The amount of time in the brace will depend on the severity of the hip dysplasia and response to treatment.

 Once patients have reached adolescence there is no further remodelling potential of their hip, and residual hip dysplasia can only be treated with surgery. The best surgical option for this is a periacetabular osteotomy (PAO), which rotates the hip socket around to cover the femoral head.

What are the symptoms of hip dysplasia in adolescents and young adults?

All patients with residual or untreated hip dysplasia will eventually develop symptoms. The early symptoms are weakness around the hip muscles and pain during exercise. This will eventually progress to localised pain in the groin and can be associated with clicking or catching. This is a result of the labrum being damaged or torn as it is overworked to keep the hip in the socket. Once this hip socket becomes inflamed patients may start to develop stiffness in the hip.

 What is the consequence of not treating hip dysplasia?

Hip dysplasia will eventually progress into arthritis, which can only be treated with a total hip replacement. This occurs due to edge loading (i.e. uneven pressure) of the femoral head against the corner of the acetabulum (hip socket). It is difficult to predict exactly when the hip will develop arthritis. It will typically occur between the age of 30 and 40 depending on the severity of the hip dysplasia.

What is a periacetabular osteotomy?

A periacetabular osteotomy is a surgical procedure used to correct hip dysplasia in adolescents and young adults. It is typically performed on patients between the age 12 and 35. The surgery involves making an incision along the groin crease and then a series of bone cuts around the pelvis to free up the hip socket. The hip socket is then rotated to correct the underlying hip dysplasia and then fixed in place with screws.

What are the benefits of a periacetabular osteotomy?

A periacetabular osteotomy (PAO) will greatly improve the pain and function of a person with hip dysplasia. It will allow patients to return to high levels of sport and function. A hip that has undergone a PAO is still at risk of overuse, and as such high impact sports such as long distance running are generally discouraged to prolong the lifetime of the hip. A PAO will fix the uneven pressure on the hip joint involved with hip dysplasia and prevent or delay the progression to osteoarthritis. Studies show that when performed on the right patients at the right time, a PAO can delay the need for a hip replacement in 80% of patients for 20-30 years.

What are the surgical risks of a PAO?

All surgery involves risks, which are to be balanced against the potential benefits of the operation.  A PAO is a major surgical procedure, and as with any surgical procedure has risks both during and after the surgery.

Generally, the major risks of a PAO are:

• Infection

• Thigh numbness

• Deep vein thrombosis (DVT)

• Bleeding requiring a blood transfusion.

  • Dr Spelman uses a Cell Saver device that allows the patient’s own blood to be reinfused during the procedure, reducing the need for blood transfusion.

• Damage to nerves or blood vessels.

  • There is particular risk to the sciatic nerve (the nerve that control the movements of the foot), especially in patients that have scarring around the hip from previous surgery

• Non-union of the osteotomy (failure of the bones to heal)

• Progression to hip osteoarthritis over time

• Incomplete resolution of pain

There may be other risks that are important in your individual case.  It is important that you discuss any concerns you may have with Dr Spelman. 

What is the rehab following a PAO?

After undergoing a PAO, patients will be in hospital for approximately 4-5 days. Patients can get out of bed with the aid of a physiotherapist the day following the surgery. A urinary catheter will be inserted at the start of the surgery and removed day 2. Patients generally require pain relief for 1-2 weeks after the surgery.

Patients will require crutches for 3 months, with the first 6 weeks being touch weight bearing. The wound is checked at 2 weeks, and X-rays are taken at 6 weeks and 12 weeks post operatively. Usually around 6 months post-surgery the bone has healed and patients are able to return to normal activities. The screws will be removed as a day procedure approximately 6-12 months after the initial surgery through a small incision.

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