Perthes disease usually occurs in children. It takes time, but most children recover fully.

What is Perthes disease?

Perthes disease is a problem with the blood supply to the top of the thighbone, or femur. The top of the femur is a ball, sometimes called the femoral head.

The femoral head fits into a socket in the pelvis to form the hip joint. It is called a ball and socket joint.

In Perthes disease, the femoral head becomes soft and goes out of shape. This causes pain and a limp.

Causes of Perthes disease

It is not clear why the blood supply to the femoral head is reduced.

Perthes disease usually affects children aged from 3 to 11 in one hip. In some cases, it affects both hips, and it sometimes runs in families.

Symptoms of Perthes disease

Symptoms of Perthes disease include:

• pain in the hip, knee or groin
• a slight limp that becomes worse over time
• limited movement.

Diagnosis of Perthes disease

If your child has pain in the hip, your doctor may suggest an x-ray to diagnose Perthes disease. If the x-ray doesn’t provide an answer, other more sensitive tests can include:

• MRI scan
• ultrasound
• bone scan.

Treatment of Perthes disease

If your child has Perthes disease, he or she will probably be referred to a specialist.

The bone will repair itself, as long as it is not too damaged. This takes time, usually between 1 and 5 years.

The aim of treatment is to avoid making it worse. This might include:

• avoiding activities with a high impact on the hip, such as running
• rest and use of a wheelchair or crutches
• a splint or a plaster
• special exercises.

A few children will need surgery.