PERTHES DISEASE

What is it?

Perthes' Disease is the name applied to a condition which affects the upper end, or head, of the thigh bone, where it enters into the formation of the hip joint. In this condition the growing part of the head goes through a series of changes, in which it softens, may become flattened, and then gradually re-forms.

The changes of the disease are due to the fact that the growing end (epiphysis) of the thigh bone (femur), has its blood supply cut off. This results in the softening of part or all of the bony 'nucleus' of the epiphysis. The smooth cartilage ('gristle') covering this bone remains unchanged as it is feed by the joint fluid, so you don't have to worry about the shape of the bone in x-rays.

Who gets it?

The cause of the interruption of blood supply is not known. The condition usually develops between the ages of about 4 and 10 years, when the stage of development of the epiphysis renders it especially liable to such interruption. It occurs much more commonly in boys than in girls.

What are the symptoms?

When the process develops there is often a first pain in hip or knee, and some muscle spasm associated with limping.

What tests will the Doctor want to do?

Early diagnosis greatly improves the rate of recovery. Delayed treatment or diagnosis after the age of 8 may affect the outlook. Consult the doctor immediately the condition is suspected, or if the child limps for more than 48 hours. An x-ray must be taken; Perthes' cannot be diagnosed by a blood test.

The affected part of the bone looks denser in the x-rays. Over a period of time (measured in months), this bone is gradually and irregularly absorbed in the body, giving rise to the fragmented or broken-up appearance in the x-ray.

What is the treatment?

Many patients with Perthes' Disease merely require observation and x-ray from time to time. Often a period of bedrest with no physical activity is necessary to ease severe pain and limping.

Futher treatment may include:

• traction to the involved leg
• braces to hold the legs apart
• plaster cast for protection and support
• physiotherapy, including swimming
• use of a wheelchair to prevent weight-bearing
• surgery to insert metal plates and screws and to change the angle of the thigh bone.

Surgery in only necessary in 2% of all cases.