Avascular Necrosis

What is Avascular Necrosis of the hip?

Avascular Necrosis (AVN) is a disease where the bone of the femoral head (ball of the hip joint) is damaged by a loss of blood supply. The damaged bone becomes softened and liable to collapse, resulting in deformity of the femoral head and separation of the overlying cartilage. In the late stages of AVN, progressive damage to the hip joint results in early osteoarthritis.

Why does AVN develop?

In many situations, no cause is identified (also known as 'Idiopathic AVN'). Known risk factors for developing AVN include the use of corticosteroid medications, high alcohol consuption abuse and hip joint trauma (dislocations and fractures).

How long will my hip joint last?

This is sometimes a difficult question to answer, and depends on a number of factors. In the early stages of AVN, good medium term results can be obtained with the use of bisphosphonate (tablet) medications. Once collapse of the femoral head has occured, the outcome for the hip joint is less favourable, however the outlook can still be improved in selected cases with surgical intervention. Hip joints with significant collapse and deformity of the femoral head due to AVN reliably develop early onset osteoarthritis.

What treatments are available?

In the early stages AVN, progression of the disease can be prevented or slowed with the use of bisphosphonate medications (used to improve bone density). Pain associated with AVN can often be significantly improved with a minimally invasive drilling procedure (Forage). After collapse of the femoral head has occured, the outcome for the hip joint is less favourable. In some cases, a procedure to protect the softened area of the femoral head by reshaping the upper thigh bone (femoral osteotomy) may be recommended. Ultimately, hip joints with end stage AVN and associated osteoarthritis are best treated with an artificial joint replacement. In these situations, both hip replacement and hip resurfacing have been shown to be effective.

This information has been written by Dr Patrick Weinrauch for the purposes of patient education. The details provided are of general nature only and do not substitute for professional recommendations based an individual clinical assessment.