Aseptic Necrosis

Avascular necrosis is a condition in which bone tissue dies because it does not receive enough blood. It is also known as osteonecrosis. When blood flow to a bone is reduced or stopped, tiny breaks can form in the bone structure, eventually causing the bone to weaken and collapse. This process may take months or even years to develop.

An injury such as a broken bone or a dislocated joint can interrupt blood flow to a specific area of bone. Avascular necrosis is also linked to long-term use of high-dose steroid medicines and excessive alcohol consumption.

Although anyone can develop avascular necrosis, it most commonly affects people between 30 and 50 years of age.

Symptoms

In the early stages of avascular necrosis, some people may have no symptoms. As the condition progresses, pain usually develops in the affected joint.

At first, joint pain may occur only when putting weight on the joint. Over time, the pain can become constant and may occur even while resting or lying down.

The pain may range from mild to severe and often develops gradually. When avascular necrosis affects the hip, pain is commonly felt in the groin, thigh or buttock. Other joints that may be affected include the shoulder, knee, hand and foot.

In some cases, avascular necrosis develops on both sides of the body, such as in both hips or both knees.

When to see a doctor

Consult a health care professional if you experience ongoing pain in any joint. Seek immediate medical attention if you suspect a broken bone or a dislocated joint.

Causes

Avascular necrosis occurs when blood flow to a bone is reduced or interrupted. Several factors can cause this decrease in blood supply.

Common causes include:

• Joint or bone trauma, such as a fracture or dislocation, which can damage nearby blood vessels

• Cancer treatments involving radiation therapy, which can weaken bones and damage blood vessels

• Fatty deposits in blood vessels, also called lipids, which can block small blood vessels and reduce blood flow

• Certain medical conditions that affect circulation, including sickle cell anemia, lupus, antiphospholipid syndrome and Gaucher disease

In some cases, avascular necrosis develops without a clear cause. Genetics, alcohol overuse, certain medications and underlying diseases are thought to contribute.

Risk factors

Several factors increase the risk of developing avascular necrosis.

These risk factors include:

• Trauma, such as fractures or joint dislocations that damage blood vessels

• Long-term use of high-dose corticosteroids, including medicines like prednisone

• Heavy alcohol consumption over many years, which can lead to fatty deposits in blood vessels

• Long-term use of bisphosphonates, particularly at high doses for cancer treatment, which may increase the risk of osteonecrosis of the jaw

• Certain medical treatments, such as radiation therapy and organ transplants, especially kidney transplants

Medical conditions associated with avascular necrosis include:

• Pancreatitis

• Gaucher disease

• HIV/AIDS

• Systemic lupus erythematosus

• Sickle cell anemia

• Decompression sickness, also known as diver’s disease

• Certain cancers, such as leukemia

Complications

If left untreated, avascular necrosis usually worsens over time. As blood supply continues to decline, the affected bone may collapse.

The condition can also cause the bone to lose its smooth shape, which may lead to early and severe arthritis. Joint damage can significantly reduce mobility and quality of life.

Prevention

Certain lifestyle choices may help reduce the risk of avascular necrosis and support overall bone health.

Helpful preventive measures include:

• Limiting alcohol intake, as heavy drinking is a major risk factor

• Keeping cholesterol levels under control to reduce fat buildup in blood vessels

• Monitoring steroid use and informing your health care professional about past or current high-dose steroid treatment

• Avoiding smoking, which narrows blood vessels and reduces blood flow to bones

Managing underlying medical conditions and maintaining regular medical follow-up may also help lower the risk of developing avascular necrosis.