AVN affects around 10,000 to 20,000 people each year in the United States. Those affected are usually between the ages of 30 and 50, but it can affect people of all ages. AVN affects both men and women.

The specific cause of AVN varies across individuals. However, the condition is most commonly caused by serious trauma (injury), fracture, damage to blood vessels, long-term use of corticosteroids, excessive alcohol consumption and certain medical conditions, such as lupus (an autoimmune disease resulting in the body’s immune system attacking its own tissues and organs, causing inflammation and pain in parts of the body).

There are a few common symptoms experienced by individuals with AVN, however these symptoms can vary across individuals. In the early stages of AVN, patients may not have any symptoms. As the disease progresses, it is common for patients to start experiencing joint pain when applying weight to the affected area or even when resting. The pain will gradually worsen and may be mild to severe. In later stages of AVN with the bone and surrounding joint surface collapsing, pain can increase rapidly. The time between early and later stages of AVN will vary for each person and may take several months to several years.

AVN is typically suspected when a patient notifies their doctor of experiencing or feeling bone pain in a localized area (limited to the small area concerned). A doctor will usually perform a physical examination and assess the patient’s medical history. Thereafter, certain imaging techniques will be used to diagnose the patient with AVN.

An X-ray is likely to be the first diagnostic test the doctor suggests. Since x-rays may not detect AVN in the early stages, other tests may be performed. These include:

• Magnetic Resonance Imaging (MRI) - An MRI uses a magnetic field and radio waves to produce detailed images of organs and structures within the body. 

• Computed/Computerized Tomography (CT) - A CT scan is used to provide a three-dimensional image of the bone. It can also show slices of the bone, which produces a clearer picture of the overall bone than x-rays and bone scans. CT scans may not detect early-stage AVN as MRI scans usually do, but they can indicate cracks in the bone. 

• Biopsy - In some cases, a biopsy may be performed to examine bone tissue samples. This is a procedure in which a sample of body tissue, cells or fluid is removed from the body and examined in a laboratory.

Early intervention is essential to preserve the bones affected, but people are often diagnosed later in the disease process. Depending on factors, such as the patient’s age, stage of AVN, location and amount of damage, the doctor will determine the most appropriate treatment. The overall aim of treatment is to improve the patient’s use of the affected area, prevent further damage to the bone, and ensure the survival of the bone and joint. Common treatments for AVN include:

• Core decompression - This procedure removes or drills a tunnel into the affected bone area to reduce pressure inside the bone. This procedure is best used to treat earlier stages of AVN, before collapse of the bone. 

• Osteotomy - This procedure aims to reshape the bone to reduce stress to the affected area. Dead bone is removed and the remaining bone is re-positioned or shaped to enable the healthy bone to support the weight-bearing joint surface. 

• Bone grafting - In more advanced cases, bone grafting surgery may be used. This involves using a small piece of the patient’s healthy leg bone and transplanting (grafting) it to the area of dead bone. This procedure aims to improve blood flow and provide support to the surrounding bone. 

• Arthroplasty - If the patient’s joint has already collapsed, a total joint replacement may be necessary to replace the affected joint with artificial parts.

For most individuals with AVN, treatment tends to be an ongoing process and the length of time for treating the damaged area varies across individuals. While there is currently no proven medical therapy for AVN, studies continue to investigate the disease to develop a better understanding of how it occurs and the effectiveness of current and new treatments.

To prevent further bone damage and to reduce the likelihood of developing AVN in other areas, it is recommended to avoid excessive alcohol consumption and avoid tobacco use, as smoking has been linked to heightened risk of AVN.

American College of Rheumatology. Osteonecrosis. 2019. Available from: https://www.rheumatology.org/I-Am-A/Patient-Caregiver/Diseases-Conditions/Osteonecrosis

John Hopkins Medicine. Avascular Necrosis 2020. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/avascular-necrosis

National Organization for Rare Disorders. Osteonecrosis. 2018. Available from: https://rarediseases.org/rare-diseases/osteonecrosis/#:~:text=Osteonecrosis%2C%20also%20known%20as%20avascular,to%20an%20irregular%20joint%20surface.