Avascular Necrosis is the death of bone tissue which is caused by a loss of blood supply. Also termed osteonecrosis, it causes tiny breaks in the bone and eventually leads to the bone collapsing.
Blood flow to a section of a bone can be interrupted by a broken bone or dislocated joint. This condition is also associated with long-term use of high-dose steroid medications as well as excessive intake of alcohol.
Anyone can be affected by avascular necrosis, though the condition is more common among people between the ages of 30 and 50.
In the early stages of avascular necrosis, most people generally show no symptoms. However, as the condition gets worse, your affected joint is likely going to hurt when weight is put on it. Eventually, you might start experiencing the pain even while lying down.
Pain may be mild or severe and generally, it develops gradually. Pain which is associated with avascular necrosis of the hip can occur on the groin, thigh, or buttock. Other than the hip, the shoulder, knee, hand, and foot may also be affected.
Sometimes, people may also develop avascular necrosis on both sides, i.e. bilaterally.
If you think you have a dislocated joint or a broken bone, or if you experience persistent pain in any joint, it is important to seek immediate medical treatment.
Causes & risk factors
Certain factors that can lead to avascular necrosis or make it more likely include the following:
- Alcohol- If you take several drinks in a day, it can cause fat deposits to form in your blood. This can lower the blood supply to your bones.
- Medical treatments- Radiation therapy for cancer can weaken your bones. Other conditions linked to avascular necrosis include organ transplants, such as kidney transplants.
- Bisphosphonates- These medications which can help you boost bone density might also sometimes cause osteonecrosis of the jaw. This is more likely if you are taking them for multiple myeloma or metastatic breast cancer.
- Trauma- If you break or dislocate a hip, it might also cause damage to nearby blood vessels and cut off the blood supply to your bones. Avascular necrosis is known to affect 20% or more of people who dislocate a hip.
- Inflammation, blood clots, and damage to your arteries- All of these can block the blood flow to your bones.
- Steroid drugs- Long-term use of these inflammation-fighting drugs, either by mouth or in a vein, can lead to 35% of all cases of nontraumatic avascular necrosis. Doctors are unsure why, but the longtime use of certain medications can lead to avascular necrosis. It could be that the medications raise the fat levels in the blood, which lowers the blood flow.
Other conditions which are associated with nontraumatic avascular necrosis include:
- Decompression sickness, which causes gas bubbles in your blood
- Pancreatitis, inflammation of the pancreas
- Autoimmune diseases such as lupus
- Gaucher disease, in which a fatty substance collects in the organs
- Sickle cell disease
During a physical exam, a doctor is likely going to press around your joints, and check for tenderness. Your doctor might also need to move the joints through different positions, to see, if your range of motion has been reduced.
Your doctor can also recommend certain imaging tests, to help pinpoint the source of pain.
Some of the options include:
MRI and CT scan
Treatment for avascular necrosis aims to improve the joint, stop the bone damage, and ease any pain. The best treatment is going to depend on a number of factors, such as your age, the stage of the disease, the cause, as well as the location and amount of bone damage.
If you catch the ailment early, doctors generally recommend medications to relieve pain. Medications can include blood thinners, cholesterol drugs, etc.
If your avascular necrosis is fairly advanced, your doctor is likely going to recommend any of the following:
Bone transplant (graft)
Bone reshaping (osteotomy)
To prevent avascular necrosis, you can take the following steps:
Cut back on alcohol- Heavy drinking is a leading risk factor for avascular necrosis.
Use steroids carefully- Taking steroids over and over again can worsen bone damage.
Keep your cholesterol in check- Small bits of fat are the most common thing that is known to block the blood supply to your bones.
Don’t smoke- Smoking boosts your risk of avascular necrosis.