Definition and Overview

Avascular necrosis is a painful condition caused by reduced blood supply to the bone. Without enough blood supply, the bone will slowly break down and eventually die. Also known as osteonecrosis, it can affect any bone and joint in the body. However, it is more common in the ankles, shoulders, knees, and hips. If left untreated, it leads to severe arthritis that can prevent a person from using the joint again.

The disorder can be caused by certain diseases or severe trauma to the joint. However, in some cases, the cause is unknown. With available treatments, its progression can be slowed down. However, many patients would eventually require surgery.

The condition occurs in about 200,000 people in the United States every year. It can affect any person of any age but is most common in people older than 30 years old. When diagnosed and treated early, many patients fully recover without lasting health problems.

Causes of Condition

The disorder occurs when bones or joints do not receive enough blood supply. This can happen due to:

  • Blood vessel problems - Blood vessels can narrow due to fatty deposits. They can also be blocked by blood clots. Both can limit the amount of blood that goes through them.

  • Severe trauma to the bone - Dislocated or broken bones can disrupt normal blood flow.

  • Arthritis - Arthritis causes joints to swell. Examples of arthritis that are associated with avascular necrosis are gout, osteoarthritis, and rheumatoid arthritis.

Factors that can increase one’s risk of developing the condition are:

  • Diabetes, or high blood sugar levels

  • Sickle cell anemia, which can cause bone loss

  • Excessive alcohol consumption, which can cause fatty deposits to form in blood vessels.

  • Gaucher’s disease - A disease caused by the build-up of fatty substances in certain organs, causing them to enlarge and malfunction.

  • HIV/AIDS

  • Long-term use of bisphosphonates - Bisphosphonates are used to treat conditions that affect the bones. However, their prolonged use is associated with an increased risk of osteonecrosis of the jaw.

  • Organ transplantation

  • Pancreatitis

  • Radiation therapy - Studies have shown that this cancer treatment can increase the risk of bone loss.

  • Steroid use - Long-term use of corticosteroids is associated with more than 30% of all reported cases of avascular necrosis. Although it is not clear as to how these drugs contribute to the development of the condition, doctors believe that it has something to do with how they prevent the body from properly breaking down fatty substances.

  • Systemic lupus erythematous - A chronic disorder that inflames the body’s connective tissues. It can affect many organs as well as the bones.

Key Symptoms

The disorder does not cause symptoms in the beginning. But when it starts to get worse, pain can be felt when weight or pressure is placed on the affected bone or joint. The pain usually subsides when the person rests. However, if the disease is left untreated, severe pain can be felt even when resting.

Who to See and Types of Treatments Available

The condition is diagnosed and treated by bone specialists (orthopaedic doctors or surgeons). These doctors usually order an x-ray when patients complain of bone pain. X-rays can show bone problems and changes that may explain the symptom. More sensitive imaging tests are then ordered to gather more information. These include magnetic resonance imaging (MRI) as well as computed tomography (CT) and bone scans.

Treatment depends on the severity of the condition. If caught in the early stages, it is treated with medications. Drugs that are prescribed to relieve symptoms and prevent the condition from worsening are as follows:

  • Anti-inflammatory drugs

  • Blood thinners

  • Cholesterol-lowering drugs

  • Pain relievers

Doctors may also recommend the following:

  • Physical therapy, to improve the joint’s range of motion

  • Rest - Patients can be advised to avoid putting weight or pressure on the affected joint or bone until it heals. They may do so by taking complete bed rest or using a wheelchair.

The above treatments can slow down the progression of the disease. However, most patients would eventually require surgery. Procedures used to treat the condition are:

  • Bone graft-– A healthy bone is taken from other parts of the patient’s body. It is then transplanted to the affected area to provide support.

  • Osteotomy - The damaged bone is cut and its alignment is changed. This helps reduce pressure on the affected bone or joint.

  • Core decompression - A part of the inside of the bone is removed to allow new blood vessels to form.

References:

  • Whyte MP. Osteonecrosis, osteosclerosis/hyperstosis, and other disorders of the bone. In: Goldman L, Schafer AI, eds. Goldman’s Cecil Medicine . 24th ed. Philadelphia, Pa.: Elsevier Saunders; 2011:chap 256.

  • Questions and answers about osteonecrosis (avascular necrosis). National Institute of Arthritis and Musculoskeletal and Skin Diseases. http://www.niams.nih.gov/Health_Info/Osteonecrosis/default.asp.

  • Firestein GS, et al. Kelley’s Textbook of Rheumatology. 9th ed. Philadelphia, Pa.: Saunders Elsevier; 2013. http://www.clinicalkey.com

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