Osteonecrosis
Osteonecrosis, also known as avascular necrosis or ischemic necrosis, is a disorder characterized by the death of bone tissue due to a lack of blood supply. This condition typically affects the hips, knees, and joints, and can arise from various causes, including trauma, prolonged corticosteroid use, excessive alcohol consumption, and certain medical treatments. Symptoms often begin subtly, presenting as joint pain that worsens over time, leading to joint collapse and increased discomfort, even at rest.
The average age of onset is around 38, with approximately 20,000 new cases diagnosed annually in the United States. Both men and women are equally affected, and certain risk factors, such as previous injuries or underlying bone disorders, may increase susceptibility. Diagnosis usually involves imaging techniques like X-rays or MRI to assess the condition of the bones.
Treatment for osteonecrosis can be both medical and surgical, depending on the severity of the condition and the patient's specific circumstances. Medical options include pain management with nonsteroidal anti-inflammatory drugs (NSAIDs), anticoagulants to improve blood flow, and statins to reduce lipid buildup. Surgical interventions may involve procedures such as core decompression, bone grafting, or even joint replacement in advanced cases. Early diagnosis and intervention are critical to managing the disease and preserving joint function.
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Subject Terms
Osteonecrosis
ALSO KNOWN AS: Aseptic necrosis, avascular necrosis, ischemic necrosis
ANATOMY OR SYSTEM AFFECTED: Bones, hips, joints, knees, musculoskeletal system
DEFINITION: A disorder that occurs when the blood supply to bone is cut off, causing the death of bone tissue and leading to the collapse of joints in the affected areas
CAUSES: Interruption of blood supply to bone; may result from trauma, corticosteroid use, excessive alcohol consumption, bone disorders, cancer treatment
SYMPTOMS: Joint pain and loss, death of bone tissue
DURATION: Chronic and progressive
TREATMENTS: Nonsteroidal anti-inflammatory drugs (NSAIDs), anticoagulants, statins, exercises, electrical stimulation, surgery (core decompression, bone grafting, osteotomy, joint replacement)
Causes and Symptoms
Osteonecrosis—from osteo, meaning “bone,” and necro, meaning “death”—may be either posttraumatic or nontraumatic, in some cases with identified and in others with no known cause (idiopathic). Approximately twenty thousand new cases are diagnosed each year in the United States, most commonly between the ages of twenty and fifty, with the average age of onset at thirty-eight. Osteonecrosis is of equal prevalence in men and women.
Some risk factors seem to predispose people to osteonecrosis, including the use of corticosteroids (to treat inflammatory conditions) as well as excessive alcohol ingestion. Both steroid and use may lead to a buildup of in the blood vessels, decreasing blood flow to bones. Injury to a bone or joint (such as a fracture) may damage the blood vessels, decreasing the blood supply and causing bone death. Medical conditions which affect the bone (gout, osteoarthritis, osteoporosis) may predispose someone to osteonecrosis. Cancer treatments (radiation and chemotherapy) and organ also increase the risk of osteonecrosis, as do other medical conditions including and Acquired immunodeficiency syndrome (AIDS). The medication Fosamax, a bisphosphenate used to treat osteoporosis, has been linked to osteonecrosis of the jaw.
Often, few symptoms occur in early stages of the disease. Preliminary symptoms include pain in the affected joint, followed by collapse of joint surfaces and increased pain. Pain occurs initially only when the joint is in use and later even at rest. The most commonly affected are the ends of the femur, the bone, and the knees, shoulders, and ankles. Within months to two years from the onset of symptoms, individuals may lose range of motion and suffer severe disability. Appropriate treatment must be undertaken to prevent the breakdown of joints, Therefore, immediate diagnosis is important. X-rays, magnetic resonance imaging (MRI), computed tomography (CT) scan, and bone scans serve as diagnostic tools when an individual is symptomatic.
Treatment and Therapy
Once the condition has been diagnosed, treatment should begin immediately. To decide on most effective treatments, physicians consider the age of the patient, the progression of the disease, the location of the bones involved, and the underlying cause. Treatment can be either medical or surgical. Medical treatments include the use of nonsteroidal (NSAIDs) to decrease pain, anticoagulants (blood thinners) to improve blood supply to bone, and statins (cholesterol-lowering medications) to decrease lipid buildup in blood vessels, allowing improved blood flow to bone. Other medical treatments involve range of motion exercises, electrical stimulation to induce bone growth, and decreased weight-bearing on affected joints.
Surgical techniques used to treat osteonecrosis include core decompression, bone grafting, osteotomy, and joint replacement. In core decompression, the inner core of the bone is removed, thus reducing pressure within the bone. Core decompression is often followed by bone grafting to the decompressed area to support the joint. Osteotomy is a surgical reshaping of the bone to decrease stress on affected areas. Joint replacement is the surgical treatment of choice in advanced cases. Treatment may be an ongoing process that continues for years, as the disease progresses. Adequate treatment allows afflicted individuals to continue to live reasonably normal lives.
Bibliography
"Avascular Necrosis (Osteonecrosis)." Mayo Clinic, 17 May 2022, www.mayoclinic.org/diseases-conditions/avascular-necrosis/symptoms-causes/syc-20369859. Accessed 7 Apr. 2024.
Bianchi, Giancarlo I., and Pascual C. Giordano. Osteonecrosis: Diagnosis, Treatment, and Management. New York: Nova Science, 2013.
Icon Health. Osteonecrosis: A Medical Dictionary, Bibliography, and Annotated Research Guide to Internet References. San Diego, Calif.: Author, 2004.
Mont, Michael A., et al. Osteonecrosis of the Hip. New York: Springer, 2010.
National Institute of Arthritis and Musculoskeletal and Skin Diseases. Osteonecrosis: Questions and Answers About Osteonecrosis (Avascular Necrosis). Bethesda, Md.: US Department of Health and Human Services, 2011.
National Osteonecrosis Foundation. http://www.nonf.org.
Soucacos, Panayotis N., and James R. Urbaniak, eds. Osteonecrosis of the Human Skeleton. Philadelphia: W. B. Saunders, 2004.
Urbaniak, James R., and John Paul Jones, eds. Osteonecrosis: Etiology, Diagnosis, and Treatment. Rosemont, Ill.: American Academy of Orthopaedic Surgeons, 1997.
Zheng, Haotian, et al. "Laboratory Indices in Patients with Osteonecrosis of the Femoral Head: A Retrospective Comparative Study." Journal of Orthopaedic Surgery & Research, vol. 18, no. 750, 4 Oct. 2023, doi.org/10.1186/s13018-023-04235-0. Accessed 7 Apr. 2024.