Causes of Avascular Necrosis, Risk Factors and Symptoms
Avascular necrosis is a condition in which bone tissue dies because of a lacking blood supply. This condition, also referred to as osteonecrosis, may result in eventual bone collapse and tiny breaks in the bone. This condition becomes worse over time. The hip joint is most commonly affected. Knowing the causes of avascular necrosis can help patients to avoid this condition.
The three most common risk factors of this condition include:
Drinking heavily: Drinking multiple alcoholic drinks per day for a period of several years, may cause fatty deposits to develop in the patient’s blood vessels. These deposits can result in restricted blood flow to the bones.
Corticosteroids: This type of medication, when taken in high doses for a prolonged period of time, may cause this condition.
Bisphosphonates: This type of medication is used to treat osteoporosis-related bone weakening. Patients taking this type of medication are at a higher risk for developing this condition of the jaw. Those receiving this medication in high doses via intravenous route are at the highest risk.
Certain medical procedures may increase a patient’s risk, including:
- Cancer treatments like radiation or chemotherapy
- Kidney transplants or other organ transplants
Medical conditions that could increase a patient’s risk include:
- Legg-Calve-Perthes Disease
- Sickle cell anemia
- Gaucher’s disease
- Kienbock’s disease
This is one of the possible causes of avascular necrosis. A dislocated joint or broken bone may result in the destruction or damage to nearby blood vessels. Bone cells die when they are not fed a steady supply of nutrients and oxygen.
Pressure Inside the Bone
This possible cause can make it harder for fresh blood to get in. Certain treatments or conditions, such as Gaucher’s disease or Legg-Calve-Perthes disease can increase the pressure inside the bone.
Narrowed Blood Vessels
Blood flow going to a bone may be reduced if it travels through a narrowed or clogged vessel. A very small bit of fat is a common cause of this problem. In patient’s with sickle cell anemia, deformed blood cells may clump together causing this.
The symptoms of this condition usually include reduced range of motion and pain in affected joints. The most commonly affected joints include:
- Knee: The pain is most often present on the inner knee and becomes worse with activity
- Hip: The pain will be in the hip joint and may go down the groin. It may also go down to the knee, through the thigh
- Shoulder: The upper arm bone is most often affected by this condition
Some patients experience no symptoms, some patients experience gradual, chronic symptoms, and some patients experience more acute symptoms. In addition to the joints listed above, other joints may also be affected, including:
MedlinePlus. (2009). Osteonecrosis. Retrieved on September 14, 2010 from MedlinePlus: https://www.nlm.nih.gov/medlineplus/ency/article/007260.htm
MayoClinic.com. (2010). Avascular Necrosis. Retrieved on September 14, 2010 from MayoClinic.com: https://www.mayoclinic.com/health/avascular-necrosis/DS00650