- Avascular necrosis (AVN) is death and eventual architectural collapse of bone as a result of ischemic injury or damage to bone or bone marrow elements. AVN most commonly affects the epiphysis of long bones; the hip (femoral head) is most susceptible but also can occur in the shoulder, knee, ankle, and wrist.
- Bone collapse at these joints can lead to cartilage breakdown and arthritis.
- About 20,000 to 30,000 new cases of AVN are reported each year.
- AVN usually affects people <50 years of age (1).
- Gender risk varies based on etiology.
Etiology and Pathophysiology
- Combination of metabolic, genetic, lifestyle, and environmental causes
- Traumatic (nonunion, Perthes disease, joint dislocation) accounts for most cases.
- Chronic glucocorticoid use and alcohol abuse account for >80% of nontraumatic (2).
- Bisphosphonates (AVN of the jaw) (1,2)
- Embolic (decompression disease, sickle cell)
- Systemic lupus erythematosus (SLE) (3)
- HIV and antiretroviral therapy
- Radiation and chemotherapy
- Avoid or limit medications and substances that can cause AVN, such as steroids or alcohol.
- Monitor fractures for signs of nonunion.
- High index of suspicion in high-risk population (SLE, steroid use, alcohol abuse)
- Early surgical intervention prior to joint collapse
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