Avascular Necrosis



  • 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)

Risk Factors

  • Systemic lupus erythematosus (SLE) (3)
  • HIV and antiretroviral therapy
  • Radiation and chemotherapy

General Prevention

  • 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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