Avascular Necrosis: Pathogenesis and Clinical Findings
• Physical Trauma (esp. to the scaphoid bone with damage to retrograde blood supply & the femoral head with damage to the circumflex vessels )
- Severing of blood vessels that perfuse bone
• Obstruction of Blood Flow
- Thrombophilia (blood clots)
- Alcoholism (fat microemboli)
- Sickle-cell disease (sickle crisis)
- Decompression (nitrogen bubbles)
• Multiple causes with unclear pathogenesis
- Glucocorticoid therapy
- Lupus (assoc. with steroid use)
- Radiation therapy (esp. TMJ affected)
- Acute pancreatitis
=> Hypoxic death of bone and hematopoietic marrow cells => Avascular Necrosis => Death Of bone and marrow
- Local bone pain
- Joint Locking or Catching (intermittent)
- X-Ray Findings
• Sclerosis surrounding necrotic region
• Collapsed bone segments
• Subchondral hypolucency "Crescent sign"
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