Avascular- Osteonecrosis

Question 1

Def.

Answer 1

• Death of osseous cellular bone.

Question 2

Aetiology

Answer 2

• Commonly idiopathic or spontaneous.
• Prediliction for epiphyseal areas.
• Usually isolated lesions:
  
  • femoral capital epiphysis,
  • distal femurs,
  • met heads.
• May be secondary to
• trauma,
• drugs,
• radiation,
• pancreatitis,
• gout

Question 3

Radiol Fx.

Answer 3

• Commonly seen in epiphyseal centres especially:
  
  • femoral head,
  • humeral head,
  • distal femur,
  • metaphyseal
  • diaphyseal areas of long bones.
• May see:
  
  • Epiphyseal Infarction,
  • Fragmentation,
  • mottled trabecular pattern,
  • sclerosis,
  • subchondral cysts,
  • subchondral fractures
• N.B. importance of Crescent Fracture Sign