Epidemiology

Etiology

Though often idiopathic, several traumatic and atraumatic factors may contribute to the development of osteonecrosis.

• Atraumatic factors
  • Glucocorticoid use (35–40% of cases)
  • Alcohol use disorder (20–40% of cases)
  • Legg-Calvé-Perthes
  • Hemoglobinopathies (e.g., sickle cell disease)
  • Autoimmune diseases (e.g., SLE, antiphospholipid syndrome)
  • Pancreatitis
  • Infection
  • Gaucher disease
  • Decompression sickness
• Traumatic factors
  • Femoral neck fractures, particularly with dislocation
  • Femoral head fracture
  • Slipped capital femoral epiphysis (SCFE)

Pathophysiology

Clinical features

Diagnostics

Imaging

• X-ray: best initial test
  • Findings
    • Cystic and sclerotic changes in the femoral head
    • Subchondral collapse
    • Flattening of the femoral head
• MRI: confirmatory test
  • Findings
    • Visualization of the interface between necrotic and viable bone

Treatment