Ficat and Arlet classification of avascular necrosis of femoral head

The Ficat and Arlet classification uses a combination of plain radiographs, MRI, and clinical features to stage avascular necrosis of the femoral head.

Classification

• stage 0
  • plain radiograph: normal
  • MRI: normal
  • clinical symptoms: nil
• stage I
  • plain radiograph: normal or minor osteopenia
  • MRI: edema
  • bone scan: increased uptake
  • clinical symptoms: pain typically in the groin
• stage II
  • plain radiograph: mixed osteopenia and/or sclerosis and/or subchondral cysts, without any subchondral lucency (crescent sign: see below)
  • MRI: geographic defect
  • bone scan: increased uptake
  • clinical symptoms: pain and stiffness
• stage III
  • plain radiograph: crescent sign and eventual cortical collapse
  • MRI: same as plain radiograph
  • clinical symptoms: pain and stiffness +/- radiation to knee and limp
• stage IV
  • plain radiograph: end-stage with evidence of secondary degenerative change
  • MRI: same as plain radiograph
  • clinical symptoms: pain and limp

History and etymology

Professor R.P. Ficat in association with Professor J. Arlet devised a system of staging idiopathic avascular necrosis of femoral head in the late 1970s based on two fundamental concepts ²: 

1. a standard radiograph shows only the shadow of the mineralised portion of a bone
2. bone necrosis is the end result of severe and prolonged ischemia

See also

• avascular necrosis
• avascular necrosis of the hip
• Steinberg staging