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.
On this page:
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
The French orthopedic surgeon Paul (RP) Ficat (1917-1986) 4 in association with Professor Jacques Arlet devised a system of staging idiopathic avascular necrosis of femoral head in the late 1970s based on two fundamental concepts 2:
- a standard radiograph shows only the shadow of the mineralized portion of a bone
- bone necrosis is the end result of severe and prolonged ischemia