Ficat and Arlet classification of avascular necrosis of femoral head

Last revised by Subhan Iqbal on 06 Nov 2022

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

  • 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

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

  1. a standard radiograph shows only the shadow of the mineralized portion of a bone

  2. bone necrosis is the end result of severe and prolonged ischemia

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Cases and figures

  • Case 1: stage II
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  • Case 2: stage III
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  • Case 3: stage II
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  • Case 4: stage III
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  • Case 5: stage IV
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  • Case 6: stage IV
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  • Case 7: stage III
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