Osteonecrosis of the Hip | AVN

Western Health Orthopaedic Registrar presentation – Osteonecrosis of the femoral head by Dr Devinder Garewal

Classification

Ficat Classification

  • Professor RP Ficat; Ficat Classification of Osteonecrosis of the Hip
    • Normal hip with contra-lateral disease (Hungerford)
  • I
    • Normal radiograph
    • Diagnosis following MRI, bone scan or histology
  • II
    • Radiographic changes of repair (osteoporosis / sclerosis / cysts)
    • No osteochondral fracture
    • Head spherical
  • III
    • Wedge shaped ↑ density
    • Mottled osteoporosis
    • Subchondral lucent line® Crescent sign
    • Head no longer spherical “out of round”
    • Usually affects antero-lateral area of femoral head (best seen on lateral view)
  • IV
    • Marked changes with secondary degenerative changes in the joint
    • Collapse of subchondral bone & severe deformity of the head
  • Steinberg Classification
    • Steinberg etal JBJS (Journal of Bone & Joint Surgery) 77B: 34-41,1995
      • Modified to assess extent of involvement
      • More accepted classification
    • Steinberg Classification of Osteonecrosis of the Hip
* Normal hip with contra-lateral disease (Hungerford)
* Suspicion but unable to confirm
I* Normal radiograph
* Diagnosis following MRI, bone scan or histology
II* Radiographic changes of repair (osteoporosis / sclerosis)
* No osteochondral fracture
* Head spherical
III* Wedge shaped ↑ density
* Mottled osteoporosis
* Subchondral lucent line (Crescent sign)
* Head no longer spherical “out of round”
* Usually affects antero-lateral area of femoral head (best seen on lateral view)
IV* Flattening of the femoral head
* On AP or lateral XRAYS
* Now irreversible changes
* Symptomatic treatment until arthroplasty
V* joint narrowing with or without
* acetabular involvement
VI *advanced degenerative changes
These stages are further divided into mild (A), moderate (B) or severe (C)
Stage Description
1 + 2A mild: less than 15% involvement of head on XR or MRI
B mod: 15- 30%
C severe: more than 30%
3A: subchondral collapse (crescent) less than 15% of artic surface
B: 15- 30%
C: more than 30%
4A: less than 15% of surface has collapsed + depression is less than 2 mm
B: 15- 30% collapsed or 2-4 mm depression
C: more than 30% collapsed or more than 4mm depression
5A,B or C average of femoral hd involvement as in stage 4
Classification of Osteonecrosis of the Hip

Head involvement = % of head on AP viewx % head on lateral view

  • Eg 25 % involvement may be 50 % AP & 50 % lateral