Osteonecrosis of the Hip | AVN

Western Health Orthopaedic Registrar presenation - 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 lineĀ® 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)
    Classification of Osteonecrosis of the Hip
    Stage Description
    1 + 2
    • A mild: less than 15% involvement of head on XR or MRI
    • B mod: 15- 30%
    • C severe: more than 30%
    3
    • A: subchondral collapse (crescent) less than 15% of artic surface
    • B: 15- 30%
    • C: more than 30%
    4
    • A: 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
    5
    • A,B or C average of femoral hd involvement as in stage 4
    • Head involvement = % of head on AP view x % head on lateral view
      • Eg 25 % involvement may be 50 % AP & 50 % lateral