Ficat and Arlet staging of hip avascular necrosis

Professor R.P. Ficat and professor J. Arlet in the late 70s devised a staging system for idiopathic bone necrosis of femoral head based on two fundamental concepts:

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


Stage 0

  • pre clinical and pre radiographic
  • suspected in one hip when other hip has definite disease (high incidence of bilateral involvement)

Stage I

  • earliest clinical manifestation of syndrome
  • sudden groin pain
  • progressive, radiation to thigh, often worse at night
  • pain may be aggravated by coughing
  • limited hip movement
  • standard AP and lateral radiographs
    • usually normal, or
    • show minor changes – subtle loss of clarity with poor definition or blurring of trabecular pattern; some slight patchy osteoporosis may be seen

Stage II

  • extends over several months
  • clinical signs persist or worsen
  • changes in trabecular pattern of femoral head
  • sclerosis – diffuse, localized or in a linear arc which is concave superiorly
  • decalcification may be generalized or in the form of small cysts in the head, usually at some distance from the joint space
  • mixed form – sclerosis and cysts may be seen

Transition phase

  • crescentic line due to a subchondral fracture
  • segmental flattening of femoral head resulting in ‘out of round’ appearance

Stage III

  • increasing, more constant pain
  • limitation of movement in all directions
  • progressive functional incapacity – limp requiring use of a stick
  • pathognomic appearance of sequestrum in radiograph
  • break in articular margin followed by collapse of sequestrated area into femoral head
  • paradoxical preserved or increased joint space in view of limited sequestrum size

Stage IV

  • terminal phase of necrotic process
  • progressive loss of articular cartilage
  • development of acetabular osteophytes
  • osteoarthritis imposed on a deformed femoral head
Two variations identified
  1. Ischaemic coxopathy
    • narrowing of joint space in early stages of disease – generalized or confined to superomedial quadrant
    • mis diagnosed as primary osteoarthritis in early stages
    • seen in 6th decade
    • sudden onset with pain in night
    • morphologically normal as well as dysplastic hips
  2. Bilateral involvement
    • 50% cases of idiopathic bone necrosis
    • 80% of steroid associated bone necrosis
    • frequently asymmetrical involvement

Read more

Ficat, R. P. “Idiopathic bone necrosis of the femoral head. Early diagnosis and treatment.”Bone & Joint Journal 67.1 (1985): 3-9.