Subchondral insufficiency fracture

Last revised by Francis Deng on 05 Apr 2021

Subchondral insufficiency fracture refers to a type of stress fracture that occurs below the chondral surface on a weight-bearing surface of a bone due to mechanic failure of subchondral cancellous bone.

They tend to occur when normal physiological forces are repeatedly applied to an area of bone. Callus formation occurs along with non-mineralized osteoid and the absence of bone infarction.

  • osteoporosis
  • obesity
  • abnormal loading through the joint
  • overuse

Typical sites include:

  • secondary osteonecrosis
  • osteonecrosis with cavitation (crescent sign)
  • articular collapse
  • destructive arthropathy

Radiographs are normal preceding the development of callus formation or collapse of the articular surface. Linear or patchy subchondral sclerosis may be present representing cancellous fracture.

  • T1: may be characteristically low signal intensity band through the affected region
    • parallels the subchondral bone plate whereas osteonecrosis is curvilinear
    • preservation of the articular cartilage whereas an osteochondral defect is involved
  • T2: florid marrow edema

It is described in many regions but the term subchondral insufficiency fracture of "femoral head" was coined by Bangil et al in 1996 7.

The differential diagnosis of subchondral marrow edema includes:

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Cases and figures

  • Case 1: metatarsal head
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  • Case 2: knee
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  • Case 3: knee
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  • Case 4: metatarsal head
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  • Case 5
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  • Case 6
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  • Case 7
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