Presentation
Recent knee pain. History of minor knee trauma.
Patient Data
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![This study is a stack](/packs/stack-YQKLCKBI.gif)
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![This study is a stack](/packs/stack-YQKLCKBI.gif)
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![This study is a stack](/packs/stack-YQKLCKBI.gif)
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![This study is a stack](/packs/stack-YQKLCKBI.gif)
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The medial femoral condyle shows subchondral irregular line of persistent low signal, surrounded by extensive marrow edema signal of the medial femoral condyle.
Knee osteoarthritis.
Mild joint effusion.
Degeneration of the posterior horn of the medial meniscus.
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![This study is a stack](/packs/stack-YQKLCKBI.gif)
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![This study is a stack](/packs/stack-YQKLCKBI.gif)
![](https://prod-images-static.radiopaedia.org/images/52377686/f0d3956059b9ec5a28aa0766bf7464_big_gallery.jpeg)
The left medial femoral condyle shows subtle subcortical sclerotic line with adjacent subcortical pseudocystic changes.
Case Discussion
Subchondral insufficiency fracture of the knee (SIF/SIFK) are stress fractures in the femoral condyles or tibial plateau that occur in the absence of acute trauma, typically affecting older adults.
The entity subsumes that previously known as spontaneous osteonecrosis of the knee (SONK/SPONK) or Ahlbäck disease.