Spontaneous osteonecrosis of the knee (SONK)

Case contributed by Dr Fazel Rahman Faizi


Knee pain without history of any trauma.

Patient Data

Age: 40 years
Gender: Male

A focal area of bone marrow edema and subtle flattening of the medial femoral condyle is noted along with irregular hypointense line in subchondral region representing granulation tissue/callus formation. Overall features are compatible with spontaneous osteonecrosis of the knee (SONK).

Linear high T2/PD fat sat horizontal oblique high signal intensity is noted within posterior horn of the medial meniscus reaching the articular surface representing a horizontal meniscal tear.

Case Discussion

Spontaneous osteonecrosis of the knee joint mainly involves the medial femoral condyle. Localized vascular insufficiency is presumed to play role in necrosis and subsequent disruption of the nutrition supply to the above cartilage.

Dr. Farhad Farzam has also contributed to this case.

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Case information

rID: 66265
Published: 15th Feb 2019
Last edited: 21st Feb 2019
Inclusion in quiz mode: Included
Institution: French Medical Institute for Mothers and children

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