Pathology:Inner fragment of torn meniscus is flipped
over ipsilateral anterior horn, and lies superior or posterior
to the normal anterior horn.Occurs more
frequently with medial, rather than lateral, meniscal tears.
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Imaging
findings:Abnormally large
anterior meniscus (8+ mm), measured in vertical dimension, with a
diminutive posterior horn (sagittal view).Alternatively, anterior lying fragment
results in elongated anterior horn with a band of high signal intensity differentiating
the anterior horn from the immediately adjacent (anterior or posterior)
flipped meniscal fragment.
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Note: The flipped
meniscus is frequently associated with concurrent fragment-in-notch
meniscal displacement.