This 13-year-old boy fell 1-2 weeks ago and has been experiencing knee pain. You are shown one sagittal and one coronal water-weighted image of the lateral meniscus.
Q1 – What shall we name his diagnosis? Bonus points if you can also come up with the diagnosis this is known to simulate.
Sagittal T2
Coronal T2
His diagnosis is meniscal flounce.
The menisci are anchored at their root attachments and at the meniscocapsular junctions, including attachments to the femur and tibia as the meniscofemoral and coronary ligaments (see diagram). However, as one moves from the outer third to the inner third and middle third of the meniscus, the meniscus is not tethered or attached and floats freely. With small amounts of fluid and/or synovial thickening, the meniscus may assume a more wavy appearance and even appear crinkled.
This “crinkling” may simulate a meniscus tear, especially when arising from the femoral surface, tibial surface or along its tip sometimes simulating a radial tear.
Pearl: It has been reported that flounce can be a sign of meniscus hypermobility and intermittent locking. In summary, this is an example of a variation known as meniscal flounce.
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