A FEW MRI MENISCUS ABNORMALITIES: MENISCUS TEAR, INTRA MENISCAL CYST AND VARIANTS THAT LOOK LIKE TEARS

WHAT ARE THE FINDINGS?

Cystic structure (Pink arrow) present within the anterior horn.

WHAT'S THE Dx?

INTRAMENISCAL CYST

• Extensive intra meniscal cyst anterior horn.

   

• Whilst a tear is not seen extending to the articular margin, the presence of the cyst indicates an underlying meniscal tear.

WHAT ARE THE FINDINGS?

Linear high signal extending from the inferior to superior articular surface (Pink arrows) of the posterior horn medial meniscus.

WHAT'S THE Dx?

VERTICAL (LONGITUDINAL) MENISCUS TEAR POSTERIOR HORN

• The high signal extends to both the superior and inferior articular margins of the meniscus indicating a tear.

• It can be easy to overlook peripheral vertical tears as the torn outer fragment (Green arrows) can be very thin and may not be interpreted correctly as torn meniscus.

• Look for tissue that is the same signal as the parent meniscus and also irregularity of the residual meniscus margin which is torn.

WHAT ARE THE FINDINGS?

Displaced meniscal tissue (Pink arrows) deep to the superficial MCL (Green arrow).

WHAT'S THE Dx?

IS THE LATERAL MENISCUS TORN?

This is NOT a tear. The anterior horn of the lateral meniscus as it approaches its insertion into the tibia is normally fibrillated like this and this is a normal finding.