Meniscal tears are the failure of the fibrocartilaginous menisci of the knee. There are several types and can occur in an acute or chronic setting. Meniscal tears are best evaluated with MRI.

Acute meniscal tears occur after rotatory trauma of the knee, whereas chronic degenerative meniscal tears often occur in the elderly after minimal rotatory trauma or stress on the knee. 

In older adults attritional changes in the meniscus lead to fragmentation of the meniscus and a variety of tears (there usually occur at the posterior horn of the medial meniscus) 8

There are different types of meniscal tears, describing the morphology of the injury. Identifying and accurately describing the type of meniscal tear can help the surgeon in patient education and planning of the surgical procedure. Meniscal tear types include 1,5,6:

On plain radiographs meniscal tears are not visible. In rare cases secondary signs can be seen, such as a soft tissue swelling next to the meniscus when a meniscal cyst is present 4. Only when associated with more complex injuries plain film may suggest a meniscal tear, e.g. arcuate sign, reverse Segond fracture, tibial plateau fracture. 

With a sensitivity of ~95% and a specificity of 81% for medial meniscal tears and a sensitivity of ~85% and a specificity of 93% for lateral meniscal tears 2,5, MRI is the modality of choice when a meniscal tear is suspected, with sagittal images being the most sensitive 5.

There are three basic MR characteristics/criteria of meniscal tears 5:

  • high intrameniscal signal extending to at least one (if not both) articular surfaces
  • which should be seen in at least two slices- two slice touch rule  (do not have to be contiguous, e.g. sagittal and coronal slices)
  • distortion of the normal meniscal morphology if no prior surgery

Each type of meniscal tear has its own characteristics on MRI, but in most cases the following can be seen 3:

  • T1: a hyperintense line in the meniscus can be seen, but it is difficult to differentiate between degeneration and meniscal tear on this sequence; in the case of a bucket-handle tear an empty groove can sometimes be seen
  • T2: a hyperintense line in the meniscus, which indicates synovial fluid in the meniscus
    • high T2 signal in mid substance of the meniscus without extension to the surface is not necessary a tear and can be:
      • in adult: secondary to degeneration 
      • in children: high vascularity of meniscus

See: MRI grading system for meniscal signal intensity.

Associated features that are suggestive of a meniscal tear include 5:

Surgical arthroscopy is done in most of the cases. Meniscopexy or complete or partial meniscectomy can be performed, depending on the degree and type of meniscal tear.

The differential can be variable dependent on the type of tear but in general consider. 

Knee pathology

The knee is a complex synovial joint that can be affected by a range of pathologies:

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Article information

rID: 32943
Section: Pathology
Synonyms or Alternate Spellings:
  • Meniscal tears
  • Meniscus tear
  • Meniscus tears

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Cases and figures

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    Case 1: radial tear
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    Case 2: posterior horn - longitudinal tear
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    Longitudinal Tear
    Case 3: posterior horn - longitudinal tear
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    Case 4: radial and horizontal tear
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    Case 5: root tear
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    Case 6: parrot beak tear
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    Case 6: posterior root tear
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    Case 7: bucket handle tear
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