Meniscus Injuries Workup

Updated: Oct 12, 2018
  • Author: Bradley S Baker, MD; Chief Editor: Craig C Young, MD  more...
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Workup

Imaging Studies

See the list below:

  • Plain radiography: An anteroposterior weight-bearing view, posteroanterior 45º flexed view, lateral view, and Merchant patellar view should be obtained to rule out degenerative joint changes (arthritis) or fractures.

  • Arthrography: Historically, arthrography was the standard imaging study for meniscal tears, but it has been replaced by magnetic resonance imaging (MRI).

  • MRI: This is the criterion standard imaging study for imaging meniscus pathology and all intra-articular disorders. [14, 15]

    • Normal menisci have a homogeneous low signal. Abnormal meniscal signals are classified into the following 3 groups:

      • Grade I – Small area of increased signal within the meniscus

      • Grade II – Linear area of increased signal that does not extend to an articulating surface

      • Grade III – Abnormal increased signal that reaches the surface or edge of the meniscus

    • Grade I and II changes are common in older patients as evidence of the normal aging degenerative process and in young patients as normal perforating vascular channels. Grade I and II changes are not usually seen arthroscopically and do not represent meniscal tears. Grade III changes are meniscal tears.

    • MRI has proven to be an effective technique for evaluating menisci.

      • Average sensitivity – 95% medial, 81% lateral

      • Average specificity – 88% medial, 96% lateral

      • Average accuracy – 92% medial, 92% lateral

    • Meniscal root tears are directly or indirectly diagnosed by MRI by assessing the amount of meniscal extrusion, defined as at least 3 mm of coronal translation beyond the margin of the tibia. [1, 16]

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Procedures

See the list below:

  • Arthroscopy

    • In the hands of a competent arthroscopist, arthroscopy is considered the best tool for meniscal tear diagnosis, with sensitivity, specificity, and accuracy approaching 100%.

    • Arthroscopy is therapeutic and diagnostic and thus offers the advantage of immediate treatment of most disorders. [15, 17, 18]

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