Meniscal tear
Updates to Article Attributes
Meniscal tears involve damage to the fibrocartilaginous menisci of the knee. They are several types and can occur in an acute or chronic setting. Meniscal tears are best evaluated with MRI.
Clinical presentation
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.
Types
There are different types of meniscal tears. 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:
- horizontal tear: parallel to the tibial plateau
- longitudinal tear: perpendicular to the tibial plateau; parallel to the long axis of the meniscus
- radial tear: perpendicular to the tibial plateau and the long axis of the meniscus
- root tear: often a radial-type tear
- complex tear: combination of all or some of horizontal, longitudinal and radial-type years
- displaced tear
- bucket-handle tear: longitudinal tear with medial displacement of the central fragment
Radiographic features
Plain film
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.
MRI
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 two basic MR characteristics of meniscal tears 5:
- high intrameniscal signal extending to at least one (if not both) articular surfaces on two slices (do not have to be contiguous, e.g. sagittal and coronal slices)
- distortion of the normal meniscal morphology
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: hyperintense line in the meniscus, which indicates synovial fluid in the meniscus
(See MRI grading system for meniscal signal intensity)
Associated features that are suggestive of a meniscal tear include 5:
- tibial subchondral bone oedema
- parameniscal cyst
Treatment and prognosis
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.
Differential diagnosis
-</ul><p>Associated features that are suggestive of a meniscal tear include <sup>5</sup>:</p><ul>- +</ul><p>(See <a title="MRI grading system for meniscal signal intensity" href="/articles/mri-grading-system-for-meniscal-signal-intensity">MRI grading system for meniscal signal intensity</a>)</p><p>Associated features that are suggestive of a meniscal tear include <sup>5</sup>:</p><ul>
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