Pathophysiology
The most common causes for meniscal tears are trauma-related injury and degenerative disease (the latter more common in older patients).
In traumatic tears, the mechanism typically involves a young patient who has twisted their knee whilst it is flexed and weight-bearing, with the onset of symptoms following soon after.
There are a number of types of meniscal tears. The most common type of tear is a longitudinal tear – often termed a ‘bucket-handle’ tear – whereby the central tear becomes separated from the lateral fragment.
- Vertical
- Longitudinal(Bucket-Handle)
- Transverse(Parrot-Beak)
- Degenerative
Clinical significance
Injury[edit]
Main article: Tear of meniscus
Scar from partial left menisectomy in 1980 (c. 30 years before photo); more recent surgery leaves smaller scars.
In sports and orthopedics, people sometimes speak of "torn cartilage" and will actually be referring to an injury to one of the menisci. There are two general types of meniscus injuries: acute tears that are often the result of trauma or a sports injury and chronic or wear-and-tear type tears. Acute tears have many different shapes (vertical, horizontal, radial, oblique, complex) and sizes. They are often treated with surgical repair depending upon the patient's age as they rarely heal on their own. Chronic tears are treated symptomatically: physical therapy with or without the addition of injections and anti-inflammatory medications. If the tear causes continued pain, swelling, or knee dysfunction, then the tear can be removed or repaired surgically. The unhappy triad is a set of commonly co-occurring knee injuries which includes injury to the medial meniscus.