The two menisci cushion the space between femur and tibia.
A longitudinal tear of the meniscus.
Classical pose that may cause meniscus injury - foot planted and body twisted with force.
Torn meniscus symptoms
Usually the patient with a torn meniscus remembers:
- an injury that involved a twisting motion, commonly a twist of the body with the foot planted on the ground, like a footballer kicking.
- an audible noise at the time of injury
- the knee may swell with blood soon after the injury.
- Once the acute situation settles, the patient my have pain in the joint line and feelings of instability of the knee.
Medial or lateral meniscus tear - which is worse?
Lateral meniscus tears are less common than medial meniscus tears, and the outcomes are different. Lateral tears tend to have a worse outcome because:
- the lateral meniscus absorbs about 70% of the shock going through the joint.
- the lateral meniscus is more mobile as there is less connection to the top of the tibia bone. There is actually a big gap where the popliteus tendon runs. Normally this is no problem, but tears running into this gap can reduce even further the connection to the tibia and this may significantly increase knee instability.
Will a torn meniscus heal without surgery?
Healing of a tear in the meniscus without surgery will depend upon a number of factors:
- the shape of the tear - radial tears and horizontal cleavage tears heal poorly (if at all)
- how close the tear is to the inner rim - there is no blood supply in the inner rim. Tears close to the outer rim, where the blood supply is good, heal more efficiently (see cross-section of the meniscus on the right)
- the size of the tear - large tears may lead to more displacement of the edges, so they cannot heal. A 'bucket-handle' tear may have a displacement of the torn part right to the other side of the rounded condyle
How surgeons fix a torn meniscus
If the surgeon assesses the meniscus tear and feels that it is in the patient's best interest to repair it, he/she can use sutures (stitches) or small devices shot through the torn edges and hold the edges together until healing occurs - this is called meniscal repair. If the tear is close to the inner edge where blood supply is poor, a simple meniscal trim may prevent further deterioration. If it is not feasible to repair a large tear, the surgeon may perform a partial meniscectomy or in desperate cases even a total meniscectomy.
Treatment of meniscal tears: An evidence based approach. Mordecai SC, Al-Hadithy N, Ware HE and Gupte CM. World J Orthop. 2014 Jul 18; 5(3): 233–241.
Natural history and clinical significance of meniscal tears over 8 years in a midlife cohort. Khan HI, Aitken D, Ding C, Blizzard L, Pelletier J-P, Martel-Pelletier J, Cicuttini F and Jones G. BMC Musculoskelet Disord. 2016; 17: 4.
Modern treatment of meniscal tears. Doral MN, Bilge O, Huri G, Turhan E and Verdonk R. EFORT Open Rev. 2018 May; 3(5): 260–268.
See also -
- Radial tear
- Longitudinal tear
- Bucket-handle tear
- Horizontal cleavage tear
- Parrot-beak tear
- Flap tear
Professor Adrian Wilson examines a patient with a torn medial meniscus.
Video of a meniscal trim, courtesy of Dr Ram Venkatesh