from aaos.org

The image at left reveals a normal meniscus sitting between the femur above and the tibia below. The meniscus is a C-shaped structure in your knee that is made of fibro-cartilage. It acts as a cushion for the knee when it’s bearing weight.

Most meniscal tears in adults are attritional

that is, the meniscus simply wears out from years of use. Most adult patients with a torn meniscus don’t even recall how or when the meniscus tear happened.

The presentation for a meniscus tear is usually quite different in children or adolescents. Their tears are usually traumatic in nature and will usually arise from a non-contact twisting injury.