A meniscus is a C-shaped structure that is made out of a strong rubbery material termed fibrocartilage. Each knee has two menisci. These menisci reside between the femur (thigh bone) and the tibia (main bone in lower leg).
The main functions of a meniscus include shock absorption and load transmission. The secondary functions of a meniscus include joint stability, lubrication and nutrition.
In middle-aged and elderly people, meniscus tears are usually related to the normal age-related weakening and degeneration that the menisci undergo. Hence, a minor twist or fall can cause meniscus tears in these age populations.
In younger age populations, a more forceful injury event is usually required to cause a meniscus tear. A common mechanism of injury is a forceful twisting or rotation of the knee while the person’s full weight is born through that leg. Other mechanisms of injury can be jumps, jump landings and direct blows to the knee. All of these mechanisms of injury are seen in numerous sports.