The meniscus is a specialized structure within the knee, and consist of a medial meniscus and lateral meniscus . They are crescent-shaped shock absorbers between the tibia and femur, and have an important role in the function and health of the knee. The menisci (plural) were once thought to be of little use. In fact, they were routinely removed when torn. However, we now know that the menisci contribute to a healthy knee. They play important roles in joint stability, force transmission, and lubrication.
What does the meniscus do?
The meniscus acts as a shock absorber for the knee. It spreads compression forces from the femur over a wider area on the tibia. Below are some of the functions of the meniscus:
The medial meniscus bears up to 50% of the weight applied to the medial (inside) compartment of the knee.
The lateral meniscus absorbs up to 80% of the weight on the lateral (outside) compartment of the knee.
During the various phases of walking, forces shift from one meniscus to the other. These forces on the knee can increase to 2 - 4 times your body weight.
While running, these forces on the knee can increase up to to 6 - 8 times your body weight! There are even higher forces when landing from a jump.
What is a meniscus injury?
An acute tear usually occurs when the knee is bent and forcefully twisted, while the leg is in a weight bearing position. Statistics estimate that about 61 of 100,000 people experience an acute tear of the meniscus.
Meniscal tears can be described in a variety of ways. Knowing where and how a meniscus was torn helps your doctor determine the best treatment.