The menisci are two circular strips of cartilage that form a cushioning layer between the ends of the femur (thigh bone) and tibia (shin bone) in the knee joint. Together the medial and lateral menisci, on the inside and outside of the knee, respectively, act as shock absorbers and distribute the weight of the body across the knee joint.

The menisci can become torn through injury or damaged from age-related wear and tear and may require surgery.

The most common meniscal surgery is partial meniscectomy in which the torn portion of the meniscus is cut away so that the cartilage surface is smooth again.
In some cases meniscal repair is carried out, in this case the torn edges of the meniscus are sutured together.
Both procedures are performed arthroscopically.

For more detail visit the AAOS website for meniscal tear information and for meniscal transplant surgery.