Meniscal tears are among the most common knee injuries. Athletes, particularly those who play contact sports, are at risk for meniscal tears. However, anyone at any age can tear a meniscus.
When people talk about torn cartilage in the knee, they are usually referring to a torn meniscus. There are two menisci located in the knee joint between the femur (thigh bone) and the tibia (shin bone). The C-shaped medial meniscus is on the inside part of the knee, while the U-shaped lateral meniscus is on the outer half of the knee joint. The meniscus act like shock absorbers in the knee, forming a gasket between the femur and tibia to help spread out the forces that are transmitted across the joint and keep it stable.
A meniscus tear is usually the result of either a traumatic incident or degeneration. The meniscus receives very little blood flow (only to the outer 1/3 of the meniscus), which makes recovery extremely difficult. Additionally, the cartilage that makes up the menisci weakens and wears thin over time. In younger people, the meniscus is a fairly tough and rubbery structure. Tears in the meniscus in patients under 30 years old usually occur as a result of a forceful twisting or sudden impact injury, commonly sustained during sport activities. Older individuals are more likely to have degenerative meniscal tears, as aged and worn tissue is more prone to tears.
Conservative treatment for a torn meniscus focuses on decreasing pain and swelling in the knee, as well as regaining normal movement of the joints and muscles. This treatment is especially effective when the tear occurs on the outer edge of the meniscus, which does receive a blood supply. However, surgery to trim away the torn cartilage may be recommended if the knee locks up and normal movement is not restored through conservative methods.