Meniscus tears are among the most common knee injuries. There are two menisci in your knee; each rests between the thigh bone (femur) and shin bone (tibia). The menisci are made of tough cartilage and conform to the surfaces of the bones upon which they rest. One meniscus (the medial meniscus) is on the inside of your knee. The other meniscus (the lateral meniscus) rests on the outside of your knee.
The meniscus functions to distribute your body weight across the knee joint. Without the meniscus present, the weight of your body would be unevenly applied to the bones in your legs (the femur and tibia). This uneven weight distribution may cause excessive forces in specific areas of bone, potentially leading to early arthritic changes of the knee joint. Therefore, the function of the meniscus is critical to the health of your knee.
The two most common causes of a meniscus tear are traumatic injury (often seen in athletes) and degenerative processes (seen in older patients who have more brittle cartilage). The most common mechanism of a traumatic meniscus tear occurs when the knee joint is bent and the knee is then twisted. It is not uncommon for the meniscus tear to occur along with injuries to the anterior cruciate ligament (ACL) and the medial collateral ligament (MCL) these three problems occurring together are known as the “unhappy triad.”
Symptoms of a meniscus tear include:
- Knee pain
- Swelling of the knee
- Tenderness when pressing on the meniscus
- Popping or clicking within the knee
- Limited motion of the knee joint
A history and physical exam along with an MRI may be needed to determine whether or not a patient has a meniscus tear.