The meniscus is a C-shaped piece of cartilage that provides a cushion between your thighbone (femur) and shinbone (tibia). There are two menisci in each knee joint – one at the outer edge of the knee and the other at the inner edge. The menisci keep the knee steady by balancing body weight across the knee. A torn meniscus can prevent the knee from working correctly.
Menisci tear in different ways. Tears are noted by how they look, as well as where the tear occurs in the meniscus. Common tears include longitudinal, parrot-beak, flap, bucket handle and mixed/complex.
Causes
Sudden meniscal tears often happen during sports. Athletes, particularly those who play contact sports, are at risk for meniscal tears. However, people of all ages can tear a meniscus. Aged, worn tissue is more prone to tears. In older adults, the meniscus can be damaged following prolonged ‘wear and tear’ called a degenerative tear. Just an awkward twist when getting up from a chair may be enough to cause a tear, if the menisci have weakened with age.
The meniscus can be torn by traumatic force encountered during physical exertion. The traumatic action is most often a twisting movement at the knee while the leg is bent. Any activity that causes a forceful twist or rotation of the knee, especially when putting the pressure of whole body weight on it, can lead to a torn meniscus. In addition, the meniscus can be torn during innocuous activities such as walking or squatting.
Symptoms
Individuals with a torn meniscus may experience the following signs and symptoms in the knee:
- A popping sensation
- Pain, especially when twisting or rotating the knee
- Stiffness and swelling
- Catching or locking of the knee
- Difficulty straightening the knee fully
- The sensation of the knee “giving way”
- Not able to move the knee through its full range of motion
Without treatment, a piece of meniscus may come loose and drift into the joint. This can cause the knee to slip, pop or lock.