A torn meniscus (or meniscus tear) is an injury that can occur when some activity or injury forces an individual to rigorously twist or rotate the knee, especially when simultaneously putting full body weight on the knee and the knee is bent. This combination of stress can result in a torn meniscus, and it is common among athletes. When athletes say they have torn their cartilage, what they have really done is torn their meniscus. These two terms are often used interchangeably. In older adults, arthritis changes in the knee may contribute to a meniscus tear because their cartilage is more brittle. In these cases, no direct injury is usually involved.
A meniscus tear often occurs along with injuries to the anterior cruciate ligament (ACL) and the medial collateral ligament (MCL). This combination of knee injuries in seen in sports such as football in which players are hit on the outside of the knee.
Symptoms of a meniscus tear include knee pain, swelling of the knee, tenderness when pressing on the meniscus, clicking or popping within the knee joint, and limited movement of the knee joint. Some people also experience joint locking, which is an inability to completely straighten the knee.