The anterior cruciate ligament (ACL) is one of the major ligaments of the knee. It is located in the middle of the knee and runs from the femur (thighbone) to the tibia (shinbone).
A meniscal tear is a common knee injury in athletes, especially those involved in contact sports. A sudden bend or twist in your knee causes the meniscus to tear. Elderly people are more prone to degenerative meniscal tears as the cartilage wears out and weakens with age.
Articular cartilage does not have a direct blood supply to it so has little capacity to repair itself. Once the cartilage is torn it will not heal easily and can lead to degeneration of the articular surface, leading to the development of osteoarthritis.