Because the menisci bear a large proportion of stress during movement, they are prone to injury. Acute tears most often occur during a twisting motion, specifically when someone has planted their foot, flexed their knee, and then rotated. This type of motion causes a shearing force on the meniscus that results in a tear. Acute injuries commonly occur in sports, such as soccer, football, and basketball.
Symptoms associated with acute menisci tears depend on the extent of the injury. Generally, people are able to walk immediately after the injury and feel a variable degree of pain. Over the next 24 hours, they may experience swelling and an increase in pain. People with larger acute tears may experience more significant pain and have more limited knee motion. Acute, untreated meniscus tears are associated with developing osteoarthritis, a degenerative condition.
Degenerative meniscus tears often occur in older and middle-aged people. These may not be associated with an acute injury but rather repetitive forces on a weakened meniscus over time. Degenerative meniscus tears can also be associated with osteoarthritis. Osteoarthritis is caused by overuse of joints resulting in degeneration of that joint. It can cause weak menisci that are prone to tears.
Meniscus tears are described by the type of tear.
These descriptions help surgeons plan their treatment approach and predict success.
Tears can be described as vertical longitudinal, transverse, oblique, horizontal, meniscal root, bucket-handle, or complex.
They are also described by the avascular (white) or vascular (red) zone. The vascular zone refers to the blood vessels that supply that area of the meniscus and thus the healing potential. Generally, a better blood supply corresponds with better healing. The red zone has the best blood supply while the white zone has a poor blood supply. Repair of a meniscus in the setting of an ACL reconstruction also tends to lead to a more successful repair.
Dr. Morton will decide how to treat your tear during surgery based on the potential for your tear to heal. Tears on the outside of the knee are less likely to heal. If he does not feel that it will heal, he will remove it. If there is a possibility of repair, he will offer this option to you.