University of Virginia Health System

By David R. Diduch, M.D.

What Is The Meniscus?
The meniscus is a semicircular, C-shaped structure that occupies the space between the thigh bone and the shin bone in the knee. There is one on either side of the knee: the medial meniscus on the inner side, and the lateral meniscus on the outer side. The meniscus is a firm, rubbery type of cartilage that functions as an important shock absorber between the bones and provides some stability to the knee.

How Does It Tear?
Sometimes the meniscus can be torn resulting in knee pain. Tears of the meniscus generally present in two very different ways. One is a sudden, traumatic event during which a person knows they have done damage to their knee. The knee becomes moderately swollen, and they have difficulty trying to perform work or sporting activities. Symptoms may improve over several days, but are easily reaggrevated with twisting, squatting or jumping motions. This type of tear may also be associated with torn ligaments such as the anterior cruciate ligament. The other type of tear is a degenerative tear in which the meniscus softens and weakens as part of a normal aging process. The actual tear occurs with relatively minor trauma, such as getting in and out of a chair or a car. The person is generally unaware when this happened, but notes that for the past several months, the knee intermittently swells and catches, with pain usually in the back or side of the knee.

Do I Need Surgery?
While not all meniscal tears require surgery, those that are symptomatic generally do. Meniscal tear symptoms are intermittent pain and swelling, catching, giving way, inability to fully straighten the knee, or difficulty squatting or twisting. The torn meniscus fragment can move and get pinched between the bones in the knee, causing secondary erosion of the joint surface, resulting in arthritis. For that reason, symptomatic meniscal tears should be taken care of by surgery.

Arthroscopic Surgery
Arthroscopic surgery is very effective at treating meniscal tears. Through small puncture wounds in the front of the knee, an orthopaedic surgeon can visualize the meniscus as well as the joint surface and ligaments quite well. Small instruments are used to remove or repair the torn fragments, so that they no longer are pinched between the bones. Arthroscopy takes an average thirty minutes and is an outpatient procedure with a recovery of a few days for deskwork, to a few weeks for heavy labor. Patients can usually return to sports, including running, within three to six weeks unless other structures are also injured within the knee.