The meniscus is a C-shaped structure located between the femur and tibia. One meniscus is on the inside of the knee, and another is on the outside. The meniscus is made of a type of cartilage that helps it serve as a shock absorber to the knee.
Meniscal tear causes
In younger athletes, injury to the meniscus typically requires a traumatic event. Usually a combination of joint compression and twisting is required to tear the meniscus. Often the injury occurs in combination to other knee injuries, such as a torn ACL. As people age, less force is needed to tear the meniscus due to degenerative changes in the meniscus. An adult patient might not even remember an injury that caused the pain.
Signs and symptoms of a meniscal tear
The complaints of younger athletes with a torn meniscus often differ from older patients. Younger patients usually note significant pain soon after a twisting injury from sports or other trauma. Typically the pain is localized to a specific point on the inside or outside of the knee, often associated with a locking or catching sensation. The knee feels stuck in a position and must be moved around to unlock. Occasionally an athlete is unable to move the knee out of a certain position. In this case, the meniscus often has torn and flipped into the center of the knee, preventing motion.
In older patients, the complaints can be much less specific, including pain without locking or catching sensations. The pain still is fairly localized, especially to the inside and back of the knee. Swelling of the knee is occasionally noted. Since degenerative meniscal tears can be present in patients with pre-existing arthritis, the patient may complain of a sharp increase in pain from the dull, aching pain experienced for years.
Diagnosing a meniscal tear
It is reasonable to seek medical evaluation if symptoms do not improve with conservative measures, such as rest and avoiding aggravating activities, compression, ice, and elevation. An MUSC Health sports medicine surgeon performs a thorough history and physical examination, and, in many cases, can detect tenderness in a specific location along the joint line. Provocative tests to recreate the pain with a combination of knee flexion and tibial rotation can elicit the pain as well. X-rays can rule out other joint problems and determine the presence of arthritis in older patients. Because the meniscus cannot be seen on the X-rays, an MRI might be necessary to confirm the diagnosis.
Typically a meniscus tear does not heal on its own. Younger athletes, especially those with a locked knee, almost always need surgery in order to resume cutting and pivoting sports. The decision for older individuals is not always clear. In the setting of significant arthritis and a degenerative meniscus tear, surgery is not always the first, or best, option. Pain from the torn meniscus usually improves dramatically with arthroscopic surgery. But arthritis, which is the breakdown of the articular cartilage on the ends of the bones, often does not greatly improve after cleaning up the damaged cartilage. Knowing how much of the pain is meniscal in origin, and therefore predicting how much relief a patient will achieve, can be difficult. Treatment options can be discussed in detail with an MUSC Health surgeon.
Surgical treatment of a torn meniscus involves arthroscopic surgery, or using a small scope to look throughout the knee and treat any problems found. In most cases, the meniscus tear can be treated in one of two ways. In most cases, trimming out the torn section of meniscus will remove the part that is catching inside the knee and causing pain while preserving the majority of the tissue for shock absorption. In some cases, especially those involving younger patients, the meniscus often can be repaired or sewn back together with stitches. Whether or not a meniscus can be repaired depends on factors such as location, size, and orientation of the tear. In many instances it is difficult to predict whether the tear is repairable without arthroscopy. In most cases, if the surgery involves trimming out the torn section of meniscus, few restrictions are placed on the patient after surgery. He or she can bear weight as tolerated and slowly work back toward normal activities. A meniscus repair needs to be protected in order to increase the likelihood that it will heal, so many surgeons will restrict weight bearing and motion of the knee for the first few weeks after surgery.