Tears can lead to pain and/or swelling of the knee joint. Especially acute injuries (typically in younger, more active patients) can lead to displaced tears which can cause mechanical symptoms such as clicking, catching, or locking during motion of the knee joint. The joint will be in pain when in use, but when there is no load, the pain goes away.
The patient can sometimes remember a specific activity during which the injury was sustained. A tear of the meniscus commonly follows a trauma which involves rotation of the knee while it was slightly bent. These maneuvers also excite the pain after the injury; for example, getting out of a car is often reported as painful.
After noting symptoms, a physician can perform clinical tests to determine if the pain is caused by compression and impingement of a torn meniscus. The knee is examined for swelling. In meniscal tears, pressing on the joint line on the affected side typically produces tenderness. The McMurray test involves pressing on the joint line while stressing the meniscus (using flexion-extension movements and varus or valgus stress). Similar tests are the Steinmann test (with the patient sitting) and the Appley test (a grinding maneuver while the patient lies prone and the knee is bent 90°). Bending the knee (into hyperflexion if tolerable), and especially squatting, is typically a painful maneuver if the meniscus is torn. The range of motion of the joint is often restricted.
The Cooper's Sign is present in over 92% of tears. It is a subjective symptom of pain in the affected knee when turning over in bed at night. Osteoarthritic pain is present with weightbearing, but the meniscal tear causes pain with a twisting motion of the knee as the meniscal fragment gets pinched, and the capsular attachment gets stretched causing the complaint of pain.
Also see: Bounce Home Test, Thessally's Test, Wilson's Test (internal/external rotation), and Bohler's Test.
The treatment course is dependent on the needs and status of the patient. A conservative course of treatment involving just physical therapy is possible. The patient will probably have to take a small break from his or her normal activities, allowing the knee to heal. Exercises can strengthen the muscles around the knee, especially the quadriceps. Stronger and bigger muscles will protect the meniscus cartilage by absorbing a part of the weight. The patient may be given paracetamol or anti-inflammatory medications.
If this does not resolve the symptoms or in cases of a locked knee, then surgical intervention may be required. Depending on the location of the tear, a repair may be possible. In the outer third of the meniscus, an adequate blood supply exists and a repair will likely heal. Usually younger patients are more resilient and react well to this treatment, while older, more sedentary patients do not have a favorable outcome after a repair.
The meniscus has fewer vessels and blood flow towards the unattached, thin interior edge. In the majority of cases, the tear is far away from the meniscus' blood supply, and a repair is unlikely to heal. In these cases arthroscopic surgery allows for a partial meniscectomy, removing the torn tissue and allowing the knee to function with some of the meniscus missing. In situations where the meniscus is damaged beyond repair or partial removal, a total menisectomy is performed. This option is avoided at all costs as total meniscectomy leads to an increased risk of osteoarthritis (with loss of cartilage) and eventual total knee replacement. In some cases, a meniscus replacement is done to prevent this.
Recently, transplants of full meniscus are accomplished successfully regularly, although it is still somewhat of a rare procedure and many questions surrounding its use remain.
If the destroyed part of the meniscus was removed, patients can usually start walking a day or two after surgery. Although each case is different, patients return to their normal activities on average after a few weeks (2 or 3).
If the meniscus was repaired the rehabilitation program that follows is a lot more intensive. After the surgery a hinged knee brace is placed on the patient. This brace allows controlled movement of the knee. The patient is encouraged to walk using crutches from the first day, and most of the times can put weight on the knee. The time course varies with each patient, but roughly after four weeks the patient can start walking using the hinged knee brace only. Starting from the second month the patient can walk freely and can also do various "light" exercises (static bicycle, swimming, etc.). If the rehabilitation was done properly the patient can gradually return back to "heavier" activities (like running).