A meniscus is a piece of c-shaped cartilage that functions as a shock absorbing cushion between the femur (thigh bone) and tibia (shin bone). Each knee joint has two menisci – medial and lateral. These pieces of tissue provide structural integrity to the knee when it undergoes any type of loading or twisting maneuver and helps to disperse load appropriately across the joint. Without a meniscus, there is an increased risk of arthritis that may develop over time.
There are two common types of meniscal injuries: acute injuries due to traumatic or sports-related events and chronic injuries such as degenerative processes or wear and tear that commonly occurs as one ages. The risk of developing a chronic or degenerative meniscal tear increases with age. This is due in part to the fact that the integrity of the meniscus tissue becomes less resilient with age. Meniscus tears that are acute or traumatic can occur in isolation or in association with other ligament injuries (i.e., an ACL tear).
It is important to understand that chronic meniscus tears occur over time and in many cases are simply incidental findings on MRI. Emphasizing a patient’s goal of achieving less pain and more function rather than “healing” the tear is the mainstay of initial treatment, especially for long-standing tears. There is no conclusive data that living with and remaining active with a chronic meniscus tear will in effect make them worse. Related to this decision-making is the fact that patients who have arthritis commonly have an associated chronic meniscus tear.
When considering surgical intervention, patients must be educated to the fact that both conditions can become a source of pain and surgical treatment for arthritis with arthroscopy (below) can be of limited value in terms of completely reducing a patient’s symptoms for a significant period of time when the arthritic changes are the primary pain generator.
Symptoms related to a meniscal tear may include but are not limited to: swelling, mechanical sensations such as locking or catching and on occasion, limited range of motion of the knee joint. Understanding a patient’s symptoms including the length of time present and functional limitations helps to aid in the decision-making process for treatment. The diagnosis of a meniscus tear is obtained through obtaining a patient’s history, performing a physical examination and occasionally, an MRI.
After proper diagnosis, an appropriate treatment plan can be created. An initial diagnosis of a meniscus tear does not necessarily mean surgical treatment is imminent or immediate. Treatment of a meniscus tear depends on a few different factors including tear configuration, the length of time the tear has been present in the knee, the activity level of the individual, and the initial response to simple conservative treatment measures. Meniscus tears do not typically repair or heal by themselves; however, reductions in pain and return to normal activities without limitations can be obtained through conservative management for some individuals with certain tear patterns.
Conservative measures for reducing of pain, swelling and return of function can be very effective and includes such things as anti-inflammatories, cortisone injections and physical therapy. One would expect to see improvement in a patient’s symptoms within 2-3 weeks after engaging in a course of conservative management. If conservative measures are not an option (for example, with a traumatically induced large displaced meniscus tear that blocks knee motion) and/or they have failed to help manage symptoms, then surgical intervention may be necessary.
If surgery becomes necessary, it is performed arthroscopically where a camera is introduced into the joint through small incisions to visualize the structures inside the knee. This is an outpatient procedure that takes around 25-30 minutes. At the time of arthroscopy, the meniscus tear is either trimmed back to a stable edge (meniscectomy) or repaired with stitches (meniscus repair). Whenever possible, large tears that are considered repairable should be fixed because it may reduce the chance of arthritis developing in the future.
Repair of a meniscus is performed when the tear pattern allows it to be fixed and when there is an appropriate blood supply at the site of the tear, which will lead to a higher incidence of healing. Return to high-level activities following a meniscus repair can take as long as 4 to 6 months. There is however, a risk of re-tear especially when tears occur and are repaired in isolation (i.e., without a concomitant ACL tear) that approaches 25% in some published reports. Thus, the decision-making is rather complex and individualized to the patient.
Alternatively, return to high-level activity following a simple meniscectomy takes on average 4-6 weeks after the surgical intervention. Weight-bearing immediately post operatively is encouraged unless otherwise directed by the surgeon. Engaging in post operative physical therapy can also aid in one’s recovery and return to full activities.