The meniscus is the horizontal “cushion,” or cartilage pad, between the upper bone (femur) and lower bone (tibia). The one on the inner side of the knee is the medial meniscus. The lateral meniscus is on the outer side of the knee.

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A meniscus tear, one of the most common knee injuries, can be the result of osteoarthritis-related degeneration, an injury caused by twisting or a sudden stop, or a blow to the knee. The risk increases with age, being overweight, or both.

The meniscus is a crescent-shaped cartilage pad between the femur (the bone in the upper leg) and the tibia (a long bone in the lower leg). There are two menisci: one on the inside of the knee (the medial meniscus) and the other on the outside (lateral meniscus). They improve the fit between the two bones, act as a shock absorber, move lubricating fluid around the knee, and distribute the body’s load on the knee joint.

Pain, Swelling, Popping, Locking, Buckling

Symptoms of a meniscus tear usually begin with pain and swelling. The pain can be on the inner or outer side of the knee, not around the kneecap itself. Swelling often does not occur until the day after an injury, and swelling is not necessarily in the same area as the pain. A meniscus tear may also cause a popping sound, especially when going up or down stairs. A possible source of the sound is a piece of loose cartilage that gets caught as the knee joint moves.

A torn meniscus can cause catching or locking of the knee. The knee gets stuck in midrange for days at a time, and on occasion the patient can “unlock” the knee by gently bending or twisting it before trying to straighten it.

Some people with a torn meniscus can function more or less normally. Others find that it prevents them from participating comfortably in their normal daily activities. Some patients may feel that the knee is unstable; it may even buckle.

Meniscus Tear: Conservative vs. Invasive Treatment

To determine the precise nature of the injury, a doctor gets your medical history, performs a physical exam, and uses X-rays and/or magnetic resonance imaging (MRI). Self-management of a torn meniscus begins with over-the-counter medications, (ibuprofen, acetaminophen), rest, ice, compression, and elevation.

Knee strengthening exercises for the quadriceps and hamstrings can help a person return to normal function following an injury and perhaps prevent another tear. Examples: straight leg raises, wall squats, passive knee extension, heel raises, and step-ups. Check with a physician or physical therapist before beginning a new exercise program.

Surgery is an option, with as many as 750,000 procedures performed each year in the U.S. But recent research is not as supportive of meniscus surgery as it once was. It is a minimally invasive arthroscopic procedure in which the meniscus is repaired or removed.

Study #1: “Vast Majority” Do Not Need Surgery

In a May 2017 issue of BMJ, a panel of physical therapists, orthopaedic surgeons, other physicians, and patients conducted a review of meniscus-related studies. They concluded that arthroscopy—minimally invasive surgery—should not be performed on the vast majority of patients with degenerative knee disease, including those with a meniscus tear.

Degenerative knee disease was defined as knee pain not caused by traumatic injury in patients over age 35, with or without imaging evidence of osteoarthritis, meniscal tears, or mechanical symptoms.

Outcomes for knee arthroscopy were no better than exercise in people with degenerative meniscus tears. The panel added that further research would be unlikely to alter their recommendations.

Study #2: Exercise as Effective as Surgery

In 2016, BMJ reported on a study conducted in Norway and Denmark in which 140 meniscus tear patents drew lots for treatment with either exercise or surgery. After two years, both groups had fewer symptoms and better knee function, and there were no significant differences between the two groups in terms of outcomes.

Recovery time following a torn knee meniscus depends on the treatment—a month or so if conservative treatment works vs. up to three months if surgery is performed.

When Meniscus Tear Symptoms Persist

Although arthroscopically treating a torn meniscus may eliminate mechanical symptoms such as catching or locking, the symptoms of accompanying osteoarthritis—stiffness, achiness, pain—may persist. When that happens, the remaining options are 1) injections of corticosteroids or lubricating substances, and 2) partial or total knee replacement.

Injections are a temporary fix that have to be repeated periodically. Knee replacement is an effective but last-resort approach that might be recommended for severe knee osteoarthritis, not simply a torn meniscus.