• Introduction
  • Meniscus Injury

    Frequency and Types of Meniscus Tear

    Meniscus Injury – A Common Occurrence

    What is the meniscus?  A meniscus is a roughly circular pad of very tough cartilage located in the knee between the top of the tibia (shin) and the bottom of the femur (thigh). There are two menisci in each knee. They are shaped like wedges, with the thicker portion of the wedge on the outside of the circular shape and the thinner portion towards the inside. The purpose of the menisci is to cushion and stabilize the knee.

    If your surgeon has told you that you may need knee meniscus surgery, you’re not alone. There are an estimated 850,000 such surgeries performed annually in the US1.  Meniscus tears are among the most common knee injuries, especially from twisting injuries with the foot in a fixed position. Aging, falls and other accidents, and participation in athletics are just some of the causes of meniscus tears. Tears occur in either the horizontal or vertical direction, or a combination of both. A meniscus tear is also often designated as medial or lateral. “Medial” refers to the portion of the knee toward the midline of the body, the inside portion of the knee between the legs. “Lateral” refers to the outside portion of the knee, away from the midline of the body.


    Reasons for Meniscus Surgery

    diagram of a torn meniscusOnce the meniscus tear is found, your doctor may recommend the option of conservative treatment, including rest, ice, and non-steroidal anti-inflammatory drugs. An MRI of the knee may be ordered to assist in evaluating the tear. Some tears may improve slowly, and so your doctor may or may not recommend surgery
    (see surgeon opinions about who can and can’t wait for meniscus tear surgery)
    (see surgeon opinions about proper meniscus tear diagnosis in primary care)

    Although the goal of meniscus surgery is to preserve healthy meniscus tissue, many types of tears are not repairable, and so injured tissue must be removed. In order to heal, a meniscus tear requires a blood supply. Blood flow to the inner portions of a meniscus is limited compared to the peripheral or outer portions, suggesting why tears of the inner meniscus may not heal as well and may not respond to conservative treatment.

    If surgery is recommended, your doctor will determine to either remove the torn tissue or repair it. This decision is based on age, where the tear is located within the meniscus and its severity. Because of a lack blood flow required for healing, tears located more towards the middle of the meniscus are removed, while tears towards the outside can sometimes, but not always, be repaired. Indications for surgery include frequency of symptoms, degree of pain and/or impaired knee function and the type of tear (e.g., complex tear).
    (see surgeon opinions on realistic expectations for meniscus tear treatment)
    (see surgeon opinions about impact of arthritis on success of meniscus surgery)