What Is It?

A meniscus is a disk-shaped piece of cartilage that acts as a shock absorber inside a joint. Each knee has one lateral meniscus under the outer knob of the thighbone and one medial meniscus under the inner knob of the thighbone. Each meniscus acts as a natural cushion between the thighbone (femur) and shinbone (tibia). The two cushions prevent excess wear and tear inside the knee joint by keeping the ends of the two bones from rubbing together. Each meniscus also absorbs much of the shock of jumps and landings, and helps to distribute joint fluid evenly to lubricate and nourish the knee.

In the United States, a torn meniscus is the most common reason for knee surgery. In 1996 alone, treatment for a torn meniscus accounted for more than 250,000 clinic visits to U.S. medical centers.

The symptoms of a torn meniscus can include:

• Knee pain, usually on one side of your knee
• Tenderness at the side of the joint
• Knee swelling within the first 12 hours after injury
• A “locked” knee that can’t be bent
• A knee that catches during movement, or can’t be fully straightened
• A click, pop or grinding inside your knee when you move it
• A knee that buckles, gives way or feels generally weak

Your doctor will inspect both your knees to compare your injured knee with your uninjured one. He or she will check your injured knee for signs of swelling, tenderness and fluid inside the knee joint. If your knee is not locked, the doctor will bend your injured knee and check for clicks, snaps and “catches” within the joint. Your doctor also will also evaluate your knee’s range of motion and will maneuver your knee to see whether your meniscus is sensitive to pressure. For example, in the “McMurray test,” the doctor bends the leg at the knee, and then rotates it inward or outward while straightening it. If you feel pain during this test or there is a “click” sound as your leg rotates, there is a good chance that your meniscus is torn.

If the results of your exam suggest you have a torn meniscus, you may need tests to further evaluate your knee. Tests may include:

• Knee X-rays to check for bone injuries, including fracture, that can cause symptoms similar to a torn meniscus
• A magnetic resonance imaging (MRI) scan or computed tomography (CT) scan — Nine out of 10 times, a torn meniscus will show up on one of these tests.
• Arthroscopy (camera-guided surgery) to look inside the knee joint and examine the meniscus — When arthroscopy is used for diagnosis, the problem can be treated during the same surgery.

If you have arthroscopic surgery to treat your torn meniscus, and your job involves sedentary work (mostly sitting), you may be able to return to work one to two weeks after surgery, with full recovery in about four to eight weeks. If you are an athlete, or your job requires a lot of physical activity, it may take three to four months after surgery before you feel like you have as much function in your knee as you require.

Although it’s hard to prevent accidental knee injuries, you may be able to reduce your risks by:

• Warming up and stretching before participating in athletic activities
• Exercising to strengthen the muscles around your knee
• Avoiding sudden increases in the intensity of your training program
• Wearing comfortable, supportive shoes that fit your feet and your sport

There are several options for treating a torn meniscus:

• Nonsurgical — This may include a temporary knee brace and rehabilitation to keep the knee muscles strong while the knee is not bearing as much weight. This approach is most effective for small tears (5 millimeters or less) near the edge of the meniscus, where healing is usually good, or for people who are not good candidates for surgery.
• Surgery to repair the tear — If the tear is large (1 to 2 centimeters), but it involves a portion of the meniscus where blood supply is adequate for healing, the doctor may be able to repair it with stitches.
• Surgery to remove part of the meniscus (partial meniscectomy) — If the tear involves a portion of the meniscus where healing is poor, the surgeon might trim away ragged edges along the tear to allow the joint to move smoothly.
• Surgery to remove the entire meniscus (total meniscectomy) — This option is reserved for tears that cannot be treated in any other way. Doctors try to avoid this, because it leaves the knee without a meniscus and greatly increases the wear-and-tear on the ends of the femur and tibia. In the long run, this also increases the risk of arthritis in the knee.

If you need surgery to correct a torn meniscus, it usually can be done using arthroscopy (camera-guided surgery) as a same-day procedure. After the procedure, you will begin physical therapy to help strengthen your knee muscles, reduce pain and swelling, and return the knee’s full range of motion.

Call your doctor to schedule an evaluation whenever an injured knee:

• Locks, catches or can’t be fully extended
• Becomes very painful or swollen
• Makes a click, pop or grinding sound when you move it
• Buckles, gives way or feels generally weak

In most cases, the prognosis is very good. If your torn meniscus has been repaired surgically or partially removed, you probably will be able to resume your normal athletic activities once you’ve finished physical therapy.

According to long-term studies, most patients who have had a meniscus repaired feel very satisfied with the results of their surgery, even 10 or 11 years after the procedure. Unfortunately, some people with meniscus injuries eventually develop arthritis in the injured knee. The highest risk is among those who’ve had a part or all of the meniscus removed, since these surgeries take away some or all of the cushioning effect of the meniscus.

Diseases and Conditions Center

All ArmMed Media material is provided for information only and is neither advice nor a substitute for proper medical care. Consult a qualified healthcare professional who understands your particular history for individual concerns.