A meniscus tear is a common knee injury. The meniscus is a rubbery, C-shaped disc that cushions your knee. Each knee has two menisci (plural of meniscus)—one at the outer edge of the knee and one at the inner edge. They keep your knee steady by balancing your weight across the knee. A torn meniscus can prevent your knee from working right.
Where a meniscus tear occurs is one of the most important things that affects healing. Tears at the outer edge (red zone) tend to heal well because there is a good blood supply. The inner area (white zone) lacks a good blood supply and therefore does not heal well.
The type of tear often determines whether a tear can be repaired. Longitudinal tears are often repairable. Radial tears may be repairable depending on where they are located. Oblique (flap) tears and another type called horizontal tears are generally not repairable.
What are the symptoms of a meniscus tear?
Symptoms of a meniscus tear, such as pain, depend on the size and location of the tear and whether other knee injuries occurred along with it. Pain can also be caused by swelling and injury to surrounding tissues.
With small tears, you may have little to no pain at the time of the injury. A little swelling often develops slowly over a couple of days. Many times, people can walk with only a little pain, although pain increases when you squat, lift, or rise from a seated position. These symptoms usually go away, although you may still have pain when you bend or twist your knee.
In a typical moderate tear, you feel pain at the side or in the center of the knee, depending on where the tear is. Often, you are still able to walk. Swelling usually increases slowly over a few days and may make the knee feel stiff and limit bending. There is often sharp pain when you twist or squat. Symptoms may go away but can come back from overuse or when you do activities that involve twisting. The pain may come and go over a period of years if the tear isn't treated.
Larger tears usually cause more pain and immediate swelling and stiffness. Pieces of the torn meniscus can float into the joint space. This can make the knee catch, pop, or lock. You may not be able to straighten your knee. If other injuries occurred with the meniscus tear, especially torn ligaments, you may have increased pain and swelling, a feeling that the knee is unstable, and trouble walking.
Older people whose menisci are worn may not be able to recall a specific event that caused a tear, or they may recall symptoms developing after a minor incident such as rising from a squatting position. Pain and a little swelling are often the only symptoms.
Pain at the inside of the knee can mean there is a tear to the medial meniscus. Pain at the outer side of the affected knee can mean there is a tear to the lateral meniscus.
What causes a meniscus tear?
A meniscus tear is usually caused by twisting or turning quickly, often with your foot planted while your knee is bent. Meniscus tears can occur when you lift something heavy or play sports. As you get older, your meniscus gets worn. This can make it tear more easily.
How is a meniscus tear diagnosed?
When checking for a possible meniscus tear, your doctor will ask you about past injuries and what you were doing when your knee started to hurt. He or she will do an exam of both knees to check for tenderness and range of motion and see how stable your knee is. An X-ray is usually done to check the knee bones if you have swelling, if you have pain at a certain place (point tenderness), or if you can't put weight on your leg.
Your knee may be too painful or swollen for a full exam. In this case, your doctor may remove fluid from your joint and inject a numbing medicine (local anesthetic) into the joint. This might relieve your pain enough that you can have an exam. Or the exam may be postponed for a week while you care for your knee at home using rest, ice, compression, and elevation.
Your doctor may order an MRI if the diagnosis is not clear. An MRI typically gives a good picture of where the tear is and how severe it is. It also shows the ligaments, cartilage, and tendons.
Your family doctor or an emergency room doctor may refer you to an orthopedist for a more complete exam. The orthopedist may recommend arthroscopy. It is a procedure used to look at and repair the inside of the knee joint. The doctor inserts a thin tube called an arthroscope through a small cut near the knee joint. The arthroscope has a camera with a light. With the scope, the doctor can see the meniscus and other parts of the knee.
Courtesy of Intermountain Medical Imaging, Boise, Idaho. All rights reserved.
Figure 1 is a side view of the knee that shows the normal location of the outside, or lateral, meniscus. Figure 2 is a similar view that shows a piece of meniscus that has been torn and moved.
How is a meniscus tear treated?
Your choices for treating a torn meniscus are:
- Treatment without surgery. This includes resting, using ice, wrapping the knee in an elastic bandage, propping it up on pillows, and doing physical therapy. This treatment choice may include wearing a temporary knee brace.
- Surgery to sew the tear together.
- Surgery to remove the torn section of the meniscus.
- Surgery to remove the entire meniscus.
There are many things to think about when deciding how to treat a torn meniscus. These things include where the tear is and how serious it is, your pain level, your age and activity level, your doctor's preference, and when the injury happened. The decision about whether to have surgery depends on the kinds of symptoms you have and how bad they are, not just on how big the tear is. You may have a large tear but still decide not to have it repaired.
Meniscus repair is more successful if:
- You are younger. Experts think people younger than about age 40 do best.
- Your knee has good stability from the ligaments.
- The tear is in the outer edge of the meniscus.
- The repair is done soon after the injury.
How can you care for yourself when you have a meniscus tear?
- Rest your knee when possible.
- Do not squat or kneel.
- Take pain medicines exactly as directed.
- If the doctor gave you a prescription medicine for pain, take it as prescribed.
- If you are not taking a prescription pain medicine, ask your doctor if you can take an over-the-counter medicine.
- Put ice or a cold pack on your knee for 10 to 20 minutes at a time. Try to do this every 1 to 2 hours for the next 3 days (when you are awake) or until the swelling goes down. Put a thin cloth between the ice and your skin.
- Prop up the sore leg on a pillow when you ice your knee or any time you sit or lie down during the next 3 days. Try to keep your leg above the level of your heart. This will help reduce swelling.
- Follow your doctor's directions for using crutches or a knee brace, if suggested.
- Follow your doctor's directions for exercises to keep your knee mobile and your leg muscles strong. Here are a few exercises you can try if your doctor says it is okay.
- Quad sets: Lie down on the floor or the bed with your injured leg straight. Fully extend your leg—there should be no or little bend in your knee. Tighten the thigh (quadriceps) of your injured leg for 6 seconds. Do not lift your heel up. Relax your quadriceps for 10 seconds. Repeat this exercise 8 to 12 times several times during the day.
- Straight-leg raises to the front: Lie down on the floor or the bed with your injured leg flat and your uninjured leg bent so that the bottom of your foot is on the floor or bed. Tighten the quadriceps of your injured leg. Keeping your knee as straight as possible, lift your injured leg off the bed until your heel is about 12 inches above the bed or floor. Hold for 6 seconds and then lower slowly. Do 8 to 12 repetitions.
- Straight-leg raises to the back: Lie on your stomach, and lift your leg straight up behind you (toward the ceiling). Lift your toes about 6 inches off the floor, hold for about 6 seconds, and then lower slowly. Do 8 to 12 repetitions.
- Heel raises: Stand with your feet a few inches apart. Rest your hands lightly on a counter or chair in front of you. Slowly raise your heels off the floor while keeping your knees straight. Hold for 6 seconds, and then slowly lower your heels to the floor. Do 8 to 12 repetitions several times during the day.
Copyrighted material adapted with permission from Healthwise, Incorporated. This information does not replace the advice of a doctor.