What is a meniscus tear?
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. The menisci keep your knee steady by balancing your weight across the knee. A torn meniscus can prevent your knee from working right.
What causes a meniscus tear?
A meniscus tear is usually caused by twisting or turning quickly, often with the foot planted while the 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.
What are the symptoms?
There are three types of meniscus tears. Each has its own set of symptoms.
With a minor tear, you may have slight pain and swelling. This usually goes away in 2 or 3 weeks.
A moderate tear can cause pain at the side or center of your knee. Swelling slowly gets worse over 2 or 3 days. This may make your knee feel stiff and limit how you can bend your knee, but walking is usually possible. You might feel a sharp pain when you twist your knee or squat. These symptoms may go away in 1 or 2 weeks but can come back if you twist or overuse your knee. The pain may come and go for years if the tear isn't treated.
In severe tears, pieces of the torn meniscus can move into the joint space. This can make your knee catch, pop, or lock. You may not be able to straighten it. Your knee may feel "wobbly" or give way without warning. It may swell and become stiff right after the injury or within 2 or 3 days.
If you are older and your meniscus is worn, you may not know what you did to cause the tear. You may only remember feeling pain after you got up from a squatting position, for example. Pain and slight swelling are often the only symptoms.
How is a meniscus tear diagnosed?
Your doctor will ask about past injuries and what you were doing when your knee started to hurt. A physical exam will help your doctor find out if a torn meniscus is the cause of your pain. Your doctor will look at both knees and check for tenderness, range of motion, and how stable your knee is. X-rays are also usually done.
How is it treated?
How your doctor treats your meniscus tear depends on several things, such as the type of tear, where it is, and how serious it is. Your age and how active you are may also affect your treatment choices.
Treatment may include:
- Rest, ice, wrapping the knee with an elastic bandage, and propping up the leg on pillows.
- Physical therapy.
- Surgery to repair the meniscus.
- Surgery to remove part of the meniscus.
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Symptoms of a meniscus tear depend on the size and location of the tear and whether other knee injuries occurred along with it. Pain can also be due to swelling and injury to surrounding tissues.
With small tears, you may have minimal pain at the time of the injury. Slight swelling often develops gradually over several days. Many times you can walk with only minimal pain, although pain increases with squatting, lifting, or rising from a seated position. These symptoms usually go away in 2 to 3 weeks although pain may recur with bending or twisting.
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 gradually over 2 to 3 days and may make the knee feel stiff and limit bending. There is often sharp pain when twisting or squatting. Symptoms may diminish in 1 to 2 weeks but recur with activities that involve twisting or from overuse. The pain may come and go over a period of years if left untreated.
Larger tears usually cause more pain and immediate swelling and stiffness. Swelling can develop over 2 to 3 days. 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. The knee can also feel "wobbly" or unstable, or give way without warning. If other injuries occurred with the meniscus tear, especially torn ligaments, you may have increased pain, swelling, a feeling that the knee is unstable, and difficulty walking.
Older people whose menisci are worn may not be able to identify 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 minimal 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.
Exams and Tests
During an examination 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 evaluate tenderness, range of motion, and knee stability. An X-ray is usually done to evaluate the knee bones if there is swelling, if there is pain at a certain place (point tenderness), or if you cannot put weight on your leg.
Your knee may be too painful or swollen for a full exam. In this case, your doctor may withdraw 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 with rest, ice, compression, and elevation.
Your family doctor or an emergency room doctor may refer you to an orthopedist for a more complete examination. An orthopedist may order a magnetic resonance imaging (MRI) if the diagnosis is uncertain. An MRI typically gives a good picture of the location and extent of a meniscus tear and also provides images of the ligaments, cartilage, and tendons.
An orthopedist may recommend arthroscopy, a procedure used to examine and repair the inside of the knee joint by inserting a thin tube (arthroscope) containing a camera with light through a small incision near the knee joint. With arthroscopy, the orthopedist can directly view and possibly treat the meniscus and other parts of the knee.
There are many things to consider when deciding how to treat your torn meniscus, including the extent and location of the tear, your pain level, your age and activity level, your doctor's preference, and when the injury occurred. Your treatment choices are:
- Nonsurgical treatment with rest, ice, compression, elevation, and physical therapy. This may include wearing a temporary knee brace.
- Surgical repair to sew the tear together.
- Partial meniscectomy, which is surgery to remove the torn section.
- Total meniscectomy, which is surgery to remove the entire meniscus. This is generally avoided, because this option increases the risk for osteoarthritis in the knee.
Whenever possible, meniscus surgery is done using arthroscopy, rather than through a large cut in the knee.
The location (zone) of the tear is one of the most important things that helps determine treatment.
- Tears at the outer edge of the meniscus (red zone) tend to heal well because there is good blood supply. Minor tears may heal on their own with a brace and a period of rest. If they do not heal or if repair is deemed necessary, the tear can be sewn together. This repair is usually successful in the red zone.
- The inner two-thirds (white zone) of the meniscus does not have a good blood supply, so it does not heal well either on its own or after repair. If torn pieces float into the joint space, which may result in a "locked" knee or cause other symptoms, the torn portion is removed (partial meniscectomy) and the edges of the remaining meniscus are shaved to make the meniscus smooth.
- When the tear extends from the red zone into the white zone, there may be enough blood supply for healing. The tear may be repaired or removed. This is something the orthopedic surgeon decides during the surgery.
Also, the pattern of the tear may determine whether a tear can be repaired. Longitudinal tears are often repairable. Radial tears may be repairable depending on where they are located. Horizontal and flap (oblique) tears are generally not repairable.
It is preferable to preserve as much of the meniscus as possible. If the meniscus can be repaired successfully, saving the injured meniscus by doing a meniscal repair reduces the occurrence of knee joint degeneration compared with partial or total removal (meniscectomy). Meniscus repair is more successful in younger people (experts think people younger than about 40 years old do best), in knees that have good stability from the ligaments, if the tear is in the red zone, and if the repair is done within the first few weeks after the injury (acute).footnote 1
Meniscal repair may prevent degenerative changes in the knee joint. Many doctors believe that a successful meniscus repair lowers the risk of early-onset arthritis, because it reduces the stress put on the knee joint.
Orthopedists most often perform meniscus surgery with arthroscopy, a procedure used both to examine and then to treat the inside of a joint by inserting a thin tube (arthroscope) containing a camera and a light through small incisions near the joint. Surgical instruments are inserted through other small incisions near the joint. Some tears require open knee surgery.
Rehabilitation (rehab) varies depending on the injury, the type of surgery, your orthopedic surgeon's preference, and your age, health status, and activities. Time periods vary, but in general meniscus surgery is usually followed by a period of rest, walking, and selected exercises. After you have full range of motion without pain and your knee strength is back to normal, you can return to your previous activity level.
For some exercises you can do at home (with your doctor's approval), see:
Other knee injuries, most commonly to the anterior cruciate ligament (ACL) and/or the medial collateral ligament, may occur at the same time as a meniscus tear. In these cases, the treatment plan is different. Typically, your orthopedist will treat your torn meniscus, if needed, at the same time that ACL surgery is done. In this case, the ACL rehab plan is followed.
Meniscal transplant is an experimental treatment for meniscal tears. It might be a good option for a meniscus that is already weakened or scarred due to previous injury or treatment. In this surgical procedure, a piece of meniscus cartilage from a donor (allograft) is transplanted into the knee.
To be eligible for meniscal transplantation, a person:
- Should be younger than age 50.
- Must be finished growing.
- Must not be obese.
- Has knee pain and swelling that has not responded to other treatment.
- Must have no arthritis (or minimal arthritis) in the knee joint.
- Must have a well-aligned knee, meaning the legs are not bent outward at the knees (bowlegged) or bent inward at the knees (knock-kneed).
If you have recently injured your knee, follow these first-aid steps to reduce pain and swelling:
- Rest and reduce activity. Avoid motions or positions that cause discomfort. Depending on your injury and pain, your doctor may recommend crutches and a brace.
- 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.
- Elevate your leg higher than your heart.
- Ask your doctor if you can take nonsteroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen or naproxen to relieve pain and reduce swelling. Be safe with medicines. Read and follow all instructions on the label.
- Follow your doctor's instructions for rest and rehabilitation of your knee.
If the tear is minor and your symptoms go away, your doctor may recommend a set of exercises to build up your quadriceps and hamstring muscles and increase your flexibility. It's important to follow your doctor's guidance to avoid a new or repeat injury.
Your recovery time after surgery will depend on many things, including the injury and the type of surgery you have.
- McMahon PJ, et al. (2014). Sports medicine. In HB Skinner, PJ McMahon, eds., Current Diagnosis and Treatment in Orthopedics, 5th ed., pp. 88–155. New York: McGraw-Hill.
Other Works Consulted
- American College of Radiology (2011). ACR Appropriateness Criteria: Acute Trauma to the Knee. Available online: http://www.acr.org/SecondaryMainMenuCategories/quality_safety/app_criteria/pdf/ExpertPanelonMusculoskeletalImaging/AcuteTraumatotheKNEEDoc2.aspx.
- Paxton ES, et al. (2011). Meniscal repair versus partial meniscectomy: A systematic review comparing reoperation rates and clinical outcomes. Arthroscopy, 27(9): 1275–1288.
Current as ofSeptember 20, 2018
Author: Healthwise Staff
Medical Review: William H. Blahd, Jr., MD, FACEP - Emergency Medicine
Adam Husney, MD - Family Medicine
E. Gregory Thompson, MD - Internal Medicine
Kathleen Romito, MD - Family Medicine
Patrick J. McMahon, MD - Orthopedic Surgery, Sports Medicine
Current as of: September 20, 2018