What is a torn meniscus?
The torn meniscus is a piece of cartilage that provides a cushion between the femur (thigh bone) and the tibia (shin bone). There are two menisci in each knee joint.
A torn meniscus can be damaged or broken during activities that put pressure on or rotate the knee joint. Making a hard tackle on the soccer field or a sudden turn on the basketball court can result in a meniscus tear.
However, you don’t have to be an athlete to suffer a meniscus tear. Simply getting up too quickly from a squat can also cause a meniscus tear. According to Boston Children’s Hospital, more than 500,000 meniscus tears occur each year in the United States.
Liable on the severity of your injury, treatment options can vary from home remedies to outpatient surgery. You can help prevent this injury by doing exercises that strengthen your leg muscles and using proper techniques during contact activities or sports.
The 6 types of meniscus tears
- Intrasubstantial / Incomplete tear: An intrasubstance tear is a common finding on an MRI report. Seen in the upper left corner of the image, an intrasubstance tear generally appears normal at the time of surgery. These are often a sign of early degenerative changes in the meniscus tissue, but they are rarely the sign of a problem. Imperfect and transubstantial tears of the meniscus are stable injuries and usually do not require any surgical treatment. When people are in their 20s and 30s, intrasubstance changes in the meniscus tissue are most often seen on MRI.
- Radial tear: Radial meniscus tears, shown in the middle of the upper row in the image, are the most common type of meniscus tear. These tears are found within the avascular zone of the meniscus, where there is no blood supply. and therefore there is little healing ability of these tears. So, when these tears require surgical treatment, usually the only option is to trim the injured part of the meniscus.
- Horizontal tear: A horizontal tear is a tear that is usually amenable to meniscus overhaul. Observed in the higher right corner of the image, a horizontal tear runs through the circumferential fibres of the meniscus. Instead of removing the damaged part of the meniscus, a horizontal tear can be sewn. The key to determining the treatment of these tears is their location. If it is within the vascular portion of the meniscus (near the outer edge), then there is potential for healing and therefore repair. When more centrally located, these tears will not heal, even if repaired.
- Flap tear: A flap tear of the meniscus, shown in the lower right corner of the image, is an unusual pattern of the tear. In circumstances where the flap is causing symptoms of knee stiffness, usually, the meniscus flap can simply be removed without removing much tissue at all.
- Complex tear: A complex tear means that there is a combination of tear patterns. In the middle image in the bottom row, a complex tear often involves both radial and horizontal tear patterns. Complex tears are not normally treated with meniscus repair due to the complex nature of the tear. In some unusual circumstances, part of the torn meniscus can be removed, while other parts can be repaired.
- Bucket handle tear: A bucket handle tear is a big type of horizontal meniscus tear.10 These tears often cause the knee to muddle by causing the torn part of the meniscus to block the normal movement of the knee. Bucket handle tears often require more vital surgical treatment to allow the knee to begin to bend again.
Causes of a torn meniscus
A forceful twist or sudden stop can cause the end of the femur to move toward the top of the tibia, pinching and potentially tearing the cartilage of the meniscus. This knee injury can also occur when squatting or kneeling deeply, especially when lifting a heavyweight. Meniscus tear injuries often occur during sports activities, especially contact sports such as soccer and hockey. Movements that require pivoting and stopping suddenly, in sports such as tennis, basketball, and golf, can also cause meniscus damage. Sports injury does not have to occur during a game, but it can also occur in practice, where the same movements lead to meniscus damage.
The risk of developing a torn meniscus increases with age because cartilage gradually begins to wear away, losing its blood supply and strength. Collective body weight also puts more pressure on the meniscus. Routine daily doings, such as walking and ascending stairs, increase the potential for wear and tear, degeneration, and tears. It is estimated that six out of 10 patients over the age of 65 have a degenerative meniscus tear. Many of these tears may never cause problems.
Because approximately of the cartilage fibres are unified with those of the ligaments that surround the knee, meniscal injuries can be associated with tears of the collateral and cruciate ligaments, depending on the mechanism of injury. While normal cartilage is shaped like a “C” or crescent, there is a variant shape that is oval or discoid. This meniscus is thicker and more prone to injury and tears.
Symptoms of a torn meniscus
When a meniscus tear occurs, you may hear a clicking sound around the knee joint. Later, you can experience:
- Pain, especially when the area is touched
- Difficulty moving the knee or inability to move it through a full range of motion
- The feeling that your knee is locking or trapping
- The feeling that your knee is giving out or you can’t hold it
You may also experience a slipping or popping sensation, which is usually an indication that a piece of cartilage has come loose and is blocking the knee joint.
Contact your doctor if you experience any of these symptoms and they persist for more than a few days or occur after your knee is injured. Call your doctor right away if your knee locks up and you can’t bend it after straightening it.
Torn meniscus treatment
Treatment of meniscal tears depends on the size and location of the tear. Other issues that influence treatment include age, activity level, and related injuries. The outer part of the meniscus, often called the “red zone,” has a good blood supply and can sometimes heal on its own if the tear is small. In contrast, the inner two-thirds of the meniscus, known as the “white zone,” do not have a good blood supply. Tears in this region will not heal on their own, as this area lacks blood vessels to bring healing nutrients.
Fortunately, not all meniscal tears require surgery. If your knee does not lock, is stable, and symptoms resolve, non-surgical treatment may be sufficient. To speed up recovery, you can:
- Rest your knee. Limit activities to include walking if your knee hurts. Use crutches to help relieve pain.
- Apply ice to the knee to reduce pain and swelling. Do it for 15-20 minutes every 3-4 hours for 2-3 days or until the pain and swelling go away.
- Compress your knee. Wear an elastic bandage or neoprene-type sleeve on your knee to control swelling.
- Elevate your knee with a pillow under your heel when sitting or lying down.
- Take anti-inflammatory medications. Nonsteroidal anti-inflammatory drugs (NSAIDs), such as Advil, Aleve, or Motrin, will help with pain and swelling. However, these medications can have side effects, such as an increased risk of bleeding and ulcers. They should only be used occasionally unless your doctor specifically indicates otherwise.
- Use stretching and strengthening exercises to help reduce stress on your knee. Ask your doctor to commend a physical therapist for leadership.
- Avoid impact activities like running and jumping.
However, these conservative treatments are not always enough. If a tear is large, unstable, or causes blocking symptoms, surgery may be required to repair or remove the unstable edges. The procedure is usually fairly straightforward, and you can often go home the same day. You may need a brace later to protect yourself if a repair is done.
For 85% to 90% of people who have surgery for a meniscus tear, the temporary results are good to outstanding. But in the long term, people who have a large meniscal injury that cannot be repaired may be at higher risk of developing knee arthritis.
Diagnosis of a torn meniscus
The diagnosis of a knee injury starts with history and physical examination. If there is an acute injury, the doctor will ask about the mechanism of that injury to help understand the stresses that were applied to the knee. With chronic knee discomfort, the initial injury may not be remembered, but many patients participating in sporting events or training can identify the specific time and details of the injury. Non-athletes may recall a deep turn or curve at work or doing housework.
There is a true art to physical examination of the knee. By reviewing (looking), palpating (feeling), and applying specific diagnostic manoeuvres, the physician, trainer, or bodily therapist can often make the diagnosis of a torn meniscus.
The physical examination often includes palpating the joint for warmth and tender areas, assessing the stability of the ligaments, and testing the range of motion of the knee joint and the power of the quadriceps and hamstrings. Many tests have been described to evaluate the internal structures of the knee. The McMurray test, named after a British orthopaedic surgeon, has been used for over 100 years to make the clinical diagnosis of a torn meniscus. The healthcare professional flexes the knee and rotates the tibia while feeling the joint. The test is positive for a possible tear if a click is felt.
Magnetic timbre imaging (MRI) is the test of choice to settle the diagnosis of a torn meniscus. It is a non-invasive test that can visualize the internal structures of the knee, including cartilage and ligaments, the surface of the bones, and the muscles and tendons that surround the knee joint. An added benefit of MRI before surgery is that by knowing the anatomy, the orthopaedic surgeon can plan a possible knee surgery and discuss alternative treatments with the patient before the operation begins.
Plain X-rays cannot be used to identify meniscal tears, but they can be obliging in looking for bone changes, containing fractures, arthritis, and loose bone fragments within the joint. In older patients, X-rays of both knees can be taken while the patient is standing. This lets the joint spaces to be likened to assess the degree of cartilage wear. Cartilage takes up space within the joint, and if the joint space narrows, it may be an indicator that there is less cartilage present, probably due to degenerative disease. Plain X-rays can also uncover other causes of knee pain, such as arthritis and pseudogout.
Before the widespread use of MRI, knee arthroscopy was used to confirm the diagnosis of a torn meniscus. In arthroscopy, the orthopaedic surgeon supplements a small scope into the knee and looks directly at the structures inside the joint. The added benefit of arthroscopy is that the injury can be repaired at the same time using additional tools that are inserted into the joint. The downside to arthroscopy is that it is a surgical procedure with all the potential risks associated with surgery.
Risk factors for a torn meniscus
Performing activities that involve an aggressive twisting and turning of the knee puts you at risk for a meniscus tear. The risk is particularly high for athletes, especially those who participate in contact sports, such as soccer, or activities that involve pivoting, such as tennis or basketball. Wear and tear on your knees as you age increases the risk of a meniscus tear. So does obesity.
Complications of a torn meniscus
A torn meniscus can lead to a feeling of giving the knee, an inability to move it normally, or persistent pain in the knee. You may be more likely to develop osteoarthritis in your injured knee.
Prevention of torn meniscus
Meniscus tears are difficult to prevent as they are usually the result of an accident. But some precautions can reduce the risks of a knee injury. You should:
- Keep your thigh muscles strong with regular exercises.
- Warm-up with light activities before exercise.
- Give your body time to rest between workouts.
- Make sure your shoes have enough support and fit properly.
- Stay flexible.
- Never increase the intensity of your training sharply.