Even in severe or complex meniscal tears, the knee may look normal, apart from possible swelling. There often isn’t much to see since the injury is internal. Describe your symptoms to your doctor as soon as possible, and be thorough, even if your knee looks normal.
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What is a meniscus tear?
A torn meniscus or meniscal tear is one of the most common knee injuries, usually the result of traumatic injury or degenerative wear and tear.
The meniscus is a C-shaped piece of cartilage in the knee that acts as a shock absorber between the upper and lower leg (the femur and the fibula and tibia). When standing, the meniscus bears up to 30-55% of the load from your body weight. Each knee has two menisci, one on each side, like a pair of parentheses ( ). It's possible to tear either meniscus on either knee.
Meniscus tears are classified by the structure and direction of the tear, which can affect your treatment options and recovery. Common types of tears include:
- Radial tear: A tear running across the width of the meniscus
- Longitudinal tear: A tear running the length of the meniscus
- Flap tear: A partial tear that creates a loose "flap" that's still connected to the meniscus, like a hangnail
- Bucket handle tear: A complex tear that creates a handle-like opening in the meniscus body
- Degenerative tears: Variable, but often complex, tears composed of multiple tear types and/or fraying at the edge of the meniscus
In addition to the tear type, your sports medicine specialist or surgeon will identify the location of the tear:
- Horn tears: Located on one of the ends of the meniscus, horn tears are more common in the back portion (posterior horn tear) than the front portion (anterior horn tear)
- Central tears: Tears on the inner 2/3 of the meniscus are called central tears
- Peripheral tears: A tear located toward the outside edge of the meniscus
Meniscus tear symptoms
The most common signs of a torn meniscus in the knee are:
- Pain, especially on the back or sides of the knee
- Swelling and stiffness
- Weakness or instability
- Catching, clicking, or locking
- Reduced range of motion
- Inability to fully extend the leg
Many symptoms of a meniscus tear can take several days to surface following injury. However, if the tear is sudden or “acute,” you may hear or feel a popping in the knee when it occurs.
A torn meniscus usually causes pain, stiffness, and swelling in the knee. In some cases, the torn portions of the meniscus can move out of place and get caught in the knee joint. When this happens, you may feel like something is out of place, or like you're compressing something in the knee joint, when you try to extend your leg.
Most people can walk safely on a torn meniscus without causing problems. Because symptoms often don't appear for several days, you may have already walked on a torn meniscus without realizing it. However, depending on your pain threshold and the severity of the tear, walking may be uncomfortable. Some tears will cause the knee to "lock up," making it difficult or impossible to walk.
In some cases, walking with a torn meniscus may worsen the condition of the meniscus. Even if you can walk safely, you should be very careful about movements—such as twisting or squatting—that may cause the meniscus to tear further. Check with your doctor or sports medicine specialist about the kind of tear you have and what precautions you should follow while it heals.
What causes a torn meniscus?
Meniscal tears have two main causes: traumatic injury and degenerative wear and tear.
Traumatic meniscal tears usually occur during a sudden rotating movement while bearing weight, such as when twisting the upper leg while the foot stays in one place during sports and other activities. They're most common in athletes who play sports that involve these motions, like football, basketball, and soccer.
Degenerative meniscus tears occur because the meniscus weakens over time. If it becomes weak enough, daily activities like yard work can cause a meniscus tear. Degenerative tears are most common in people over 40.
Risk factors for a torn meniscus
Some people are at higher risk of a meniscal tear than others. Risk factors for a torn meniscus include:
- Sports: Athletes are at higher risk for a torn meniscus, especially in contact sports or activities that involve twisting and cutting motions.
- Gender: Men are 2.5x as likely to tear their meniscus than women.
- Body mass: A higher BMI is associated with a higher risk of meniscus tears.
- Other knee injuries: Patients with other knee injuries, like ACL tears, are more likely to have meniscus tears.
FAQs about meniscus tears
The recovery process and timeline depends on the nature of the tear. Meniscus tears vary considerably. If your tear is minor and in a part of the meniscus that receives blood flow, it may be possible to treat it without surgery. In many cases, though, due to limited blood flow to the area, the torn meniscus can't heal on its own, and will need surgery.
In general, meniscus tears don't directly cause pain outside of the knee. However, a meniscus tear makes your knee less stable, which can cause you to change the way you move. Compensating for knee pain and stability can cause pain elsewhere, such as in the hip or ankle.
Meniscus tears vary in terms of severity. Left untreated, it's possible for a torn meniscus to cause chronic pain, arthritis, and instability that can lead to other injuries.
On its own, running often won't make a meniscus tear worse. However, pivoting and fast changes of direction can put you at risk of further damaging the meniscus, so runners should be careful about how they move while running.
Often, you'll only notice symptoms if the torn portion of your meniscus is out of place, so it's common for symptoms of a meniscus tear to come and go until the issue is resolved. Unless the tear heals completely or you have the damaged portion removed with surgery, your symptoms will persist, even if, at times, they seem to go away.
That depends on the sport and the severity of the tear. Minor tears may not cause severe symptoms, and you may be tempted to continue playing. However, many popular sports—such as basketball, soccer, and tennis—involve the motions that put you at risk for a meniscus tear. Continuing to play may increase your chances of making the tear worse. Even if the tear doesn't worsen, continuing to play on a torn meniscus may make it harder for the tear to heal.
