A torn meniscus is one of the most common knee injuries. Any activity that causes you to forcefully twist or rotate your knee, especially when putting the pressure of your full weight on it, can lead to a torn meniscus.
Each of your knees has two menisci — C-shaped pieces of cartilage that act like a cushion between your shinbone and your thighbone. A torn meniscus causes pain, swelling and stiffness. You also might have trouble extending your knee fully.
Conservative treatment — such as rest, ice and medication — is sometimes enough to relieve the pain of a torn meniscus and give the injury time to heal on its own. In other cases, however, a torn meniscus requires surgical repair.
If you've torn your meniscus, you may experience the following signs and symptoms in your knee:
A popping sensation
Swelling or stiffness
Pain, especially when twisting or rotating your knee
Difficulty straightening your knee fully
Experiencing what feels like a block to moving your knee, as if your knee were locked in place
When to see a doctor
Contact your doctor if your knee is painful or swollen, or if you can't move your knee in the usual ways.
A torn meniscus can result from any activity that causes you to forcefully twist or rotate your knee, such as aggressive pivoting or sudden stops and turns. Even kneeling, deep squatting or lifting something heavy can sometimes lead to a torn meniscus. In older adults, degenerative changes of the knee may contribute to a torn meniscus.
Anyone performing activities involving aggressive twisting and pivoting of the knee is at risk of a torn meniscus. The risk is particularly high for athletes — especially those who participate in contact sports, such as football, or activities that involve pivoting, such as tennis or basketball. The risk of a torn meniscus also increases as you get older, due to years of wear and tear on your knees.
A torn meniscus can lead to knee instability, inability to move your knee normally or persistent knee pain. You also may be more likely to develop osteoarthritis in the injured knee.
Often, a torn meniscus can be identified during a physical exam. Your doctor may manipulate your knee and leg bones into different positions to help pinpoint the cause of your signs and symptoms.
X-rays. Because a torn meniscus is made of cartilage, it won't show up on X-rays. But X-rays can help rule out other problems with the knee that may have similar symptoms.
Ultrasound. Ultrasound can allow the doctor to examine the inside of your knee in motion. This can help determine if you have a loose flap of cartilage getting caught between the moving parts in your knee.
Magnetic resonance imaging (MRI). MRI uses radio waves and a strong magnetic field to produce cross-sectional images of internal structures. It can create detailed images of both hard and soft tissues within your knee.
In some cases, your doctor may use an instrument known as an arthroscope to examine the inside of your knee. The arthroscope is inserted through a tiny incision near your knee. The device contains a light and a small camera, which transmits an enlarged image of the inside of your knee onto a monitor. If necessary, surgical instruments can be inserted through the arthroscope or through additional small incisions in your knee.
Treatment for a torn meniscus often begins conservatively. Your doctor may recommend:
Rest. Avoid activities that aggravate your knee pain, especially any activity that might cause you to twist your knee. You might want to use crutches to take pressure off your knee and promote healing.
Ice. Ice can reduce knee pain and swelling. Use a cold pack, a bag of frozen vegetables or a towel filled with ice cubes for about 15 minutes at a time. Do this every four to six hours the first day or two, and then as often as needed.
Medication. Over-the-counter pain relievers also can help ease knee pain.
Physical therapy can help you strengthen the muscles around your knee and in your legs to help stabilize and support the knee joint. Arch supports or other shoe inserts can help to distribute force more evenly around your knee or decrease stress on certain areas of your knee.
If your knee remains painful, stiff or locked, your doctor may recommend surgery. It's sometimes possible to repair a torn meniscus, especially in children and young adults. If the tear can't be repaired, the meniscus may be surgically trimmed. Surgery may be done through tiny incisions using an arthroscope. After surgery, you will need to do exercises to optimize knee strength and stability.