Symptoms
The symptoms of a meniscus tear can be different based on how serious the injury is. If you have a minor tear, you might only notice a bit of pain and swelling that goes away after two or three weeks.
If your knee tear is more serious, you might notice: 
- A popping feeling or sound in the knee where the meniscus is torn. 
- Pain in the center of the knee or on one of the sides, especially when you twist your knee or squat down. This pain can go away after a couple of weeks, but you might notice that it comes back if you don’t get treatment. 
- Still or swollen knees, especially in the first 2 or 3 days after you have the tear. 
- Inability to move your knee as far forward, back, or side-to-side as you could before you were hurt. 
- Locking or popping feeling when you bend it. 
- Inability to straighten your knee all the way. 
- A feeling of weakness or lack of support in the knee. 
Causes
A meniscus tear is caused by putting a sudden, twisting force on the knee. They happen most often to athletes. 
Common reasons why people have knee tears include: 
- Twisting or over-flexing the knee. 
- Quickly stopping and changing direction while you run. 
- Landing from a jump. 
- Turning too fast while walking or playing sports. 
- Kneeling down on the floor. 
- Squatting far down and lifting heavy objects. 
- Getting hit on your knee. 
As you get older, your meniscus becomes weaker and easier to tear. Activities that might not have injured your knee when you were younger can cause a meniscus tear when you are older. 
Diagnosis & Tests, Treatment, & Prevention
Diagnosis & Tests
To diagnose a meniscus tear, your doctor will ask about your injury and your overall health and examine your knee. 
Imaging tests may be recommended to confirm or rule out a meniscus tear: 
- X-ray uses radio waves to create pictures of your knee. It may reveal a problem with a bone or another medical condition. 
- MRI (magnetic resonance imaging) uses magnets and radio waves to create a more detailed image of the tissues in your knee. It can show if the meniscus is torn or if a problem with a ligament or a tendon is the cause of your problem. 
- Ultrasound uses sound waves to create images of the joint. It can show swelling or damage in the affected area. 
Arthroscopic knee surgery may be recommended to diagnose and repair problems with your knee. During surgery, the surgeon inserts an arthroscope (a tiny camera) into your knee, and projects a large picture of your knee on a screen, giving a close look at the problems. The surgeon can then make small incisions (cuts) and insert tools to repair or remove damaged tissue.  With arthroscopic surgery, your incisions are small and your recovery is relatively fast. Most patients can go home the day of surgery.  Most of the time, arthroscopic surgery is only considered after you have tried all other options, like medicine, knee braces, changes in activity, and/or physical therapy.  
Treatments
Initial treatments for a meniscus injury may include: 
- Rest.  You should stay off your feet until your meniscus tear is healed. Don’t walk, run, or play sports because this can make your injury worse. 
- Ice.  You should put ice on your knee as soon as possible. Leave it in place for 15 to 20 minutes 3 to 4 times a day, especially for the first two days after you are injured. This can decrease inflammation and pain. 
- Elevation. Put your foot on a couple of pillows to keep it above your heart and chest. This can help decrease swelling. 
- Non-steroidal anti-inflammatory (NSAID) medicines, such as ibuprofen, aspirin, or naproxen can also help reduce pain, swelling, and inflammation. 
Sometimes, Initial treatments are enough. However, if the problems persist, talk to your doctor The tear may be more serious and need additional treatments or tests. Depending on your injury, your doctor might recommend: 
- Knee arthroscopy. The surgeon inserts an arthroscope (a tiny camera) into your knee, and projects a large picture of your knee on a screen, giving a close look at the problems. The surgeon can then make small incisions (cuts) and insert tools to repair or remove damaged tissue. 
- Meniscus transplant. If your meniscus tear is very serious, and almost all of the cartilage is torn, you might need a surgery to transplant a new meniscus into your knee. 
After your meniscus tear is healed, you might need physical therapy to help restore your knee’s range of motion and rebuild its strength. 
Prevention
Meniscus tears usually happen during physical activity, especially contact sports like football, hockey, soccer, or rugby. They can also happen by landing from a jump or fall. Meniscus tears happen without warning and can be hard to prevent, but there are some steps you can take to reduce your risk of injury: 
- Exercise regularly. Strength training for your leg muscles can help stabilize and protect your knee, reducing the chance of meniscus tears and other injuries. 
- Warm up and stretch. You should prepare for sports or any other kind of exercise that involves the legs by stretching and warming up before you start. 
- Rest. You should take time to rest between sports and exercise activities. 
- Use the right shoes. Make sure you are using the right shoes for your sports, and replace athletic shoes regularly. Making sure that your shoes are laced up tight can keep your foot, leg, and knee more stable. 
- Knee brace. A knee brace can give extra support to your knee, and you might need it, especially if you have had another knee injury in the past.