A meniscal tear is a tear in the meniscus, a shock-absorbing structure in the knee. There are two menisci (plural of meniscus) in each knee, one on the inside (medial), and one on the outside (lateral).

Most injuries to the meniscus are caused by trauma, usually compression and twisting of the knee. Movements that can cause trauma to the knee include pivoting, cutting, and decelerating. Because aging tends to break down the inner tissues of the meniscus, minor trauma (such as squatting) can injure the meniscus in an older person.

A risk factor is something that increases your chance of getting a disease or condition. Risk factors for a meniscal tear include:

• Participating in contact sports
• Improper techniques for jumping, landing, pivoting, and cutting
• Previous ACL injury

Torn meniscus may or may not cause symptoms. The ones that do not cause symptoms are usually small tears located in the back of the knee.

Symptoms may include:

• "Popping" sound at the time of the injury
• Pain
• Tightness
• Swelling within the knee, often called "water on the knee"
• Locking up, catching, or giving way of the knee
• Tenderness in the joint

The doctor will ask about your symptoms and how you injured your knee, and perform a physical exam . The doctor will perform physical tests to decide if there is a tear. Tests may include:

• X-ray —a test that uses radiation to take a picture of structures inside the body. It will not show a meniscus tear, but may show some bone abnormality.
• MRI scan —a test that uses magnetic radiation waves to make pictures of the inside of the knee. This is effective in diagnosing a meniscal tear.
• Arthroscopy —a thin, lighted tube inserted through a small incision in the knee to look at the structures inside the knee. With the arthroscope, the tear will be seen and may be removed or repaired as deemed necessary.

If your knee locks up and is painful, your physician may determine that surgery is necessary to remove the damaged meniscus. For knees that are stable and aren't locking, the RICE treatment may be all that is needed, at least for a period of time.

• Rest—Take a break from activities that stress the knee joint. With rest, the knee will be less painful. Some meniscal tears that occur on the outside of the meniscus will heal with time.
• Ice—Apply ice in 15-minute periods during the first 24 hours after the injury and for several days after, if needed. This helps reduce swelling, inflammation, and pain.
• Compression—Wrap the knee in an elastic bandage . This will help stop swelling and provide support and protection for the knee. Do not pull the elastic tightly.
• Elevation—Keep the injured knee raised for the first 24 hours, including during sleep. This will help drain fluid and reduce swelling.