A meniscus is a C-shaped cartilage structure that provides shock absorption and cushioning in the knee joint. There are two menisci. They are located in between the thigh bone (femur) and the shin bone (tibia) in the knee. One is on the inside part of the knee called the "medial meniscus" and one is on the outside of the knee called the "lateral meniscus."
When a patient has a torn meniscus, he or she usually complains about sharp pain in the knee. Occasionally, a torn meniscus can become locked in between the shin bone and the thigh bone and cause the knee to be stuck. Other times, a torn meniscus becomes a mobile fragment that catches between the bones and causes pain.
Top view of a meniscus
Arthroscopic view of normal meniscus
A torn meniscus is similar to a hangnail. The same way that a hangnail can catch and cause discomfort, a torn meniscus can catch and get pinched between the bones in the knee during regular activities causing pain. Torn menisci can occur as a result of a singular traumatic event, such as an abrupt twist of the knee, or as the result of many years of wear and tear.
To diagnose a meniscus tear, a doctor will take a history and perform a physical examination. X-rays and MRI are ordered. X-rays show the bones of the knee but do not show the meniscus. The MRI shows the meniscus and any tears.
Top view of a torn meniscus
Arthroscopic view of a torn meniscus
The majority of meniscus tears do not heal on their own. Therefore, surgery is often recommended. Surgery for a torn meniscus is performed arthroscopically. Arthroscopic surgery uses small incisions and small tools, about the size of a pencil, to perform the procedure. All the work is visualized with a small camera, the arthroscope. The surgeon sees inside the knee with the arthroscope and its images are projected on a video screen.
Arthroscopic camera and tools in the knee
The torn meniscus fragment is removed and the remaining meniscus is trimmed. Occasionally, the meniscus is torn in such a way that it can be sewn back in place and will heal if stitches are placed across the tear. However, the majority of meniscus tears are treated by removing the torn fragment.
Even though a portion of the meniscus is removed in these procedures, a significant portion of a normal intact meniscus is left behind. While it does not function in the way that it did prior to the injury, a significant amount of its function is still retained.
A shaver removes the torn portion of the meniscus
View after torn portion of meniscus removed
Arthroscopic knee surgery for meniscus tears is done on an outpatient basis. No overnight stay is required in the hospital.
According to the Anesthesia Manual of Surgical Procedures, pain from meniscus surgery is rated at 3 out of 10 on a scale of 1 to 10, with 1 being no pain and 10 being the worst pain. Pain medication is given to control pain and keep patients comfortable after surgery. Pain predictably improves after surgery, especially after the first week.
The recovery after meniscus surgery depends upon whether a repair or a partial meniscus removal was performed. If a partial meniscus removal is performed, then a patient can usually resume his or her normal activities whenever incisions are healed, usually about two weeks after surgery. At that time, patients are usually ready to go back to an active lifestyle. Usually, no crutches necessary nor is there is a need for a brace.
If a repair is performed, weight-bearing restrictions may apply and crutches may be needed. Additionally, the patient may be restricted from returning to sports until appropriate healing has taken place. This can take up to six weeks or longer. Rehabilitation with physical therapy is often necessary, and if so, will be prescribed by the surgeon.