A meniscus is a C-shaped structure that is made out of a strong rubbery material termed fibrocartilage. Each knee has two menisci. These menisci reside between the femur (thigh bone) and the tibia (main bone in lower leg).

The main functions of a meniscus include shock absorption and load transmission. The secondary functions of a meniscus include joint stability, lubrication and nutrition.

In middle-aged and elderly people, meniscus tears are usually related to the normal age-related weakening and degeneration that the menisci undergo. Hence, a minor twist or fall can cause meniscus tears in these age populations.

In younger age populations, a more forceful injury event is usually required to cause a meniscus tear. A common mechanism of injury is a forceful twisting or rotation of the knee while the person’s full weight is born through that leg. Other mechanisms of injury can be jumps, jump landings and direct blows to the knee. All of these mechanisms of injury are seen in numerous sports.

When a meniscus tear initially occurs, a person may hear or feel a “pop” in the knee. The knee often hurts immediately and it may develop swelling. This pain and swelling can characteristically come and go.

Common symptoms reported by people with meniscus tears include:

• Pain
• Stiffness
• Swelling
• Knee “catching” or “locking”
• Difficulty straightening the knee fully
• Feeling as if the knee is “giving way”

Meniscus tears are diagnosed by a combination of a characteristic patient history, physical exam and MRI. The history of injury (if present) and the knee symptoms that the person is experiencing are important clues. When a meniscus tear is present, physical exam often reveals tenderness over the area of the torn meniscus and pain with provocative maneuvers for meniscus tears. A thorough knee exam is important to evaluate range of motion and assess the knee ligaments as well.

X-rays should be obtained to evaluate for the concomitant presence of knee arthritis and to evaluate for other maladies such as loose bodies.

MRI is the best noninvasive method for meniscus tear diagnosis. High quality MRIs have been shown to be quite accurate for the diagnosis of meniscus tears.

Nonsurgical treatments for meniscus tears are intended to relieve symptoms. The reason for this is that the great majority of meniscus tears do not have the capacity to heal.

Treatments to help relieve pain and other symptoms of meniscus tears involve such options as non-steroidal anti-inflammatory medications (NSAIDs), cortisone injections into the knee and modalities such as ice. Physical therapy and exercise regimens designed to strengthen the muscles around the knee have been shown to be helpful. Low impact and non-impact cardiovascular exercise (such as bike and elliptical type machines) are recommended.

Surgical treatment is typically undertaken for athletes and for people whose meniscus tear symptoms interfere with their quality of life despite nonsurgical treatment attempts. The surgical treatments are arthroscopic and thus minimally invasive. Aboard certified orthopaedic surgeon should perform the surgery. Sports medicine and knee orthopaedic surgery specialists typically perform these knee arthroscopies.

There are two ways that meniscus tears are treated surgically. If the meniscus tear is in the inner two-thirds of the meniscus where there is no blood supply, then the meniscus tear does not have the ability to heal. In this instance, the torn portion of the meniscus is removed with small instruments. This procedure is termed a partial meniscectomy. The procedure is viewed on a large viewing monitor since the arthroscope (camera) is placed in the knee through a very small incision. Since the great majority of tears reside in the portion of the meniscus that cannot heal, partial meniscectomy is the most common surgical treatment.

If the meniscus tear resides in the peripheral one-third of the meniscus where there exists a blood supply, then the tear has the capacity to heal. In this instance, the surgical treatment will likely be a repair of the meniscus to try to obtain healing. This is termed a meniscus repair. This surgery is still performed in a minimally invasive arthroscopic fashion. The tear can be repaired with sutures or a variety of commercial devices that have sutures attached to them.

The course after meniscus surgery depends on whether the meniscus tear undergoes repair or partial meniscectomy.

For the more common partial meniscectomy, the recovery is quite quick. People are allowed to bear weight as tolerated. However, most people use crutches for at least several days after the surgery due to discomfort. Most people are walking reasonably well by one week postoperative. It typically takes three to four weeks to return to most activities. Rehabilitation exercises are important in the early postoperative period.

For meniscus repair, the recovery period is longer because the repair needs to be protected to allow the meniscus to heal. Postoperative rehabilitation regimens vary quite a bit amongst surgeons. Most surgeons will use some form of brace for four to six weeks with some form of protected weight bearing. Physical therapy is important and progression to running is typically not allowed until ten to twelve weeks after surgery. Return to sports is typically geared toward four months postoperative.

The results of meniscus surgery are generally quite favorable. Partial meniscectomy allows athletes to return to many sports in five to six weeks. Middle-aged and elderly people may have arthritis in their knees in addition to meniscus tears. The extent of the arthritis often impacts the amount of relief these people will obtain from meniscus tear surgery.

Meniscus repair is often performed in younger athletes with traumatically induced meniscus tears. Although the meniscus is not one of the better healing structure in the body, athletes will most often heal these and return to their prior level of sports participation.