What is a Meniscus?

The meniscus is a fibrocartilaginous structure that exists as an important part of the medial and lateral weight-bearing compartment of the knee.

Anatomy

There are two menisci, the medial and lateral meniscus. The meniscus is named according to its location in either the medial or the lateral weight-bearing compartment. Each meniscus is a C shaped structure with attachments to the capsule and the tibia. The cross sectional shape of the meniscus is triangular with the base of the triangle situated peripherally and the apex centrally. The vascular supply to the meniscus derives from the periphery and penetrates the meniscus at its capsular attachment. The vessels terminate at the junction of the central and peripheral 1/3rd of the meniscus making the central 2/3rds avascular.

Physiology

The meniscus functions primarily to reduce the contact surface stress on the articular surfaces of the tibia and femur. The medial femoral condyle is a convex surface and the articulating medial tibia condyle is flat. Within this context, there is a physical mismatch and the contact surface stress becomes exceedingly high based on the limited contact area. The addition of the meniscus onto the flat surface of the tibia creates a concave surface, which now matches the convexity of the femoral condyle. Within this context, the contact surface stresses are reduced substantially based on the substantially increased contact surface area. This mismatch is even more pronounced in the lateral compartment of the knee where the lateral femoral condyle is a convex surface articulating on a convex tibial plateau.

The meniscus secondarily increases translational and rotational stability of the knee by creating a higher level of condylar conformity.

What Are Meniscus Tears?

Injuries involving the meniscus of the knee are quite common, perhaps the most common injury affecting the knee. A knee meniscus tear is a “rip” in the cartilage, or the main shock absorber of the knee joint, between the upper leg bone (femur or thighbone) and the shinbone (tibia) in the lower leg. Knee meniscus injuries can be divided into two categories: acute and chronic. Acute meniscal tears are caused by sudden, excessive forces on the knee, usually in a twisting motion. Chronic tears result from many, less severe injuries that accumulate over time. As you might imagine, acute meniscal tears are more common in young athletes who play high-intensity contact sports, while chronic tears are common in older people, usually those over the age of 40. Both acute and chronic meniscus tears should be evaluated by a torn meniscus doctor, such as an orthopedic surgeon.

Symptoms and Causes of Meniscus Tears

Degenerative tears may present as gradual onset knee pain or may present as more sudden onset pain. There may or not be knee effusion (swelling), difficulty weight bearing, loss of motion, locking or feelings of instability. Tears related to an injury are likely to have a relatively sudden onset of knee pain, more likely to have a knee effusion, difficulty weight bearing, loss of motion and feeling of instability and weakness.

In fact, many people with meniscus tears will report that their knee clicks, catches, locks, or “gives way” even before the pain starts. Because the pain is delayed, athletes may continue playing on the torn meniscus, at least on the same day as the injury occurred. A torn meniscus doctor can elicit other symptoms during examination. For example, the leg may not flex and extend normally during examination.

Acute meniscus tears usually occur in athletes. A person who deeply bends the knee and twists it at the same time is at risk for a torn meniscus. Direct trauma to the knee will also cause a meniscus tear, so it may occur during a football tackle, sports collision, or motor vehicle accidents. Chronic meniscus tears are more likely to occur in people with occupations that require them to squat or kneel frequently (carpet and tile layers, plumbers, miners, painters, etc.)

Associated Meniscus Tear Injuries

Degenerative tears may be associated with osteoarthritis or hyaline cartilage damage. Traumatic tears may be associated with ACL or other ligament tears, articular cartilage injury, bone contusions and other pathology. The diagnosis of a meniscus tear is confirmed with MRI imaging. This allows the knee to also be evaluated for possible associated injury.

Nonsurgical Treatments for Meniscus Tears

A torn meniscus will not heal on its own without surgery; however, some people with small meniscus tears may not undergo surgical meniscus tear treatment and still have relatively normal lives. Nonsurgical meniscus tear treatment includes PRICE: protection, rest, ice, compression, and elevation. PRICE is helpful for most knee injuries, including small meniscus tears. Nonsurgical meniscus tear treatment also includes over-the-counter pain medications such as nonsteroidal anti-inflammatory drugs or NSAIDs (e.g. ibuprofen, naproxen).  If these management strategies are ineffective the alternate surgical pathway can always be chosen with no permanent loss on the basis of a delay to surgery.

Surgical treatment is an arthroscopic procedure which is minimally invasive and involves introducing a camera inside of the knee with the ability to visualize and remove the torn portion of the meniscus. Degenerative meniscus tear are in large part not amenable to repair on the basis of their nature including poor tissue quality and avascular tear patterns. If you think you may have a torn meniscus and need meniscus tear treatment, it is best to speak with a local torn meniscus doctor in NYC, Staten Island, or Jersey City to help you decide.

Surgical Treatments for Meniscus Tears

Large meniscus tears, or those that interfere with the stability and function of the knee, usually require surgical meniscus tear treatment. These occur from an injury of some type such as from sports. They more often require surgery. The benefit of performing surgery on a traumatic meniscus tear, especially in a younger person, is the potential opportunity to repair the tear and restore the meniscus to its pre-injury capacity to function. Today, almost all surgical meniscus tear treatments are performed arthroscopically (joint surgery performed through small incisions using very thin instruments) and at iOrtho we prefer a technique of all-inside repair.

While you are under either general anesthesia or local anesthesia with intravenous sedation, your torn meniscus doctor will make three or four small incisions in the knee. These small incisions become portals through which an arthroscope and small instruments enter the knee joint. The damaged knee meniscus may be removed in a procedure called a partial meniscectomy. In other cases, the torn meniscus may be repaired by suturing the tear in the meniscus closed. This allows the surgeon to place the stitches arthroscopically without the need for an open incision in the back of the knee. Traumatic meniscus tears within the context of reduced tissue quality such as might be encountered in a degenerative knee may be initially treated using the nonsurgical pathway listed above.