You’re chasing your kids around the yard when suddenly you feel a “pop” in your knee. Or you’re playing basketball and twist your body (and knee) too quickly while your feet are on the ground. The pain comes immediately, and not long after, your knee becomes swollen and stiff. And when you bend it, it feels as if something is “catching,” especially if you twist or squat. Your doctor refers you to an orthopaedist, who in turn, diagnoses the problem: a torn meniscus.

Meniscus tears are among the most common knee injuries, and though they occur more often in men, they can affect people of any age and sex. Fortunately, treatments are available for meniscus injuries. They include both conservative, nonsurgical therapies, as well as several types of surgeries.

“Treatment for meniscus tears should be individualized to each patient and be based on the patient’s age, activity level, and the overall condition of the articular cartilage in the knee joint, whether a patient has underlying arthritis or not,” says Christina Allen, MD, chief of Yale Medicine Orthopaedics & Rehabilitation Sports Medicine and head team physician for Yale Athletics.  

There are two menisci (the plural of meniscus) in each knee—one on the lateral (outer) side of the knee, and one on the medial (inner) side. Each meniscus is a thin, “c”-shaped disc of rubbery tissue made of cartilage that is attached to the top of the tibia, or shinbone. The meniscus sits between the tibia and the end of the femur (thighbone), where it functions as a shock absorber between these bones and also contributes to the stability of the knee.

The meniscus is one of two types of cartilage in the knee joint. The other is called articular cartilage, which covers the ends of the tibia, femur bone, and kneecap (patella).

In young, healthy people, meniscus tears often happen as a result of an injury in which the knee rotates or twists while the foot is planted. This kind of injury is known as an acute meniscus tear. It frequently occurs when playing sports such as soccer, football, and basketball that involve pivoting and sharp changes of direction.  

Meniscus tears can also occur when a leg is struck with force while the foot is planted or when lifting a heavy weight. In some cases, meniscus tears are accompanied by injuries to the articular cartilage or ligaments in the knee, such as the anterior cruciate ligament (ACL) and/or the medial collateral ligament (MCL).

In middle-aged and older people, meniscus injuries tend to be degenerative meniscus tears. As people age, the cartilage in the knee, including the meniscus, begins to wear down. As a result, the meniscus becomes more susceptible to injury. Degenerative meniscus tears may occur from everyday activities that do not entail a lot of physical twisting of the knee, such as squatting, planting the foot and turning, or even climbing stairs.

Meniscus tears can occur in various parts of the meniscus and can vary in severity. The majority of meniscal injuries occur in the medial (inner) meniscus, though injuries can also involve the lateral (outer) meniscus.

Depending on its severity, a torn meniscus can cause a variety of symptoms, including the following:

• Knee pain, which may worsen when twisting or bending the knee or squatting
• Swelling overnight following the initial injury
• A “popping” sensation at the time of injury
• Knee-locking, in which the leg cannot fully straighten
• A sensation that the knee is “catching” or "popping" when bending
• The knee “gives out” or feels somewhat unstable
• Stiffness

In some cases, meniscal tears do not produce any symptoms.  

To diagnose meniscus injuries, doctors assess the patient’s medical history, perform a physical exam, and run diagnostic tests.

As an initial step, doctors typically collect information about the patient’s injury history, asking about knee pain and other symptoms, recent physical activity, and whether the patient can point to a specific acute knee injury that initiated symptoms.

During the physical exam, the doctor will check the knee for swelling, pain, and tenderness. The doctor will bend and flex the knee to evaluate range of motion, assess knee ligament stability, and feel for "clicking" or "popping" with meniscus tear tests. He or she may observe the patient’s gait and ask the patient to perform a squat, a “duck walk,” or to stand on the affected leg and twist on it, which may reproduce the meniscus tear symptoms.

In most cases, the doctor will also order an X-ray of the patient’s knee. Sometimes, doctors will order a magnetic resonance imaging (MRI) study to detect injuries and determine the extent of the meniscal damage.

In some cases, diagnosis of a meniscus tear requires arthroscopy, a minimally invasive surgical procedure in which a surgeon makes one or two small incisions on the knee, then inserts an arthroscope (a tiny pencil-sized tube equipped with a camera) and surgical instruments into the knee. The camera captures a video of the inside of the knee, allowing the surgeon to examine structures and tissues, including the meniscus.

There are two general forms of treatment for meniscus tears: conservative, or nonsurgical, and surgical. The choice of treatment depends on several factors, including severity of the tear and which part of the meniscus is damaged, as well as the patient’s age, overall health, physical activity level, and overall condition of the knee joint.

Nonsurgical Treatment. Many meniscus tears do not require surgery. For instance, small meniscus tears or degenerative meniscus tears, in particular in people older than 50, are often treated without surgery. Studies have shown that older patients who have underlying articular cartilage wear (arthritis) in the knee do poorly with arthroscopic meniscus surgery and that the arthroscopic surgery may actually speed up the development of knee arthritis.

Nonsurgical treatment may involve the following:

• Resting the knee
• Applying ice to the knee for 15 minutes every one or two hours to reduce swelling
• Keeping the knee elevated to reduce swelling
• Taking over-the-counter anti-inflammatory medications such as Ibuprofen to reduce swelling and pain
• Avoiding sports and activities that cause pain or involve twisting or bending the knee
• Using crutches if everyday activities, such as walking, cause knee pain
• Using a knee brace if the knee feels unstable or the patient has underlying arthritis (unloader brace)

In many cases, doctors will refer patients to a physical therapist to restore range of motion and strength. Under the guidance of a physical therapist, patients perform exercises that strengthen the quadriceps and other muscles around the knee joint and hip with the aim of building strength, improving knee stability and balance, and maintaining or increasing range of motion.

In addition, if the patient has underlying osteoarthritis in the knee (i.e., articular cartilage is worn down to the bone), the doctor may offer to inject the patient with a cortisone or viscosupplementation injection to reduce pain and swelling.

Surgical Treatment. If the meniscus tear is severe or if conservative treatment does not produce the desired results, surgery may be required. Several surgical procedures are used to treat meniscus tears, most of which are done arthroscopically.

• Meniscectomy, a term that means excision, or trimming, of the meniscus. There are two types of meniscectomy:
  • Partial Meniscectomy: The surgeon trims away the damaged portion of the meniscus, leaving as much healthy tissue intact as possible. This is the most common surgical treatment for a torn meniscus. Patients can typically return to sports and other physically demanding activities within six to eight weeks of a partial meniscectomy with proper physical therapy after surgery.
    
    
  • Total or subtotal Meniscectomy: The surgeon removes the entire meniscus or most of it. Whenever possible, partial meniscectomy is preferred to total meniscectomy because removal of the entire meniscus elevates the risk of developing osteoarthritis. Sometimes, however, a total or subtotal meniscectomy is the best or only option when the meniscus tear is large and unrepairable.

• Meniscal Repair. In this procedure, the surgeon stitches the torn meniscus together. It is more commonly used in younger patients in which the torn meniscus tissue is in good condition and the tear is a “clean” (not shredded) pattern and close to the blood supply, which will allow the meniscus to heal. Repairs may be performed “all inside” with small meniscus repair devices to pull the tear together, or “inside out,” in which sutures are passed across the tear and through the knee joint capsule and then tied through an incision next to the tear (usually for larger meniscus tears). Full recovery from meniscal repair surgery can take four to six months based on the tear pattern, the patient’s baseline activity level, and his or her level of dedication to physical therapy.

• Meniscal Transplantation. People under the age of 50 who have a damaged meniscus that needs to be completely removed or who have previously had their meniscus removed via a total meniscectomy may be candidates for meniscal transplantation. In this procedure, a surgeon inserts a meniscus from a cadaver (a donor) into the patient’s knee joint. (The donor meniscus has to be matched to the patient’s knee prior to surgery based on measurements from their knee MRI.) The donor meniscus provides shock absorption in the knee and may help prevent the development of osteoarthritis in younger patients who lack a meniscus. In patients who have undergone ACL reconstruction surgery, the medial (inside) meniscus is a very important structure to protect the ACL graft. Occasionally, surgeons will perform an ACL reconstruction or revision (re-do) ACL reconstruction in combination with medial meniscus transplantation to protect the ACL graft and prevent ACL graft overload.

In general, with proper treatment and rehabilitation, people who experience meniscus tears, especially older patients, are often able to go back to their normal activities. Still, meniscus tears may increase the risk of developing osteoarthritis, and if left untreated, they can worsen over time.  

However, although meniscectomy is likely to remove pain and "catching" symptoms in an active patient, there is no guarantee that they will not develop osteoarthritis over time due to the loss of some of the shock-absorbing property of the meniscus due to partial removal.

“At Yale Sports Medicine, our surgeons will assess each patient’s history, activity level, knee injury, and activity goals in order to advise them on an individualized treatment plan. Our goal is to treat the patient—not their MRI—and to suggest the best treatment option to allow them to return to their desired activity level while aiming to protect their long-term knee health in the best way possible,” says Dr. Allen. “Whether this means recommending non-operative treatment with physical therapy and cortisone injection, performing a meniscus trimming or repair, or surgically inserting a meniscus transplant of the medial or lateral meniscus, our Sports Medicine surgeons have the skills and expertise to advise and treat patients with these goals in mind.”