What is a Meniscus Tear?

The meniscus is a C-shaped cartilage structure in the knee that sits between the tibia (leg bone) and the femur (thigh bone).· Once thought a remnant of development, the meniscus is now recognized to play a crucial role in the normal knee’s health, including joint transmission forces, shock absorption, nutrition and lubrication.· There are two menisci in each knee, one medial (inside) and one lateral (outside).

Meniscus tears are one of the most common orthopedic injuries, most commonly occurring on the medial (inside) of the knee.

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How does it occur?

• Most meniscus tears occur with a twisting, turning or squatting maneuver.· In the younger athletic population, there may be an acute pop and pain at the time of the injury, either by itself, or associated with a ligament injury (most commonly the ACL).· As one ages, degenerative changes within the substance of the meniscus render it vulnerable to tearing with trivial activities. Sometimes just stepping off a curb, out of a car or on the tennis court can be sufficient to tear the cartilage pad.

Risk increases with:

• Aggressive sports that involved pivoting, cutting and squatting.
• Contact sports (football), sports in which cleats are used with pivoting (soccer) or sports in which good shoe grip and sudden change in direction are required (racquetball, basketball, squash)
• Previous knee injury
• Associated knee injury, particularly ligament injuries
• Poor physical conditioning (strength and flexibility)

What are the symptoms of a meniscus tear?

• Pain, especially when standing on the affected leg and squatting, and tenderness along the joint of the knee
• Swelling of the affected knee, usually starting 1 to 2 days after the injury (may occur right after the injury)
• Locking or catching of the knee joint, causing an inability to straighten the knee completely
• Giving way or buckling of the knee

How is a meniscus tear diagnosed?

• Physical exam shows focal tenderness along the joint line of the respectively torn meniscus

• Pain with forced flexion

• Pain with McMurray Test (in which the knee is flexed and rotated internally and externally), often reproducing pain and/or clunking sensation

Are there any special tests?

X-rays are unhelpful. Patients often present with symptoms and physical findings that are diagnostic of a meniscus tear, and won’t require further testing. When indicated, the diagnostic test of choice is an MRI (Magnetic Resonance Imaging), which permits visualization of the menisci (as well as other knee joint structures including soft tissue ligaments, articular cartilage and bone).· MRI reliability is over 90% in detecting meniscus tears.

How is a meniscus tear treated?

Non-operative treatment: Initial treatment consists of medications and ice to relieve pain and reduce the swelling of the affected joint. Sometimes walking with crutches until you walk without a limp is recommended (you may put full weight on the injured leg). Range-of-motion, stretching and strengthening exercises may be carried out at home, although referral to a physical therapist or athletic trainer may be recommended.

Splint or brace

Your physician may recommend a brace, immobilizer or crutches to protect the joint. The predominant treatment of meniscus tear is activity modification, avoiding those activities that provoke symptoms. The duration of modifying activities depends upon many factors, including the degree of impairment, the type of activity, patient demand, tear size, etc.

Operative treatment

Surgery is often recommended as definitive treatment and is performed arthroscopically. Most of the time the torn fragment is removed, smoothing the remainder.· The meniscus tear often looks like a piece of crabmeat and acts like a hang nail, intermittently caught and entrapped in the joint.· Most meniscal tears are treated arthroscopically with resection of the torn fragment.

Infrequently, meniscus tears may be repairable, preserving the meniscus by placement of devices or sutures that literally mend the torn cartilage.· However, repairs are very uncommon because most of them do not satisfy the criteria for repair.· Repairable tears are those that are located near the blood supply in the periphery (site of meniscus attachment to the capsule of the knee), are unstable (can be displaced into the joint with a probe), are longitudinal (torn parallel to the joint contour, rather than radial or in a cleavage plane), and are healthy (not degenerative and/or torn in multiple planes).

Surgery for meniscal tears is reserved for people who have symptomatic tears of the meniscus, including locking, recurrent swelling and giving way of the knee, and for those for whom conservative treatment of the tear has failed. Occasionally, it is also recommended for patients with pain along the knee joint where the meniscus is. It is also recommended for those with displaced tears that prevent full knee range of motion (“locked knee”), which is a sign of a “bucket handle” tear. A bucket handle tear is when the meniscus tears and flips to the center of the knee, like moving a bucket handle from one side of the bucket to the other.

Surgery is performed electively, but locked knees should be operated on at the earliest convenient time. The success of meniscus repair has not been shown to be any better immediately after injury as compared with a couple of months later. Only the outer 10 percent to 30 percent of the meniscus cartilage has blood supplying it. Blood is needed to help a meniscus heal. Because of this, fewer than 20 percent of all meniscus tears are repairable by suturing (sewing) it together. The rest of the tears are treated by meniscectomy (removal of all or part of the meniscus). A torn meniscus usually does not heal itself, unless the tear is in the outer portion of the meniscus where the blood supply is. Thus, most tears do not heal on their own. Further, meniscus cartilage that is removed does not regenerate. Once removed, it is gone.

The success of meniscus repair (healing of the tear) is about 80 percent in knees with an intact anterior cruciate ligament (ACL). However, meniscus repair when the ACL is torn and not reconstructed is successful only 40 percent of the time. If the meniscus tear is repairable, most surgeons also recommend reconstructing the ACL. The age of the patient has no effect on healing of a repair.

Because one function of the meniscus is to distribute joint forces, loss of meniscus cartilage is associated with the early development of arthritis of the knee joint. The goal of meniscal surgery is to eliminate the symptoms in your knee while trying to save as much of the meniscus cartilage as possible. This would be by repairing the meniscus, if possible, or removing as little of the meniscus as possible. Removing all or part of a torn meniscus allows for contouring of the cartilage and removal of the torn edges that prevent progression of the tear (making a smaller tear larger) and displacement of the tear, causing recurrence of symptoms of locking, giving way and swelling.

Leaving a torn meniscus in the knee if it does not cause symptoms is usually not a problem. However, torn meniscus cartilage does not function and thus the development of arthritis or symptoms such as locking, swelling and giving way still may occur. Further, tears may progress to become larger if left untreated.

Arthroscopy has become the standard way of operating on meniscal tears. This is done on an outpatient basis (you go home the same day) and may be done under general anesthesia, spinal anesthesia or local anesthesia. Small shavers and cutting instruments are used to remove and contour torn cartilage that is not repairable. For tears that are repairable, the edges of the tear are freshened; then sutures (to sew), anchors or tacks are used to hold the torn edges together while the meniscus heals.

What are the complications of treatment?

Possible complications of non-operative treatment include:

• Persistent symptoms
• Athletic and daily activity impairment
• Arthritis is not a typical consequence of neglected meniscus tears
• Tear extension is possible if a tear is neglected and the patient continues to subject the knee to stresses

Possible complications of operative treatment include:

• Surgical complications not specifically associated with knee arthroscopy, such as pain, bleeding (uncommon), infection (<1 percent), nerve injury (uncommon), stiffness, problems with anesthesia, and inability to return to previous level of pre-injury activity. 

Complications specific to surgical treatment of this condition: 

• Persistent pain, typically in patients with more than just a meniscus tear. The most common patient who fails to improve is one in whom the tear is but one component of their presentation, such as an individual with arthritis and worn joint surfaces, particularly when in the compartment in which the meniscus is torn. 
• Progressive symptoms may occur in those patients in which a significant portion of the meniscus requires removal.· This is particularly true in patients who undergo a substantial meniscectomy in their lateral (outside of the knee) compartment. 

When can you return to your sport or activity?

Some meniscal injuries can heal on their own, and some do not heal but may not cause any symptoms. However, the only definitive treatment for meniscal tears requires surgery. It may take six weeks before sports can be resumed after meniscectomy (although possibly as early as two to three weeks) or as long as six to nine months after a meniscus repair. After surgery or immobilization, stretching and strengthening of the injured, stiff and weakened joint and surrounding muscles are necessary. These may be done with or without the assistance of a physical therapist or athletic trainer. Return to sports depends on the type of sport and the position played and full knee motion and strength are necessary before sports can be resumed. 

How can a meniscus tear be prevented?

• Appropriately warm up and stretch before practice or competition
• Maintain appropriate conditioning:
  • Thigh, knee, and leg strength
  • Flexibility and endurance
• For jumping sports (basketball, volleyball) or contact sports, protect vulnerable joints with supportive devices, such as wrapped elastic bandages, tape or braces (these have not been proven effective).
• Wear proper protective equipment and ensure correct fit, including proper cleats for the surface