A meniscal tear is a rupturing of one or more of the fibrocartilage strips in the knee called menisci. When doctors and patients refer to “torn cartilage” in the knee, they actually may be referring to an injury to a meniscus at the top of one of the tibiae. Menisci can be torn during innocuous activities such as walking or squatting. They can also be torn by traumatic force encountered in sports or other forms of physical exertion. The traumatic action is most often a twisting movement at the knee while the leg is bent. In older adults, the meniscus can be damaged following prolonged ‘wear and tear’ called a degenerative tear.
Tears can lead to pain and/or swelling of the knee joint. Especially acute injuries (typically in younger, more active patients) can lead to displaced tears which can cause mechanical symptoms such as clicking, catching, or locking during motion of the knee joint. The joint will be in pain when in use, but when there is no load, the pain goes away.
A tear of the medial meniscus can occur as part of the unhappy triad, together with a tear of the anterior cruciate ligament (ACL) and medial collateral ligament (MCL).
The common signs and symptoms of a torn meniscus are knee pain and swelling. These are worse when the knee bears more weight (for example, when running). Another typical complaint is joint locking, when the affected person is unable to straighten the leg fully. This can be accompanied by a clicking feeling. Sometimes, a meniscal tear also causes a sensation that the knee gives way.
A person with a torn meniscus can sometimes remember a specific activity during which the injury was sustained. A tear of the meniscus commonly follows a trauma which involves rotation of the knee while it was slightly bent. These maneuvers also exacerbate the pain after the injury; for example, getting out of a car is often reported as painful.
The Cooper’s sign is present in over 92% of tears. It is a subjective symptom of pain in the affected knee when turning over in bed at night. Osteoarthritic pain is present with weightbearing, but the meniscal tear causes pain with a twisting motion of the knee as the meniscal fragment gets pinched, and the capsular attachment gets stretched causing the complaint of pain.
There are two menisci in the knee. They sit between the thigh bone (femur) and the shin bone (tibia). While the ends of the thigh bone and the shin bone have a thin covering of soft hyaline cartilage, the menisci are made of tough fibrocartilage and conform to the surfaces of the bones they rest on. One meniscus rests on the medial tibial plateau; this is the medial meniscus. The other meniscus rests on the lateral tibial plateau; this is the lateral meniscus.
These menisci act to distribute body weight across the knee joint. Without the menisci, the weight of the body would be unevenly applied to the bones in the legs (the femur and tibia). This uneven weight distribution would cause the development of abnormal excessive forces leading to early damage of the knee joint. The menisci also contribute to the stability of the joint.
The menisci are nourished by small blood vessels but have a large area in the center with no direct blood supply (avascular). This presents a problem when there is an injury to the meniscus, as the avascular areas tend not to heal. Without the essential nutrients supplied by blood vessels, healing cannot take place.
The two most common causes of a meniscal tear are traumatic injury (often seen in athletes) and degenerative processes, which are the most common tear seen in all ages of patients. Meniscal tears can occur in all age groups. Traumatic tears are most common in active people aged 10–45 and are usually radial or vertical in the meniscus and more likely to produce a moveable fragment that can catch in the knee and therefore require surgical treatment.
Degenerative tears are most common in people from age 40 upward but can be found at any age, especially with obesity. Degenerative meniscal tears are thought to occur as part of the aging process when the collagen fibers within the meniscus start to break down and lend less support to the structure of the meniscus. Degenerative tears are usually horizontal, producing both an upper and a lower segment of the meniscus. These segments do not usually move out of place and are therefore less likely to produce mechanical symptoms of catching or locking.
X-ray images (normally during weightbearing) can be obtained to rule out other conditions or to see if the patient also has osteoarthritis. The menisci themselves cannot be visualised with plain radiographs. If the diagnosis is not clear from the history and examination, the menisci can be imaged with magnetic resonance imaging (an MRI scan).
Tear of a meniscus is a common injury in many sports. The menisci holds 30–50% of the body load in standing position. Some sports where a meniscus tear is common are football and soccer. Regardless of what the activity is, it is important to take the correct precautions to prevent a meniscus tear from happening.
There are three major ways of preventing a meniscus tear. The first of which is wearing the correct footwear for the sport and surface that the activity is taking place on. This means that if the sport being played is soccer, cleats are an important item in reducing the risk of a meniscus tear. The proper footwear is imperative when engaging in physical activity because one off balanced step could mean a meniscus tear.
The second way to prevent a meniscus tear is to strengthen and stretch the major leg muscles. Those muscles include the hamstrings, quadriceps, and calf muscles. Adequate muscle mass and strength may also aid in maintaining healthy knees.
The last major way to prevent a tear in the meniscus is learning proper technique for the movement that is taking place. For the sports involving quick powerful movements it is important to learn how to cut, turn, land from a jump, and stop correctly. It is important to take the time to perfect these techniques when used. These three major techniques will significantly prevent and reduce the risk of a meniscus tear.
Initial treatment may include physical therapy, bracing, anti-inflammatory drugs, or corticosteroid injections to increase flexibility, endurance, and strength.
Exercises can strengthen the muscles around the knee, especially the quadriceps. Stronger and bigger muscles will protect the meniscus cartilage by absorbing a part of the weight. The patient may be given paracetamol or anti-inflammatory medications or biomechanical interventions such as Apos Therapy. For patients with non-surgical treatment, physical therapy program is designed to reduce symptoms of pain and swelling at the affected joint. This type of rehabilitation focuses on maintenance of full range of motion and functional progression without aggravating the symptoms. Physical therapists can utilize modalities such as electric stimulation, cold therapy and ultrasonography, etc.
Arthroscopy is a surgical technique in which a joint is operated on using an endoscopic camera as opposed to open surgery on the joint. The meniscus can either be repaired or completely removed, this is described in further detail below. It should not be recommended for a degenerative meniscus tear, unless there is locking or catching of the knee, recurrent effusion or persistent pain. Evidence supports that it is no better than conservative management in those without osteoarthritis. Additionally there does not appear to be any benefit in those with a tear of the meniscus and mild arthritis who are adults.
If a person fails to improve after trying these treatments, then arthroscopy should be considered. Patients who additionally have osteoarthritis may require surgical options.
If the injury to the meniscus is isolated, then the knee would be relatively stable. However, if another injury such as a Anterior cruciate ligament injury (torn ACL) was coupled with a torn meniscus, then an arthroscopy would be performed. A meniscal repair has a higher success rate if there is an adequate blood supply to the peripheral rim. The interior of the meniscus is avascular, but the blood supply can penetrate up to about 6 millimeters or a quarter inch. Therefore, meniscus tears that occur near the peripheral rim are able to heal after a meniscal repair. A study conducted found that it is better to repair the meniscus rather than remove it (meniscectomy). The amount of rehabilitation time required for a repair is longer than a meniscectomy, but removing the meniscus can cause osteoarthritis problems. If the meniscus is removed, the patient will be in rehab for about four to six weeks. If a repair is conducted, then the patient will need four to six months. If physical therapy does not resolve the symptoms, or in cases of a locked knee, then surgical intervention may be required. Depending on the location of the tear, a repair may be possible. In the outer third of the meniscus, an adequate blood supply exists and a repair will likely heal. Usually younger patients are more resilient and respond well to this treatment, while older, more sedentary patients do not have a favorable outcome after a repair.
Meniscus transplants are accomplished successfully regularly, although it is still somewhat of a rare procedure. Side effects of meniscectomy include:
• The knee loses its ability to transmit and distribute load and absorb mechanical shock.
• Persistent and significant swelling and stiffness in the knee.
• The knee may be not be fully mobile, there may be the sensation of knee locking or buckling in the knee.
• The full knee may be in full motion after tear of meniscus
After a successful surgery for treating the destroyed part of the meniscus, patients must follow a rehabilitation program to have the best result. The rehabilitation following a meniscus surgery depends on whether the entire meniscus was removed or repaired.
If the destroyed part of the meniscus was removed, patients can usually start walking using a crutch a day or two after surgery. Although each case is different, patients return to their normal activities on average after a few weeks (2 or 3). Still, completely normal walk will resume gradually and it’s not unusual to take 2–3 months for the recovery to reach a level where a patient will walk totally smoothly. Many meniscectomy patients don’t ever feel a 100% functional recovery, but even years after the procedure they sometimes feel tugging or tension in a part of their knee.
If the meniscus was repaired, the rehabilitation program that follows is a lot more intensive. After the surgery a hinged knee brace is sometimes placed on the patient. This brace allows controlled movement of the knee. The patient is encouraged to walk using crutches from the first day, and most of the times can put partial weight on the knee.
Improving symptoms, restoring function, and preventing further injuries are the main goals when rehabilitating. By the end of rehabilitation, normal range of motion, function of muscles and coordination of the body are restored. Personalized rehabilitation programs are designed considering the patient’s surgery type, location repaired (medial or lateral), simultaneous knee injuries, type of meniscal tear, age of patient, condition of the knee, loss of strength and range of motion, and the expectations and motivations of the patient.