The largest joint in the body, the knee is made up of the lower end of the thighbone (femur), the upper end of the shinbone (tibia), and the kneecap (patella). The ends of these bones, where they touch, are covered with articular cartilage, a smooth substance that protects the bones and enables them to move easily. Between the femur and tibia are C-shaped wedges, called menisci, that act as shock absorbers to cushion the joint. Large ligaments holding the femur and tibia together provide stability and long thigh muscles give the knee strength. All remaining surfaces of the knee are covered by a thin lining, or synovial membrane, that releases fluid to lubricate the cartilage, reducing friction to nearly zero in a healthy knee. Normally, these components work together in harmony, but when disrupted by disease or injury the result can be pain, muscle weakness and reduced function.
Meniscal tears are among the most common knee injuries. Although anyone, at any age, can tear a meniscus, athletes, particularly those who play contact sports, are at increased risk. Menisci tear in different ways and often occur with other knee injuries, such as ACL tears. A tear is noted according to how it looks and where it is in the meniscus. Common tears include longitudinal, parrot-beak, flap, bucket handle, and mixed/complex.
When tearing a meniscus, you may hear a "popping" noise. Most people can still walk on the injured knee, and athletes often continue to play immediately following a tear. However, without proper treatment, a piece of meniscus may come loose and drift into the joint, worsening symptoms. During the next 2 to 3 days after tearing a meniscus, the knee will gradually become increasingly stiff, swollen and painful. Other common symptoms include: a sensation of the knee giving out from under you; catching, or locking, of the knee; and inability to move the knee through its full range of motion.
Sudden meniscal tears often occur during sports, as a player squats and twists the knee, or as a result of direct contact, such as a tackle. A degenerative meniscal tear is more likely in older patients because cartilage wears thin and weakens over time, making it more prone to tearing. Something as simple as an awkward twist may cause a tear if the tissue is weakened with age.
Your physician will examine the structures of your knee, checking for tenderness along the joint line, which can signify a tear. Your physician may bend and twist the knee or perform other special tests to evaluate for a tear of the meniscus. However, other knee problems may cause similar symptoms so your doctor may order imaging tests to help confirm the diagnosis. Magnetic resonance imaging (MRI) may be used to view the soft tissues of the knee joint more clearly. X-rays may also be taken to reveal osteoarthritis or injury to the bone that may be causing knee pain.
Your orthopaedic surgeon will provide treatment according to the type, size and location of your tear, also taking into consideration your age, activity level and any related injuries.
The outside one-third of the meniscus has a rich blood supply, so a tear on the outer edge of the meniscus may heal on its own, without surgical repair. As long as symptoms do not persist and your knee remains stable, nonsurgical treatment may be all that is needed. Rest, ice, compression (using a bandage), and elevation—or R.I.C.E., as the protocol is often referred to—are effective for most sports-related injuries. Nonsteroidal anti-inflammatory medication like aspirin and ibuprofen can also be used to help reduce pain and swelling.
The inner two-thirds of the meniscus lacks a blood supply. Without the nutrients supplied by blood, tears in this area cannot heal on their own. These complex tears often occur in thin, worn cartilage. The pieces cannot grow back together so tears in this zone are usually trimmed away surgically. Wherever your tear occurs, your orthopaedic surgeon may recommend arthroscopic surgery if your symptoms persist with nonsurgical treatment.
Knee arthroscopy is a minimally invasive surgical procedure used by orthopaedic surgeons to visualize, diagnose and treat problems inside the joint. In general, recovery from an arthroscopic procedure is quicker and less painful than recovery from traditional, open surgery.
After surgery, your orthopaedic surgeon may put your knee in a brace to keep it from moving. Once initial healing is complete, a program of exercise or physical therapy may be prescribed to restore your mobility and strength. With proper diagnosis, treatment and rehabilitation, patients are often able to return to all their normal activities. However, the time needed for recovery varies according to the patient, the condition of the joint, and the extent of damage and repairs required. For all patients, following the guidelines and rehabilitation plan of your orthopaedic surgeon is vital to a successful outcome.
As with any surgery, there are risks associated with knee arthroscopy. These occur infrequently and are typically minor and treatable. Potential postoperative problems include infection, blood clots and accumulation of blood in the knee.
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