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Definition of «Injury, knee meniscus»

Injury, knee meniscusInjury, knee meniscusInjury, knee meniscusInjury, knee meniscus

Injury, knee meniscus: Injury to one of the two crescent-shaped cartilage pads between the two joints formed by the femur (the thigh bone) and the tibia (the shin bone). Each meniscus acts as a smooth surface for the joint to move on.

The two menisci are easily injured by the force of rotating the knee while bearing weight. A partial or total tear of a meniscus may occur when a person quickly twists or rotates the upper leg while the foot stays still (for example, when dribbling a basketball around an opponent or turning to hit a tennis ball). If the tear is tiny, the meniscus stays connected to the front and back of the knee; if the tear is large, the meniscus may be left hanging by a thread of cartilage. The seriousness of a tear depends on its location and extent.

Generally, when people injure a meniscus, they feel some pain, particularly when the knee is straightened. The pain may be mild, and the person may continue activity. Severe pain may occur if a fragment of the meniscus catches between the femur and tibia. Swelling may occur soon after injury if blood vessels are disrupted, or swelling may occur several hours later if the joint fills with fluid produced by the joint lining (synovium) as a result of inflammation. If the synovium is injured, it may become inflamed and produce fluid to protect itself. This causes swelling of the knee. Sometimes, an injury that occurred in the past but was not treated becomes painful months or years later, particularly if the knee is injured a second time. After any injury the knee may click, lock, or feel weak. Symptoms of meniscal injury may disappear on their own but frequently, symptoms persist or return and require treatment.

In addition to listening to the patient's description of the onset of pain and swelling, the physician may perform a physical examination and take x rays of the knee. The examination may include a test in which the doctor flexes (bends) the leg then rotates the leg outward and inward while extending it. Pain or an audible click suggests a meniscal tear. An MRI test may be recommended to confirm the diagnosis. Occasionally, the doctor may use arthroscopy to help diagnose and treat a meniscal tear.

If the tear is minor and the pain and other symptoms go away, the doctor may recommend a muscle-strengthening program. Exercises for meniscal problems are best performed with initial guidance from a doctor and physical therapist or exercise therapist. The therapist will make sure that the patient does the exercises properly and without risk of new or repeat injury. The following exercises after injury to the meniscus are designed to build up the quadriceps and hamstring muscles and increase flexibility and strength:

  • Warming up the joint by riding a stationary bicycle, then straightening and raising the leg (but avoiding straightening the leg too much).
  • Extending the leg while sitting (a weight may be worn on the ankle for this exercise).
  • Raising the leg while lying on the stomach.
  • Exercising in a pool, including walking as fast as possible in chest-deep water, performing small flutter kicks while holding onto the side of the pool, and raising each leg to 90 degrees in chest-deep water while pressing the back against the side of the pool.

If the tear to a meniscus is more extensive, the doctor may perform either arthroscopic surgery or open surgery" to see the extent of injury and to repair the tear. The doctor can suture (sew) the meniscus back in place if the patient is relatively young, the injury is in an area with a good blood supply, and the ligaments are intact. Most young athletes are able to return to vigorous sports with meniscus-preserving repair.

If the patient is elderly or the tear is in an area with a poor blood supply, the doctor may cut off a small portion of the meniscus to even the surface. In some cases, the doctor removes the entire meniscus. However, degenerative changes, such as osteoarthritis, are more likely to develop in the knee if the meniscus is removed. Medical researchers are currently investigating a procedure called an allograft, in which the surgeon replaces the meniscus with one from a cadaver. A grafted meniscus is fragile and may shrink and tear easily. Researchers have also attempted to replace a meniscus with an artificial one, but the procedure is even less successful than an allograft.

Recovery after surgery to repair a meniscus takes several weeks longer and post-operative activity is slightly more restricted than when the meniscus is removed. Nevertheless, putting weight on the joint actually fosters recovery. Regardless of the form of surgery, rehabilitation usually includes walking, bending the legs, and doing exercises that stretch and build up the leg muscles. The best results of treatment for meniscal injury are obtained in people who do not show articular cartilage changes and who have an intact anterior cruciate ligament.

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