The meniscus is a C-shaped piece of tough cartilage located in the knee, that acts as a shock absorber between the shinbone and the thighbone. There are two minisci within each knee. The meniscus on the inside part of the knee is known as the medial meniscus and the meniscus located on the outside of the knee is referred to as the lateral meniscus. A meniscus tear may be the result of an activity that forcefully twists or rotates the knee. A torn meniscus is a common knee injury that may be caused by playing sports, or a traumatic injury, and most frequently occurs when the knee joint is bent and the knee is then twisted. Torn menisci are common in athletes, but in some cases this condition may occur in older adults whose cartilage has worn away, as a result of many years of wear and tear of the joint.
Symptoms of a Meniscus Tear
Meniscus tears are usually defined by a distinctive popping or clicking sensation when the injury occurs. Most people will still be able to walk or play a sport using their injured knee, but the knee typically becomes swollen and stiff within a few days. The most common symptoms of meniscus tears include:
- Persistent pain whenever the knee is moved or twisted
- Inability to fully straighten the knee
A torn meniscus may also be accompanied by joint that frequently locks in place and the inability to completely straighten the knee.
Diagnosis of a Meniscus Tear
A meniscus tear is typically diagnosed after a complete evaluation of the patient's symptoms is conducted and a medical history obtained. The knee will be examined for tenderness along the joint line, which usually signifies the presence of a meniscus tear.
Several diagnostic tests will generally follow to confirm the tear. One commonly used evaluation tool is the McMurray test, in which the knee is bent, straightened and moved around in a circular fashion by the doctor. The circular motion places added tension on the meniscus and causes an audible clicking sound, enabling the doctor to diagnose the tear. Imaging tests, such as X-rays or an MRI or CT scan, may also be needed to obtain a view of the torn meniscus.
Treatment for a Meniscus Tear
If left untreated, a meniscus tear may result in a portion of the cartilage becoming loose and moving into the joint, causing the knee to slip out of place. Treatment usually depends on the severity of the tear and its exact location. Initial treatment methods for meniscus tears are generally conservative, such as placing ice on the knee, taking anti-inflammatory medications and elevating the knee to reduce swelling.
If symptoms continue despite these conservative measures, surgery may be necessary. Minimally invasive knee arthroscopy is one of the most commonly performed procedures to treat the condition. During this procedure, a flexible tube with a camera known as an arthroscope is inserted into the knee through a small incision. Small surgical instruments will be used to perform either a meniscus repair, which focuses on suturing the torn edges of the meniscus together to promote healing, or a meniscectomy, during which damaged meniscal tissue is trimmed away.
Physical therapy may also be effective at strengthening the muscles that support the knee joint. If these treatments are not effective and symptoms continue, meniscus repair surgery may be recommended. Meniscus repair is an arthroscopic surgery performed by orthopedic surgeons to remove the torn segment of the meniscus. The torn edges are then sutured together, which allows them to heal properly. Recovery from meniscus repair surgery can take several months of immobilization and the use of crutches. A physical therapy program is also effective after surgery to strengthen muscles and help the patient regain full mobility.