The meniscus is comprised of two c-shaped wedges of cartilage that cushion and stabilize the knee joint. A torn meniscus can cause pain and limited mobility in the knee.
Meniscus tears are extremely common knee injuries. 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 menisci 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. If the meniscus tears, the knee may lose its ability to remain stable and function effectively.
While meniscus tears may happen to anyone, they are often caused by playing sports, or a traumatic injury, and most frequently occur 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. Sports-related meniscal tears often occur along with other knee injuries, such as anterior cruciate ligament, or ACL, tears.
Causes of a Meniscus Tear
Meniscus tears usually occur during athletic events. They are most prevalent in sports involving direct contact, such as when tackling is taking place. Older adults are also at risk for having degenerative meniscus tears, since knee cartilage often weakens and wears away as a person ages, making the cartilage more vulnerable to tearing.
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 locking or grinding sensation felt during walking
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.
Recovery from a Meniscus Tear Procedure
Following surgery, the knee may be placed in a cast to keep it immobile. If the patient has undergone meniscus repair, crutches will likely be necessary for about one month. Once the knee has healed, the patient may need to take part in a physical therapy program to improve the range of motion of the joint. Meniscus repair usually requires a lengthier rehabilitation than meniscectomy, since the meniscus must heal back together after repair.
The recovery time following meniscus repair will be about 3 months, while recovery from meniscectomy is usually about 3 to 4 weeks. With proper rehabilitation, patients are often able to regain their full strength and return to all of their regular activities, including participation in sports.