The menisci are cartilage structures in the knee joint that act as buffers between the bones. The menisci are vulnerable to injury, especially during twisting motions used for sports.
The knee joint is composed of three bones. The thigh bone (femur) sits on top of the larger leg bone (tibia). The kneecap (patella) glides in a groove on the end of the thigh bone. The menisci are two C-shaped cartilage discs that are located on the end of the tibia. The outer edges of the menisci have a blood supply, which can allow injuries to heal. The inner part of the menisci does not have a good blood supply, and tears in this area cannot heal on their own. The menisci help to support body weight and act as shock absorbers with walking or running. They also allow the knee bones to glide easily during motion.
The menisci can tear during strong twisting motions of the knee, especially when the foot remains firmly planted on the ground and the knee is bent. Pivoting, cutting, changing directions quickly, or slowing down quickly during sports, such as football, tennis, or soccer, can cause a meniscus tear. Older adults can experience a meniscus tear as the result of weakened cartilage and knee degeneration.
You may hear a popping noise when the meniscus tears. Swelling, pain, and tightness may increase over several days. You may not be able to straighten your knee, and it may buckle, catch, or lock in position. It may be difficult for you to put weight on your leg or walk.
Your doctor will review your medical history and conduct a physical exam. He or she will evaluate excess fluid and swelling around your knee joint. An X-ray may be used to see the condition of your bones. A magnetic resonance imaging (MRI) scan may be used to create a picture of your menisci and inner knee structures to help your doctor diagnose your injury.
Physical therapy can help strengthen the muscles that move the knee joint. Building strength and flexibility in your knee and legs may help prevent future degeneration in your knee. To control pain and swelling, your physical therapist may use ice and compression and will instruct you in the use of these treatments at home. Your physical therapist can also recommend a knee brace for sports or custom orthotics to support the arch of the foot.