The meniscus is a piece of cartilage in the knee that cushions and stabilizes the joint, protecting the bones from wear and tear. Each knee has two menisci, one on the inside (medial) and one on the outside (lateral) of the knee. The meniscus acts as a shock absorber and provides a smooth surface for the knee to glide on. It also transmits the load of your weight evenly across the knee joint. Meniscus tears are common knee injuries that can occur when the knee is sharply pivoted or rotated, or when an athlete twists or turns their upper leg while their foot is planted and their knee is bent. Symptoms of a meniscus tear include pain, swelling, a popping sensation, difficulty bending and straightening the leg, and a tendency for the knee to get "stuck" or lock up. Knee arthroscopy is often used to treat meniscal tears, which is a minimally invasive procedure where a small, lighted, optic tube (arthroscope) is inserted through a small incision in the joint. Images of the inside of the knee are then projected on a screen allowing the provider to repair or trim out the torn portion of the meniscus.