The knee can bend and straighten in a smooth and fluid fashion thanks to the cartilage on the ends of the thigh bone (femur) and leg bone (tibia). This cartilage is similar to the smooth shiny surface on the end of a chicken bone. There is also another type of cartilage in the knee called the meniscus. The meniscus is localized between the ends of the bones and acts as a shock absorber and stabilizer. It is a very important structure, because studies have shown that if the entire meniscus is removed, the knee can develop arthritis.
How it happens
The meniscus is frequently injured in sports and also when lifting weights in the gym. The most common mechanism of injury is a rapid twisting of the knee, but it can occur many other ways such as a forceful flexion. This can happen if a lifter hits the deep full squat position hard and bounces back up. In some cases, you may not remember a specific injury, but the meniscus can tear due to repetitive loads and chronic cartilage degeneration.
How it feels
A torn meniscus is often painful because loose ends of the torn piece can get trapped in the knee. In some cases, the torn piece can lead to mechanical catching or locking of the knee and you will have to maneuver the knee to “unlock” it and allow motion. In other cases, a piece of the meniscus can break off and become a “loose body” that can also lead to the knee catching or locking. Magnetic Resonance Imaging (MRI) is very helpful to confirm the diagnosis and can assist in determining the best course of treatment for the meniscus tear.
How it is fixed
After the onset of symptoms, a trial of physical therapy and anti-inflammatory medications may be warranted. However, mechanical symptoms such as catching and locking will only resolve if the offending fragment of meniscus tissue is removed. This is done with arthroscopic surgery. The procedure is performed through two small holes in the knee, each measuring less than a centimeter. A camera is inserted into the knee through one hole and surgical instruments through the other. The torn pieces from the knee are removed with the surgical instruments. To avoid future problems with the knee, as little tissue as possible is removed. In some cases, the meniscus can be repaired so no tissue is removed. We see our work inside the knee live on a television screen in the operating room. The fiber optics allows a better view of the inside of the knee than can be achieved with open surgery.
Following the meniscus surgery, rehabilitation is undertaken with a physical therapist. The initial steps in therapy are to reduce swelling and regain full motion of the knee. Crutches are generally used for a few days and most patients are walking normally by one to two weeks following surgery. Strengthening is an important part of the rehabilitation process and return to sports is generally possible by three months. Professional athletes who are in top shape and can dedicate each day to rehabilitation can return to play within a week or two in some cases, depending on their sport.