Knee surgery is one of the most common orthopaedic surgeries performed in the United States. Usually, knee surgery is performed to relieve some painful or debilitating condition of the knee joint.

The knee is made up of a variety of structures that may become injured or worn. These include: the bones of the knee - the ends of the femur (thigh) and lower leg (tibia), and the kneecap (the patella); the patellar tendon, which completely envelops the patella dna connects the thigh muscles to the tibia; the ligaments - anterior cruciate (ACL) and medial collateral (MCL) which hold the bones together; and the meniscus (a cartilaginous cushion between the femur and tibia). Additionally, the ends of the femur and the patella are covered by cartilage (soft, cushiony tissue).

Any of these structures may become injured or worn and require knee surgery. Some of the more common conditions that may require knee surgery are: torn meniscus, degenerative arthritis, ruptured patellar tendon and torn or ruptured ligaments. If you suffer one of these conditions or injuries, your surgeon may recommend knee surgery, most commonly arthroscopic knee surgery.

During arthroscopic knee surgery, a series of very small incisions (cuts) are made in the skin around the knee, and various instruments are inserted through these cuts into the knee. Each of these instruments is long and narrow, about the diameter of a pencil. One of them is an "arthroscope" - a fiber optic camera with a light and a tiny camera that relays pictures from inside the knee to a television for the surgeon to look at while he operates the other instruments. Water can also be dispensed through the arthroscope to inflate the knee for better visualization or to clean it out as part of the knee surgery.

In arthroscopic knee surgery, the surgeon manipulates one or two other small instruments that can cut, grab or "deburr" (grind down) worn or damaged tissues. This is what happens during knee surgery for a torn meniscus or degenerative arthritis, for example. For reconstructive knee surgeries, to repair a torn ACL or patellar tendon, for instance, the surgeon can also tie the ends of damaged soft tissues (ligaments, for example) together to repair the knee.

One type of knee surgery that always involves a full incision is "total knee replacement." In this surgery, the damaged ends of the knee bones are cut down and a titanium cap is glued over them to provide a smooth contact surface between the femur and tibia.

All of these types of knee surgery are generally followed by a rehabilitative program that helps the knee to regain strength.