Knee surgery is the most common joint replacement procedure done in the United States: as many as 400,000 people undergo some type of knee replacement surgery each year. Of that population, approximately 130,000 people undergo total knee replacement surgery, also known as total knee arthroplasty.
The surgery usually involves replacing the entire surface covering the ends of the thighbones and lower leg bones as a means to create new joint surfaces. Metal alloy and plastic polyethylene components are used to resurface the bones in the joint. The two surfaces at the end of the thighbone known as condyles are replaced and recreated. The top of the tibia (shinbone) are covered with a metal tray supporting a polyethylene plastic bearing. The femoral component also is attached to the plastic bearing in the back of the kneecap. The bearing takes the place of the joint’s natural cartilage, which absorbs stress and allows for smooth and flexible movement.