The knee is the meeting place of upper and lower leg bones held together by flexible ligaments. The important portion of the knee includes the bones, joints (cartilage), ligaments, tendons, muscles, nerves, and blood vessels. The bones, cartilage, muscles, ligaments, and tendons help the knees perform motions like walking, running, crouching, jumping, and turning.
When the knee is injured by accident or by diseases, one or more of the important parts of the knee is damaged, knee replacement may be necessary. If x-rays and other tests show joint damage; moderate-to-severe, persistent pain does not improve adequately with non-surgical treatment; and the limited range of motion in the knee joint diminishes the quality of life patient will require total knee replacement.
A thin layer of bone is removed from the damaged surface of the femur (thigh bone) using special instruments that remove the correct thickness of bone. The removed bone is then replaced by a thin layer of metal, approximately the same thickness as the removed bone. Similarly, the upper end of the tibia (shin bone) is removed and replaced with a thin sandwich of metal and plastic. The back part of the knee cap (patella) is also resurfaced with a wafer of plastic.