Total knee replacement. Artwork of the bones and ligaments (right and left) surrounding an artificial (prosthetic) knee joint that has been surgically implanted to replace the existing knee. The patella (knee cap) has been removed, and the upper and lower parts of the implant cemented and drilled into the existing bones (the tibia, bottom; and the femur, top). The prosthetic knee joint, which is hinged to replicate the movement of a normal knee joint, is made from materials such as metal, plastic and bone ceramics. Total knee replacements are used for conditions such as osteoarthritis.