Total knee replacement or total prosthesis of the knee or  (click to see the surgery) is very widespread: each year, in France alone, approximately 50.000 prosthesis are implanted (see the clinical result). The surgical procedure systematically replaces the cartilage between the femur and the tibia. During surgery, the femoral and tibial metal parts  are anchored to the bone: the plastic central part allows the movement between femur and tibia. This prosthesis is called "tricompartmental" (total knee replacement), (as opposed to the unicompartimental prosthesis or partial knee replacement  which replace only one compartment) because even the cartilage of the patella can be replaced - if necessary - by a patellar polyethylene button.