A sterile implantable artificial substitute for a knee joint typically designed to replace all the articulating surfaces of the joint [total knee arthroplasty (TKA)] because of major loss of stabilizing structures or bone around the knee, often from tumour resection, or to replace a dysfunctional knee prosthesis (revision); it is designed with a mechanism for joint rotation and its major components are connected for stability typically about a transverse axis posterior of the rotational axis. It typically includes femoral, tibial, and patellar components that articulate and with parts made of metal, ceramic, and/or polyethylene (PE); it may be implated with or without bone cement.