A system for performing surgery on a femur and tibia of a knee joint. The system includes a robotic subsystem； a navigation subsystem in communication with the robotic subsystem； a control unit in communication with the robotic subsystem； and a display in communication with the control unit. The navigation subsystem provides the robotic subsystem with information relating to positions of the femur and tibia thereby enabling their separate tracking when the femur and tibia move during surgery. The navigation subsystem cooperates with the robotic subsystem to determine a position of the cutting tool relative to the femur and tibia to guide movement of the cutting tool to cut away material from the femur and tibia. The control unit receives information relating to the position of the cutting tool such that movement of the cutting tool relative to the femur and tibia during surgery is viewable on the display.
