A knee prosthesis kit includes an implant and an augment. The implant has a base and a stem extending from the base, and the augment has a base and a conical, cylindrical, or anatomic portion extending from the base. The augment base has at least two openings for receiving fasteners for securing the knee augment to the implant. The portion and the base define a bore for receipt of the implant post. A coupler includes a mating portion for receipt in a bore of an implant post, and a cone-shaped portion extending from the mating portion. A method of providing fixation of knee implants includes securing an augment to an implant and positioning a conical, cylindrical, or anatomic portion of the augment within the intramedullary canal of the tibia or femur.