Abstract: A prosthesis suited for orthopedic implantation possesses a multi-piece stem component that supports an artificial joint surface that can articulate with another artificial joint surface in various ways. The prosthesis can be assembled in a snap fit and/or interlocking fashion that provides positive locking means without the use of screws or other fasteners. The prosthesis can accommodate fitment of a plastic joint surface made, e.g., from ultra high molecular weight polyethylene. The prosthesis is well suited for use in an ankle replacement system that can be installed using minimally invasive intramedullary guidance established with respect to the major axis of the tibia by minimally invasive access through the calcaneus, through an incision in the bottom of the foot. The prosthesis makes possible the installation of a total ankle system using minimally invasive anterior access to the ankle joint for making bony cuts and to install prosthesis components.