An abutment system for operatively coupling an implant stem to an exo-prosthesis, the implant stem configured for positioning within a prepared site of a selected bone and surrounding soft tissue of a subject, the abutment system having a common longitudinal axis, the abutment system comprising: a plurality of interlocking sleeve elements, an end cap configured for engagement with the distal sleeve element of the plurality of sleeve elements, and a base element configured for operative coupling to the implant stem; wherein the plurality of sleeve elements comprises a proximal sleeve element and a distal sleeve element, the proximal sleeve element of the plurality of sleeve elements being configured for operative coupling to the implant stem, each sleeve element of the plurality of sleeve elements configured for selective, removable engagement with adjacent sleeve elements of the plurality of sleeve elements; wherein the proximal sleeve element of the plurality of sleeve elements is configured for engagement with the base element; wherein the end cap has a proximal portion and a distal portion, the distal portion of the end cap defining a distal end of the end cap, the distal end of the end cap being configured for engagement with the exo-prosthesis; wherein the base element has a flange and an elongate shaft, the flange having a first surface, an opposed second surface, and an outer edge extending between the first and second surfaces, the first surface of the flange defining a proximal end of the base element, the proximal end of the base element configured for operative coupling to the implant stem, the elongate shaft extending from a central portion of the flange away from the proximal end of the base element relative to the common longitudinal axis of the abutment system, and wherein each sleeve element of the plurality of sleeve elements defines a central bore configured for receipt of the elongate shaft of the base element, and wherein the proximal sleeve element of the plurality of sleeve elements being configured for engagement with the flange of the base element, and wherein the proximal and distal portions of the end cap have respective outer surfaces. a plurality of interlocking sleeve elements, an end cap configured for engagement with the distal sleeve element of the plurality of sleeve elements, and a base element configured for operative coupling to the implant stem; wherein the plurality of sleeve elements comprises a proximal sleeve element and a distal sleeve element, the proximal sleeve element of the plurality of sleeve elements being configured for operative coupling to the implant stem, each sleeve element of the plurality of sleeve elements configured for selective, removable engagement with adjacent sleeve elements of the plurality of sleeve elements; wherein the proximal sleeve element of the plurality of sleeve elements is configured for engagement with the base element; wherein the end cap has a proximal portion and a distal portion, the distal portion of the end cap defining a distal end of the end cap, the distal end of the end cap being configured for engagement with the exo-prosthesis; wherein the base element has a flange and an elongate shaft, the flange having a first surface, an opposed second surface, and an outer edge extending between the first and second surfaces, the first surface of the flange defining a proximal end of the base element, the proximal end of the base element configured for operative coupling to the implant stem, the elongate shaft extending from a central portion of the flange away from the proximal end of the base element relative to the common longitudinal axis of the abutment system, and wherein each sleeve element of the plurality of sleeve elements defines a central bore configured for receipt of the elongate shaft of the base element, and wherein the proximal sleeve element of the plurality of sleeve elements being configured for engagement with the flange of the base element, and wherein the proximal and distal portions of the end cap have respective outer surfaces.