Abstract: A proximal humeral prosthesis includes a humeral head having a distal end and a proximal end adapted to be coupled to a glenoid cavity of a scapula; a humeral stem core having an outer surface, a distal end, and a proximal end adapted to be coupled to the distal end of the humeral head; a humeral stem graft having an inner surface adapted to be coupled to at least a portion of the outer surface of the humeral stem core, a distal end, a proximal end, and an outer surface including at least one tendon attachment site; and an intramedullary stem having a proximal end adapted to be coupled to the distal end of the humeral stem core and a distal end adapted to be coupled to at least one bone of a skeleton. The prosthesis can be rendered modular and can further include a spacer segment. Resorption of bone from the humeral stem graft can be inhibited by compression of the humeral stem graft.