A system for long bone arthroplasty includes humeral head prosthesis components, and an array of humeral head prosthesis components, each humeral head prosthesis component in the array having a convex articulation surface that is hemi-elliptical and defined by a major axis, a minor axis, an apex, and a base having an elliptical cross sectional shape defined by a major diameter along the major axis and a minor diameter along the minor axis, wherein the array of elliptical humeral head prosthesis components provides for suitable and sufficient anatomical fit within a variation of up to and not more than 3 mm in at least 96% of a patient population, and up to 99% of a patient population.