Patent ID: 8231684

Claim:
A humeral head augment device for use in a shoulder prosthesis, the shoulder prosthesis including a humeral head having an articulation surface with at least one radius of curvature and a stem defining a longitudinal axis, wherein the humeral head is configured to couple to the stem such that a first articulation surface portion of a radius of curvature of the articulation surface extends at least across the longitudinal axis of the stem, the humeral head augment device comprising: an external bearing surface having at least two surface portions; and a coupling mechanism configured to connect the humeral head augment device in operable position within the shoulder prosthesis, the coupling mechanism connecting the humeral head augment device to at least one of the stem and the humeral head, wherein the at least two surface portions comprise a first bearing surface portion of a first radius of curvature and a second bearing surface portion of a second radius of curvature that is different from the first radius of curvature, wherein the first bearing surface portion is positioned adjacent the first articulation surface portion of the humeral head and the second bearing surface portion is positioned adjacent the first bearing surface portion when the humeral head and the humeral head augment device are operably positioned within the shoulder prosthesis, and wherein the first radius of curvature of the first bearing surface portion is greater than the radius of curvature of the first articulation surface portion at least immediately adjacent the first bearing surface portion to constrain translation of an implanted shoulder prosthesis when the humeral head augment device is employed in operable position within the implanted shoulder prosthesis.