Patella prosthesis having rotational and translational freedom

Abstract

A patellar prosthesis includes an articulation component having a prosthetic articulation surface and a base component for fixation to resected patellar bone. Each of the articulation and base components include planar bearing surfaces in sliding engagement. The base component includes a fixed pin extending perpendicularly from its respective planar bearing surface. The articulation component includes an elongate groove in its respective planar bearing surface. The pin and groove have complementary wall profiles that provide for an elastic snap-retention of the pin within the groove. The articulation component is free to rotate about the axis of the pin received within the groove, and is free to translate parallel to the planar bearing surfaces, limited by the length of the groove. The articulation component enjoys only one rotational degree of freedom, and only two translational degrees of freedom. For any determined rotational orientation, translation is limited to one degree of freedom, parallel to the length of the groove. The articulation component is free to rotate about the pin at any point along the length of the groove.

Dependencies are inferred from the claim text.