Patent ID: 7485147
Filing Date: 2009-02-03
Classification: A61F

Abstract:
1. An improved prosthetic joint of the type including: a first platform having a first bearing surface, the first platform being configured for being secured to a first bone of an anatomical joint; a second platform having a substantially planar second bearing surface facing towards the first platform, the second platform being configured for being secured to a second bone of the anatomical joint; a bearing insert having a third bearing surface slidably engaged with the first bearing surface of the first platform for sliding movement relative thereto during joint articulation, the bearing insert further having a fourth bearing surface slidably engaged with the second bearing surface of the second platform to permit rotation of the bearing insert relative to the second platform about an axis normal to the second bearing surface, the bearing insert providing an articulated joint between the first platform and the second platform; means for constraining motion of the bearing insert during joint articulation to a predetermined path relative to the first platform; wherein the improvement comprises: a peripheral wall extending from said second bearing surface and about said bearing insert to shield the bearing insert from contacting anatomical tissue for reducing the formation of bone cysts, the peripheral wall defining an inner periphery that is dimensioned relative to the bearing insert for permitting translation between the bearing insert and the second bearing surface defined on the second platform in directions parallel to the second bearing surface, and wherein all of the bearing insert is within a projection of the peripheral wall from the second bearing surface towards the first platform and wherein all cross sections through the bearing insert and parallel to the second bearing surface are smaller than the second bearing surface.