Prosthesis with surfaces having different textures and method of making the prosthesis

Abstract

A joint prosthesis system is suitable for cementless fixation. The system has two metal implant components and a bearing. One of the metal implant components has an articulation surface for articulation with the bearing. The other metal implant component has a mounting surface for supporting the bearing. One of the metal implant components includes a solid metal portion and a porous metal portion. The porous metal portion has surfaces with different characteristics, such as roughness, to improve bone fixation, ease removal of the implant component in a revision surgery, reduce soft tissue irritation, improve the strength of a sintered bond between the solid and porous metal portions, or reduce or eliminate the possibility of blood traveling through the porous metal portion into the joint space. A method of making the joint prosthesis is also disclosed. The invention may also be applied to discrete porous metal implant components, such as augments.

1 - 67 . (canceled) 
     
     
         68 . A tibial implant component comprising a bearing and a tibial tray, the tibia tray having a solid metal portion and a porous metal portion, the solid metal portion including a proximal surface to receive the bearing and a distal surface, the porous metal portion having a void space and including a proximal surface along the distal surface of the solid metal portion and an exposed distal bone-engaging surface, the tibial tray having an exposed peripheral surface extending around at least a portion of the periphery of the tibial tray, wherein:
 the exposed peripheral surface is generally perpendicular to and extends from the level of the exposed distal bone-engaging surface of the porous metal portion toward the solid metal portion;   the exposed peripheral surface has a static coefficient of friction; and   the exposed distal bone-engaging surface has a higher static coefficient of friction than the exposed peripheral surface.   
     
     
         69 . The tibial implant component of  claim 68  wherein the exposed peripheral surface is distal to the distal surface of the solid metal portion. 
     
     
         70 . The tibial implant component of  claim 68  wherein the exposed peripheral surface comprises porous metal extending from the exposed distal bone-engaging surface of the porous metal portion to the distal surface of the solid metal portion. 
     
     
         71 . The tibial implant component of  claim 68  wherein the porous metal portion has a void space of at least 60% by volume. 
     
     
         72 . The tibial implant component of  claim 68  wherein the exposed peripheral surface extends around the entire periphery of the tibial tray and includes porous metal around the entire periphery of the tibial tray. 
     
     
         73 . The tibial implant component of  claim 68  wherein the porous metal portion comprises metal foam. 
     
     
         74 . The tibial implant component of  claim 72  wherein the metal foam includes titanium.