Orthopedic implants and methods

Abstract

A prosthesis for replacing a natural articular surface on a bone may have a joint facing side with an articular surface, a bone anchoring side with a bone engagement surface, and a bone engagement pad secured to at least part of the bone engagement surface. The bone engagement pad may have a transverse portion extending transverse to a length of the bone, and one or more protruding portions extending generally perpendicular to the transverse portion. The transverse portion may have a pad bone-facing surface with a first porosity level, and a pad joint-facing surface on an opposite side of the transverse portion from the pad bone-facing surface, with a second, lower porosity level. The bone engagement surface may be formed via a first manufacturing process selected from the group consisting of forging, milling, and casting. The bone engagement pad may be formed via an additive manufacturing process.

What is claimed is: 
     
         1 . A knee implant for replacing a natural articular surface on bone, the knee implant comprising:
 a joint facing side comprising an articular surface shaped to replace the natural articular surface, wherein the natural articular surface is one of a natural tibial articular surface and a natural femoral articular surface;   a bone anchoring side comprising a bone engagement surface; and   a bone engagement pad secured to at least part of the bone engagement surface, the bone engagement pad comprising:
 a transverse portion extending transverse to a length of the bone, the transverse portion comprising:
 a pad bone-facing surface comprising a first porosity level; and 
 a pad joint-facing surface on an opposite side of the transverse portion from the pad bone-facing surface, the pad joint-facing surface comprising a second porosity level lower than the first porosity level; and 
 
 one or more protruding portions extending generally perpendicular to the transverse portion; 
   wherein:
 the bone engagement surface is formed via a first manufacturing process selected from the group consisting of forging, milling, and casting; 
 the bone engagement pad is formed via a second manufacturing process different from the first manufacturing process; and 
 the second manufacturing process is an additive manufacturing process. 
   
     
     
         2 . The knee implant of  claim 1 , wherein:
 the bone engagement pad extends generally transverse to a length of the bone, and has a thickness, parallel to the length, that is substantially uniform; and   the thickness is within the range of 0.5 mm to 1.5 mm.   
     
     
         3 . The knee implant of  claim 1 , wherein:
 the bone engagement surface comprises a bone engagement feature extending through an aperture formed in the transverse portion; and   the one or more protruding portions extend from one or more edges of the aperture, alongside one or more surfaces of the bone engagement feature.   
     
     
         4 . A prosthesis for replacing a natural articular surface on bone, the prosthesis comprising:
 a joint facing side comprising an articular surface;   a bone anchoring side comprising a bone engagement surface; and   a bone engagement pad secured to at least part of the bone engagement surface, the bone engagement pad comprising:
 a pad bone-facing surface comprising a first porosity level; and 
 a pad joint-facing surface comprising a second porosity level lower than the first porosity level. 
   
     
     
         5 . The prosthesis of  claim 4 , wherein:
 the bone engagement surface is formed via a first manufacturing process; and   the bone engagement pad is formed via a second manufacturing process different from the first manufacturing process.   
     
     
         6 . The prosthesis of  claim 5 , wherein:
 the first manufacturing process is selected from the group consisting of forging, milling, and casting; and   the second manufacturing process is an additive manufacturing process.   
     
     
         7 . The prosthesis of  claim 4 , wherein the bone engagement pad has a thickness within the range of 0.5 mm to 1.5 mm. 
     
     
         8 . The prosthesis of  claim 4 , wherein:
 the bone engagement pad comprises a transverse portion that extends generally transverse to a length of the bone;   the pad bone-facing surface and the pad joint-facing surface are on opposite sides of the bone engagement pad; and   the transverse portion has a thickness, parallel to the length, that is substantially uniform.   
     
     
         9 . The prosthesis of  claim 4 , wherein the bone engagement pad comprises:
 a transverse portion extending transverse to a length of the bone, wherein the pad bone-facing surface and the pad joint-facing surface are on opposite sides of the transverse portion; and   one or more protruding portions extending generally perpendicular to the transverse portion.   
     
     
         10 . The prosthesis of  claim 9 , wherein:
 the bone engagement surface comprises a bone engagement feature extending through an aperture formed in the transverse portion; and   the one or more protruding portions extend from one or more edges of the aperture, alongside one or more surfaces of the bone engagement feature.   
     
     
         11 . The prosthesis of  claim 4 , wherein:
 the bone engagement pad comprises a transverse portion that extends generally transverse to a length of the bone;   the pad bone-facing surface and the pad joint-facing surface are on opposite sides of the bone engagement pad; and   the transverse portion comprises a porosity gradient by which porosity of the transverse portion gradually increases toward the pad bone-facing surface.   
     
     
         12 . The prosthesis of  claim 4 , wherein:
 the bone engagement pad comprises a transverse portion that extends generally transverse to a length of the bone;   the pad bone-facing surface and the pad joint-facing surface are on opposite sides of the bone engagement pad; and   the transverse portion comprises a low-porosity layer proximate the pad joint-facing surface, by which a porosity of the transverse portion abruptly increases toward the pad bone-facing surface.   
     
     
         13 . The prosthesis of  claim 4 , wherein:
 the prosthesis comprises a knee implant;   the articular surface is shaped to replace the natural articular surface; and   the natural articular surface is one of a natural tibial surface and a natural femoral articular surface.   
     
     
         14 . A prosthesis for replacing a natural articular surface on bone, the prosthesis comprising:
 a joint facing side comprising the articular surface;   a bone anchoring side comprising a bone engagement surface; and   a bone engagement pad secured to at least part of the bone engagement surface, the bone engagement pad comprising:
 a transverse portion extending transverse to a length of the bone; and 
 one or more protruding portions extending generally perpendicular to the transverse portion. 
   
     
     
         15 . The prosthesis of  claim 14 , wherein:
 the bone engagement surface is formed via a first manufacturing process; and   the bone engagement pad is formed via a second manufacturing process different from the first manufacturing process.   
     
     
         16 . The prosthesis of  claim 15 , wherein:
 the first manufacturing process is selected from the group consisting of forging, milling, and casting; and   the second manufacturing process is an additive manufacturing process.   
     
     
         17 . The prosthesis of  claim 14 , wherein the bone engagement pad has a thickness within the range of 0.5 mm to 1.5 mm. 
     
     
         18 . The prosthesis of  claim 14 , wherein the transverse portion extends generally transverse to a length of the bone, and has a thickness, parallel to the length, that is substantially uniform. 
     
     
         19 . The prosthesis of  claim 14 , wherein:
 the bone engagement surface comprises a bone engagement feature extending through an aperture formed in the transverse portion; and   the one or more protruding portions extend from one or more edges of the aperture, alongside one or more surfaces of the bone engagement feature.   
     
     
         20 . The prosthesis of  claim 14 , wherein:
 the prosthesis comprises a knee implant;   the articular surface is shaped to replace the natural articular surface; and   the natural articular surface is one of a natural tibial surface and a natural femoral articular surface.