Metallic implants having roughened surfaces and methods for producing the same

Abstract

The invention provides a method of providing a metallic orthopaedic implant with a micron or nanometer-scale surface roughness to facilitate acceptance of tissue and bone growth or apposition after implantation while maintaining the structural integrity of the orthopaedic implant. The invention also provides a metallic orthopaedic implant comprising a metallic body and metallic elements adhered to a portion of the surface of the metallic body to define a three-dimensional porous surface geometry, wherein at least some of the metallic elements have a micron or nanometer-scale surface roughness.

What is claimed is:  
     
         1 . A method of providing a metallic orthopaedic implant with a micron or nanometer-scale surface roughness to facilitate acceptance of tissue and bone growth or apposition after implantation while maintaining the structural integrity of the orthopaedic implant, which method comprises the steps of: 
 (a) providing a metallic orthopaedic implant comprising a metallic body having a surface and metallic elements adhered to at least a portion of the surface of the metallic body to define a three-dimensional porous surface geometry,    (b) exposing at least a portion of the surface and metallic elements to an etching solution comprising (i) at least one fluoride salt, (ii) at least one acid, and (iii) water for a time and under conditions sufficient to provide the implant with micron or nanometer-scale surface roughness while maintaining structural integrity of the orthopaedic implant,    (c) cleaning at least the portion of the surface and metallic elements exposed to the etching solution, and    (d) drying the metallic orthopaedic implant.    
     
     
         2 . The method of  claim 1 , wherein the etching solution further comprises a sulfate salt.  
     
     
         3 . The method of  claim 1 , wherein the concentration of the fluoride salt is about 0.1 to about 3 wt. % of the etching solution, and the concentration of the acid in the etching solution is about 0.1 to about 2 N.  
     
     
         4 . The method of  claim 2 , wherein the concentration of the fluoride salt is about 0.1 to about 3 wt. % of the etching solution, the concentration of the sulfate salt is about 0.5 to about 5 wt. % of the etching solution, and the concentration of the acid in the etching solution is about 0.1 to about 2 N.  
     
     
         5 . The method of  claim 1 , wherein the metallic body comprises a metal selected from the group consisting of titanium, titanium alloys, tantalum, tantalum alloys, stainless steel, and cobalt chromium alloy.  
     
     
         6 . The method of  claim 1 , wherein the fluoride salt is selected from the group consisting of ammonium fluoride, copper fluoride, potassium fluoride, sodium fluoride, zinc fluoride, and mixtures thereof.  
     
     
         7 . The method of  claim 1 , wherein the acid is selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, lactic acid, perchloric acid, oxalic acid, tartaric acid, phosphoric acid, and mixtures thereof.  
     
     
         8 . The method of  claim 2 , wherein the sulfate salt is selected from the group consisting of aluminum sulfate, ammonium sulfate, copper sulfate, iron sulfate, lithium sulfate, magnesium sulfate, nickel sulfate, potassium sulfate, sodium sulfate, and mixtures thereof.  
     
     
         9 . The method of  claim 1 , wherein the metallic elements comprise metallic particles.  
     
     
         10 . The method of  claim 9 , wherein the metallic particles comprise metallic beads.  
     
     
         11 . A metallic orthopaedic implant comprising (i) a metallic body having a surface and (ii) metallic elements adhered to a portion of the surface of the metallic body to define a three-dimensional porous surface geometry, wherein at least some of the metallic elements are interconnected to provide pores of 10 μm or more diameter between adjacent metallic elements, and wherein at least some of the metallic elements have a micron or nanometer-scale surface roughness.  
     
     
         12 . The metallic orthopaedic implant of  claim 11 , wherein the metallic body comprises a metal selected from the group consisting of titanium, titanium alloys, tantalum, tantalum alloys, stainless steel, and cobalt chromium alloy.  
     
     
         13 . The metallic orthopaedic implant of  claim 11 , wherein the metallic elements comprise metallic particles.  
     
     
         14 . The metallic orthopaedic implant of  claim 13 , wherein the metallic particles comprise metallic beads.  
     
     
         15 . The metallic implant of  claim 11 , wherein the surface of the metallic orthopaedic implant further comprises at least one bioactive coating.  
     
     
         16 . The metallic implant of  claim 15 , wherein the bioactive coating is selected from the group consisting of calcium phosphate, bioactive glasses, glass ceramics, biopolymers, extracted proteins, recombinant proteins, peptides, and mixtures thereof.  
     
     
         17 . A method of providing a metallic orthopaedic implant having a native oxide surface layer with a micron or nanometer-scale surface roughness to facilitate acceptance of tissue and bone growth or apposition after implantation while maintaining the structural integrity of the orthopaedic implant, which method comprises the steps of: 
 (a) providing a metallic implant having a native oxide surface layer and at least a portion thereof to be altered to provide a micron or nanometer-scale surface roughness,    (b) exposing the portion of the surface layer to an etching solution comprising (i) at least one fluoride salt, (ii) at least one acid, and (iii) water for a time and under conditions sufficient to provide the implant with the micron or nanometer-scale surface roughness while maintaining structural integrity of the orthopaedic implant,    (c) cleaning at least the exposed surface, and    (d) drying the metallic orthopaedic implant.    
     
     
         18 . The method of  claim 17 , wherein the etching solution further comprises a sulfate salt.  
     
     
         19 . The method of  claim 17 , wherein the concentration of the fluoride salt is about 0.1 to about 3 wt. % of the etching solution, and the concentration of the acid in the etching solution is about 0.1 to about 2 N.  
     
     
         20 . The method of  claim 18 , wherein the concentration of the fluoride salt is about 0.1 to about 3 wt. % of the etching solution, the concentration of the sulfate salt is about 0.5 to about 5 wt. % of the etching solution, and the concentration of the acid in the etching solution is about 0.1 to about 2 N.  
     
     
         21 . The method of  claim 17 , wherein the metallic implant comprises a metal selected from the group consisting of titanium, titanium alloys, tantalum, tantalum alloys, stainless steel, and cobalt chromium alloy.  
     
     
         22 . The method of  claim 17 , wherein the fluoride salt is selected from the group consisting of ammonium fluoride, copper fluoride, potassium fluoride, sodium fluoride, zinc fluoride, and mixtures thereof.  
     
     
         23 . The method of  claim 17 , wherein the acid is selected from the group consisting of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, lactic acid, perchloric acid, oxalic acid, tartaric acid, phosphoric acid, and mixtures thereof.  
     
     
         24 . The method of  claim 18 , wherein the sulfate salt is selected from the group consisting of aluminum sulfate, ammonium sulfate, copper sulfate, iron sulfate, lithium sulfate, magnesium sulfate, nickel sulfate, potassium sulfate, sodium sulfate, and mixtures thereof.