Monolithic orthopedic implant with an articular finished surface

• US 8,556,972 B2
• Filed: 07/01/2010
• Issued: 10/15/2013
• Est. Priority Date: 04/02/2009
• Status: Expired due to Fees

• Current Assignee: Catharon Products Intellectual Property, LLC (Fred DuFresne)
• Original Assignee: Sevika Holding AG
• Inventors: Fisher, Michael G., Johnson, Paul R., Johannaber, Kenneth D., Gordon, Jeffrey D.
• Primary Examiner(s): Sweet, Thomas J
• Assistant Examiner(s): Prone, Christopher D
• Application Number:
  US12/829,095
• Publication Number:
  US 20100268337A1
• Time in Patent Office: 1,202 Days
• Field of Search: 623 2372- 76, 623/16.11
• US Class Current: 623/16.11
• CPC Class Codes: A61C 2008/0046 Textured surface, e.g. roughness, microstructure A61C8/0013 takes precedence
• CPC Class Codes: A61F 2/02 Prostheses implantable into the body closure means for urethra or rectum or for artificial body openings therefor A61F2/0004
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30 Joints
• CPC Class Codes: A61F 2/30756 Cartilage endoprostheses A61F2/3603 takes precedence
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2002/0086 for preferentially controlling or promoting the growth of specific types of cells or tissues of bone tissue onto implantable joints A61F2002/3093
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30062 (bio)absorbable, biodegradable, bioerodable, (bio)resorbable, resorptive
• CPC Class Codes: A61F 2002/30205 conical
• CPC Class Codes: A61F 2002/30207 Double convex cones, i.e. element having two convex cones, one at each of its opposite ends
• CPC Class Codes: A61F 2002/30214 having tapered sections of different conicities
• CPC Class Codes: A61F 2002/30215 Stepped cones, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30233 Stepped cylinders, i.e. having discrete diameter changes
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30301 saddle-shaped
• CPC Class Codes: A61F 2002/3065 Details of the ball-shaped head
• CPC Class Codes: A61F 2002/30655 Non-spherical concave inner surface
• CPC Class Codes: A61F 2002/30759 Mosaicplasty, i.e. using a plurality of individual cartilage plugs for filling a substantial cartilage defect
• CPC Class Codes: A61F 2002/30766 : Scaffolds for cartilage ingrowth and regeneration
• CPC Class Codes: A61F 2002/30878 : with non-sharp protrusions, for instance contacting the bone for anchoring, e.g. keels, pegs, pins, posts, shanks, stems, struts
• CPC Class Codes: A61F 2002/3092 : having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/3093 : for promoting ingrowth of bone tissue
• CPC Class Codes: A61F 2002/30934 : Special articulating surfaces
• CPC Class Codes: A61F 2210/0004 : bioabsorbable
• CPC Class Codes: A61F 2230/0067 : conical
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0095 : Saddle-shaped
• CPC Class Codes: A61F 2250/0023 : differing in porosity
• CPC Class Codes: A61F 2310/00161 : Carbon; Graphite
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00574 : Coating or prosthesis-covering structure made of carbon, e.g. of pyrocarbon
• CPC Class Codes: A61F 2310/0058 : Coating made of diamond or of diamond-like carbon DLC
• CPC Class Codes: A61F 2310/00592 : Coating or prosthesis-covering structure made of ceramics or of ceramic-like compounds
• CPC Class Codes: A61F 2310/00796 : Coating or prosthesis-covering structure made of a phosphorus-containing compound, e.g. hydroxy(l)apatite
• CPC Class Codes: A61F 2310/00928 : Coating or prosthesis-covering structure made of glass or of glass-containing compounds, e.g. of bioglass
• CPC Class Codes: A61F 2310/00976 : Coating or prosthesis-covering structure made of proteins or of polypeptides, e.g. of bone morphogenic proteins BMP or of transforming growth factors TGF
• CPC Class Codes: B29C 44/00 : Shaping by internal pressure generated in the material, e.g. swelling or foaming ; Producing porous or cellular expanded plastics articles
• CPC Class Codes: Y10T 29/49995 : Shaping one-piece blank by removing material
• CPC Class Codes: Y10T 428/24942 : including components having same physical characteristic in differing degree
• CPC Class Codes: Y10T 428/24992 : Density or compression of components

Abstract

A monolithic material including a first region having a first variability of strength and a second region joined to the first region, the second region having a second variability of strength, wherein the monolithic material has a variability of strength less than the first variability of strength of the first region and less than the second variability of strength of the second region.

Claims

1. A monolithic orthopedic implant made entirely of a brittle, non-resorbable, monolithic material and having an overall implant variability of strength measured as an overall implant Weibull Modulus, the implant comprising:

a porous region having a first variability of strength measured as a first Weibull Modulus;

a transition region located over and integrally joined to the porous region and having a second variability of strength measured as a second Weibull Modulus, wherein the second variability of strength is less than the first variability of strength, and wherein the second Weibull Modulus is greater than the first Weibull Modulus;

a dense region located over and integrally joined to the transition region and having a third variability of strength measured as a third Weibull Modulus, wherein the third variability of strength is less than the second variability of strength, and wherein the third Weibull Modulus is greater than the second Weibull Modulus; and

a surface on top of the dense region, the surface having a finish adapted for articulation against native articular cartilage;

wherein the overall implant variability of strength is less than the third variability of strength, and wherein the overall implant Weibull Modulus is greater than the third Weibull Modulus.

2. The monolithic orthopedic implant of claim 1 wherein the porous region has a bulk porosity of at least 50 percent, wherein the dense region has a bulk porosity of 4 percent or less, and wherein the transition region has a bulk porosity that is between the bulk porosities of the porous and dense regions.

3. The monolithic orthopedic implant of claim 1, wherein the brittle, non-resorbable, monolithic material is selected from the group consisting of oxides, nitrides, carbides, borides, partially stabilized zirconia, alumina, silica, silicon nitride, SiAlON, and pyrolytic carbon.

4. The monolithic orthopedic implant of claim 1, wherein the porous region has a porosity gradient that increases as a distance from the dense region increases.

5. The monolithic orthopedic implant of claim 1, wherein the porous region, the transition region, the dense region, and the surface have a Vickers hardness of 500 MPa or greater, a nickel content of less than 4%, and a chrome content of less than 10%.

6. The monolithic orthopedic implant of claim 1, wherein the dense region has a Vickers hardness of 1000 MPa or greater and a bulk porosity of 4% or less.

7. The monolithic orthopedic implant of claim 1, wherein the surface is finished to a roughness of 6 micrometers R_a or less.

8. The monolithic orthopedic implant of claim 1, wherein the surface is finished to a roughness of 0.025 micrometers R_a or less.

9. The monolithic orthopedic implant of claim 1, wherein the porous region comprises a three dimensional framework of structural members with interstitial interconnected passages therebetween.

10. The monolithic orthopedic implant of claim 1, wherein the porous region has interconnected pore passageways, each having a diameter less than 1000 micrometers.

11. The monolithic orthopedic implant of claim 1, wherein the porous region has interconnected pore passageways each, having a diameter between 200 and 600 micrometers.

12. The monolithic orthopedic implant of claim 1 wherein the porous region has a bulk porosity of 50% or greater.

13. The monolithic orthopedic implant of claim 1 wherein the transition region has a relatively lower porosity than the porous region to provide strength and to support capillary movement of fluid between cancellous bone and articular cartilage.

14. The monolithic orthopedic implant of claim 1, wherein a perimeter of the dense region comprises a roughness of 6 micrometers R_a or greater.

15. The monolithic orthopedic implant of claim 1, wherein the porous region comprises roughness characterized by a frictional coefficient greater than 0.5.

16. The monolithic orthopedic implant of claim 1 wherein the porous region comprises a hydrophilic surface.

17. The monolithic orthopedic implant of claim 1 wherein the porous region comprises a charged surface.

18. The monolithic orthopedic implant of claim 1 wherein the porous region comprises a bioactive mineral coating to promote bone ingrowth for bone fixation.

19. The monolithic orthopedic implant of claim 18, wherein the bioactive mineral coating is selected from the group consisting of hydroxyapatite, bioglass, calcium phosphate, and any combination thereof.

20. The monolithic orthopedic implant of claim 1 wherein the porous region comprises a bioengineered coating to promote bone ingrowth for bone fixation.

21. The monolithic orthopedic implant of claim 20, wherein the bioengineered coating is selected from the group consisting of a protein, a peptide, and any combination thereof.

22. The monolithic orthopedic implant of claim 1, wherein the dense region has a first thickness matching a second thickness of surrounding native articular cartilage.