Method for forming porous metal implants

• US 8,361,380 B2
• Filed: 02/07/2011
• Issued: 01/29/2013
• Est. Priority Date: 02/17/2006
• Status: Expired due to Fees

• Current Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Inventors: Hamman, Ned M., Fleming, James B., Janson, Isaac, Kumar, Mukesh, Meridew, Jason D., Schlueter, Elizabeth A.
• Primary Examiner(s): King, Roy
• Assistant Examiner(s): MAI, NGOCLAN THI
• Application Number:
  US13/021,987
• Publication Number:
  US 20110123382A1
• Time in Patent Office: 722 Days
• Field of Search: 419/2, 419/23, 419 36- 38, 419/42
• US Class Current: 419/2
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/30907 Nets or sleeves applied to surface of prostheses or in cement
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30064 Coating or prosthesis-covering structure made of biodegradable material
• CPC Class Codes: A61F 2002/30166 H-shaped or I-shaped
• CPC Class Codes: A61F 2002/30169 Pi-shaped
• CPC Class Codes: A61F 2002/302 toroidal, e.g. rings
• CPC Class Codes: A61F 2002/30205 conical
• CPC Class Codes: A61F 2002/30224 cylindrical
• CPC Class Codes: A61F 2002/30235 tubular, e.g. sleeves
• CPC Class Codes: A61F 2002/30261 parallelepipedal
• CPC Class Codes: A61F 2002/30383 made by laterally inserting a protrusion, e.g. a rib into a complementarily-shaped groove
• CPC Class Codes: A61F 2002/30451 soldered or brazed or welded
• CPC Class Codes: A61F 2002/305 Snap connection
• CPC Class Codes: A61F 2002/30604 modular
• CPC Class Codes: A61F 2002/30736 Augments or augmentation pieces, e.g. wedges or blocks for bridging a bone defect
• CPC Class Codes: A61F 2002/30827 : Plurality of grooves
• 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 2002/30968 : Sintering
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0058 : soldered or brazed or welded
• CPC Class Codes: A61F 2230/0028 : Shapes in the form of latin or greek characters
• CPC Class Codes: A61F 2230/0047 : Pi-shaped
• CPC Class Codes: A61F 2230/0065 : toroidal, e.g. ring-shaped, doughnut-shaped
• CPC Class Codes: A61F 2230/0067 : conical
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2230/0082 : parallelepipedal
• CPC Class Codes: A61F 2250/0023 : differing in porosity
• CPC Class Codes: A61F 2310/00017 : Iron- or Fe-based alloys, e.g. stainless steel
• CPC Class Codes: A61F 2310/00023 : Titanium or titanium-based alloys, e.g. Ti-Ni alloys
• CPC Class Codes: A61F 2310/00029 : Cobalt-based alloys, e.g. Co-Cr alloys or Vitallium
• CPC Class Codes: A61F 2310/00059 : Chromium or Cr-based alloys
• CPC Class Codes: A61F 2310/00131 : Tantalum or Ta-based alloys
• CPC Class Codes: A61F 2310/00592 : Coating or prosthesis-covering structure made of ceramics or of ceramic-like compounds
• CPC Class Codes: A61F 2310/00958 : Coating or prosthesis-covering structure made of bone or of bony tissue
• CPC Class Codes: A61F 2310/0097 : Coating or prosthesis-covering structure made of pharmaceutical products, e.g. antibiotics
• 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: A61K 35/12 : Materials from mammals; Compositions comprising non-specified tissues or cells; Compositions comprising non-embryonic stem cells; Genetically modified cells vaccines or medicinal preparations containing antigens or antibodies A61K39/00
• CPC Class Codes: A61L 2300/25 : Peptides having up to 20 amino acids in a defined sequence
• CPC Class Codes: A61L 2300/406 : Antibiotics
• CPC Class Codes: A61L 2300/414 : Growth factors
• CPC Class Codes: A61L 2300/428 : Vitamins, e.g. tocopherol, riboflavin
• CPC Class Codes: A61L 2300/606 : Coatings
• CPC Class Codes: A61L 2300/64 : Animal cells
• CPC Class Codes: A61L 27/04 : Metals or alloys
• CPC Class Codes: A61L 27/54 : Biologically active materials, e.g. therapeutic substances A61L27/227 takes precedence
• CPC Class Codes: A61L 27/56 : Porous materials, e.g. foams or sponges
• CPC Class Codes: B22F 1/10 : Metallic powder containing lubricating or binding agents; Metallic powder containing organic material
• CPC Class Codes: B22F 1/103 : containing an organic binding agent comprising a mixture of, or obtained by reaction of, two or more components other than a solvent or a lubricating agent
• CPC Class Codes: B22F 2998/10 : Processes characterised by the sequence of their steps
• CPC Class Codes: B22F 3/02 : Compacting only
• CPC Class Codes: B22F 3/04 : by applying fluid pressure , e.g. by cold isostatic pressing [CIP]
• CPC Class Codes: B22F 3/1021 : Removal of binder or filler removal of binder from ceramics C04B35/638
• CPC Class Codes: B22F 3/1125 : involving a foaming process
• CPC Class Codes: B22F 3/1216 : Container composition
• CPC Class Codes: C01P 2004/61 : Micrometer sized, i.e. from 1-100 micrometer
• CPC Class Codes: C09C 1/00 : Treatment of specific inorganic materials other than fibrous fillers tenebrescent materials C09K9/00; luminescent materials C09K11/00; Preparation of carbon black

Abstract

A method for providing a porous metal implant. A mixture of biocompatible metal, a spacing agent, and a binder is provided. The mixture is formed into a shape and the spacing agent is removed to form a plurality of pores in the implant. A shaped porous metal is also provided.

Claims

1. A method for preparing a porous metal implant comprising:

a. preparing a mixture comprising;

i. a biocompatible metal powder comprising a metal selected from the group consisting of titanium, titanium alloys, cobalt, cobalt alloys, chromium, chromium alloys, tantalum, tantalum alloys, and stainless steel;

ii a spacing agent selected from the group consisting of hydrogen peroxide, urea, ammonium carbonate, ammonium bicarbonate, ammonium carbamate, calcium hydrogen phosphate, naphthalene, and mixtures thereof; and

iii. a non-polar liquid binder in which the spacing agent is substantially insoluble;

b. forming the mixture into a shape; and

c. heating the mixture so as to sinter the metal powder into a metal implant having a plurality of pores.

2. The method of claim 1, wherein the biocompatible metal powder comprises a titanium alloy.

3. The method of claim 1, wherein the metal powder has a particle size of from about 5 micrometers to about 1500 micrometers.

4. The method of claim 1, wherein the metal powder comprises a mixture of metal powders of different particulate sizes.

5. The method of claim 1, wherein the plurality of pores comprises pores of different sizes.

6. The method of claim 1, wherein the spacing agent comprises ammonium bicarbonate.

7. The method of claim 1, wherein the spacing agent has a particle size of from about 1 micrometer to about 1500 micrometers.

8. The method of claim 1, wherein the binder comprises d-limonene.

9. The method of claim 6, wherein the binder comprises d-limonene.

10. The method of claim 1, wherein the heating is at a temperature that sublimes the spacing agent.

11. The method of claim 10, wherein the binder and the spacing agent form a cohesive mixture, the binder has a boiling point, the spacing agent has a sublimation or decomposition temperature, and the boiling point and the sublimation or decomposition temperatures are such that the binder and the spacing agent are removed during the heating step.

12. The method of claim 11, wherein the binder is d-limonene and the spacing agent is ammonium bicarbonate.

13. The method of claim 1, wherein the weight ratio of metal powder to spacing agent is from about 1:

1 to about 10;

1.

14. The method of claim 1, wherein the weight ratio of the (i) binder to (ii) solid spacing agent and metal powder is from about 1:

10 to about 1;

30.

15. The method of claim 1, wherein the forming comprises application of isostatic pressure to the mixture.

16. The method of claim 15, wherein the pressure is from 170 megapascals to 500 megapascals.

17. The method of claim 1, wherein the heating comprises

(i) a first sintering;

(ii) quenching; and

(iii) a second sintering.

18. The method of claim 17, wherein the temperature of the second sintering is lower than the temperature of the first sintering.

19. The method of claim 1, further comprising attaching a metal substrate to the metal implant.

20. The method of claim 19, wherein the attaching is by sintering.

21. A method for preparing a porous metal implant comprising:

a. preparing a mixture comprising;

i. a biocompatible metal powder comprising a metal selected from the group consisting of titanium, titanium alloys, cobalt, cobalt alloys, chromium, chromium alloys, tantalum, tantalum alloys, and stainless steel;

ii. ammonium carbonate; and

iii. a non-polar liquid binder in which the spacing agent is substantially insoluble;

b. subjecting the mixture to pressure, so as to form the mixture into a shape; and

c. heating the mixture so as to sinter the metal powder into a metal implant having a plurality of pores, wherein the heating comprises a thermal cycle of sintering at a first temperature, quenching, and sintering at a second temperature lower than the first temperature.

22. The method of claim 21, wherein the biocompatible metal powder is a titanium alloy.

23. The method of claim 22, wherein the metal powder is Ti-6Al-4V.

24. The method of claim 21, wherein the non-polar liquid binder comprises d-limonene.

25. The method of claim 21, wherein the pressure comprises cold isostatic pressure.

26. The method of claim 21, further comprising attaching a metal substrate to the implant by sintering.

27. A method for preparing a porous metal implant comprising:

a. preparing a mixture comprising;

i. a biocompatible metal powder comprising a metal selected from the group consisting of titanium, titanium alloys, cobalt, cobalt alloys, chromium, chromium alloys, tantalum, tantalum alloys, and stainless steel;

ii. ammonium carbonate; and

iii. d-limonene;

b. forming the mixture into a shape by subjecting the mixture to cold isostatic pressure;

c. sintering the mixture at a first temperature of over 1000°

C.;

d. quenching the mixture; and

e. sintering the mixture at a temperature of from about 500°

C. to about 900°

C.

28. The method of claim 27, wherein the biocompatible metal powder is a titanium alloy.

29. The method of claim 27, further comprising attaching a metal substrate to the implant by sintering.