Porous metal structures made from polymer preforms

• US 9,226,827 B2
• Filed: 11/16/2011
• Issued: 01/05/2016
• Est. Priority Date: 11/17/2010
• Status: Active Grant

• Current Assignee: Zimmer GmbH (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer GmbH (Zimmer Biomet Holdings, Inc.)
• Inventors: Luscher, Patrik
• Primary Examiner(s): STEWART, JASON-DENNIS NEILKEN
• Application Number:
  US13/885,303
• Publication Number:
  US 20130310948A1
• Time in Patent Office: 1,511 Days
• Field of Search: 623/16.11, 623/18.11, 623 2351- 2361, 427/2.24
• US Class Current: 1/1
• CPC Class Codes: A61B 17/68 Internal fixation devices , including fasteners and spinal fixators, even if a part thereof projects from the skin bone staples A61B17/0642
• CPC Class Codes: A61B 17/866 Material or manufacture
• CPC Class Codes: A61C 13/0003 Making bridge-work, inlays, implants or the like
• CPC Class Codes: A61C 8/0012 characterised by the material or composition, e.g. ceramics, surface layer, metal alloy use of specific materials A61K6/00
• CPC Class Codes: A61C 8/0013 with a surface layer, coating
• CPC Class Codes: A61C 8/0016 polymeric material
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30756 Cartilage endoprostheses A61F2/3603 takes precedence
• CPC Class Codes: A61F 2/30907 Nets or sleeves applied to surface of prostheses or in cement
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2/4241 for hands, e.g. fingers
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30884 Fins or wings, e.g. longitudinal wings for preventing rotation within the bone cavity
• CPC Class Codes: A61F 2002/30899 Protrusions pierced with apertures
• CPC Class Codes: A61F 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30962 using stereolithography
• CPC Class Codes: A61F 2002/30973 Two joined adjacent layers having complementary interlocking protrusions and recesses
• CPC Class Codes: A61F 2002/30985 using three dimensional printing [3DP]
• CPC Class Codes: A61L 27/306 : Other specific inorganic materials not covered by A61L27/303 - A61L27/32
• CPC Class Codes: A61L 27/56 : Porous materials, e.g. foams or sponges
• CPC Class Codes: B33Y 80/00 : Products made by additive manufacturing

Abstract

The present disclosure relates to porous orthopedic implants made from polymer preforms and a method of manufacturing the same. A polymer material may be formed into a preform, such as by an injection molding process or an additive manufacturing process. In an exemplary embodiment, the overall shape and the porous framework of the preform is predetermined to be substantially the same as the overall shape and the porous framework of the final orthopedic implant. Then, the preform may be pyrolyzed and coated with metal to form the final orthopedic implant.

Claims

1. A method of manufacturing a porous orthopedic implant comprising the steps of:

forming a polymeric preform in a three-dimensional geometric shape that is substantially the same as the three-dimensional geometric shape of the orthopedic implant, the polymeric preform including a plurality of ligaments defining pores therebetween;

after said forming the polymeric preform, pyrolyzing the polymeric preform; and

after said pyrolyzing the polymeric preform, coating the pyrolyzed polymeric preform with metal to produce the orthopedic implant.

2. The method of claim 1, wherein the preform produced during the forming step and the orthopedic implant produced during the coating step differ in scale.

3. The method of claim 2, wherein the preform produced during the forming step is larger in scale than the orthopedic implant produced during the coating step to account for shrinkage of the plurality of ligaments during the pyrolyzing step.

4. The method of claim 1, wherein the forming step comprises injecting one of a polymer material and an unpolymerized material into a mold to form the preform,

and/or wherein the forming step comprises performing a rapid manufacturing process to form the preform,

and/or wherein the forming step comprises depositing a polymer material layer by layer to form the preform,

and/or wherein the forming step comprises cutting the preform out of a starting material to form the preform.

5. The method of claim 1, wherein the forming step comprises separately forming a first portion of the preform and a second portion of the preform, the method further comprising the step of coupling the first and second portions of the preform together.

6. The method of claim 1, further comprising the step of providing an unformed polymer material before the forming step, wherein the forming step occurs without further polymerization of the polymer material,

in particular wherein the unformed polymer material is in one of a powdered state and a molten state.

7. A porous orthopedic implant obtained by the method of claim 1.

8. The implant according to claim 7, wherein the method is carried out such that the ligaments exhibit a spatial structure being different from a random spatial structure, in particular wherein the spatial structure of the ligaments is such that the implant has at least one of (i) an anisotropic and/or locally varying structure, (ii) anisotropic and/or locally varying mechanical properties, (iii) an anisotropic and/or locally varying porosity, and (iv) mechanical properties being dependent on the direction of an externally applied load.

9. A method of manufacturing a porous orthopedic implant comprising the steps of:

forming a polymeric preform having a substantially final shape that is suitable for implantation into a patient'"'"'s body, the polymeric preform including a plurality of ligaments defining pores therebetween;

after said forming the polymeric preform, pyrolyzing the polymeric preform; and

after said pyrolyzing the polymeric preform, coating the pyrolyzed polymeric preform with metal to produce the orthopedic implant.

10. The method of claim 9, wherein the pyrolyzing step and the coating step alter the scale of the preform while substantially maintaining the final shape of the preform.

11. The method of claim 9, wherein the step of forming the preform does not include a machining.

12. The method of claim 9, wherein the forming step comprises forming each of the plurality of ligaments at a predetermined location, in a predetermined size, and in a predetermined shape.

13. The method of claim 9, further comprising the step of attaching a polymeric bearing layer to the orthopedic implant after the coating step.

14. A method of manufacturing a porous orthopedic implant comprising the steps of:

forming a plurality of polymeric ligaments, each ligament having a predetermined location, a predetermined size, and a predetermined shape, the plurality of ligaments defining pores therebetween, the plurality of ligaments cooperating to define at least a portion of a preform;

after said forming the plurality of polymeric ligaments, pyrolyzing the preform; and

after said pyrolyzing the preform, coating the pyrolyzed preform with metal to produce the orthopedic implant.

15. The method of claim 14, wherein the forming step comprises performing at least one of stereolithography, selective laser sintering, and fused deposition modeling.