Reinforced medical implants

• US 20080208353A1
• Filed: 02/28/2007
• Published: 08/28/2008
• Est. Priority Date: 02/28/2007
• Status: Active Grant

• Current Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Biomet Manufacturing, LLC (Zimmer Biomet Holdings, Inc.)
• Inventors: Fleming, James B., Kumar, Mukesh
• Granted Patent: US 8,043,382 B2
• Time in Patent Office: Days
• US Class Current: 623/23.56
• 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 17/70 Spinal positioners or stabilisers ; Bone stabilisers comprising fluid filler in an implant
• CPC Class Codes: A61B 17/80 Cortical plates , i.e. bone plates; Instruments for holding or positioning cortical plates, or for compressing bones attached to cortical plates
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/30942 for designing or making customized prostheses, e.g. using templates, CT or NMR scans, finite-element analysis or CAD-CAM techniques
• CPC Class Codes: A61F 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/3601 for replacing only the epiphyseal or metaphyseal parts of the femur, e.g. endoprosthetic femoral heads or necks directly fixed to the natural femur by internal fixation devices non-prosthetic internal fixation devices for the femoral head or neck A61B17/74
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/4003 Replacing only the epiphyseal or metaphyseal parts of the humerus, i.e. endoprosthesis not comprising an entire humeral shaft replacing only the epiphyseal or metaphyseal parts of the femur A61F2/3601
• CPC Class Codes: A61F 2/44 for the spine, e.g. vertebrae, spinal discs
• CPC Class Codes: A61F 2002/2817 Bone stimulation by chemical reactions or by osteogenic or biological products for enhancing ossification, e.g. by bone morphogenetic or morphogenic proteins [BMP] or by transforming growth factors [TGF]
• CPC Class Codes: A61F 2002/30113 circular
• CPC Class Codes: A61F 2002/30154 square
• CPC Class Codes: A61F 2002/30156 triangular
• CPC Class Codes: A61F 2002/30166 H-shaped or I-shaped
• CPC Class Codes: A61F 2002/30289 helically-coiled
• CPC Class Codes: A61F 2002/30291 spirally-coiled, i.e. having a 2D spiral cross-section
• CPC Class Codes: A61F 2002/30303 polypod-shaped
• CPC Class Codes: A61F 2002/30841 : Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• 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 2002/30892 : parallel
• CPC Class Codes: A61F 2002/30909 : Nets
• CPC Class Codes: A61F 2002/30957 : using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30968 : Sintering
• CPC Class Codes: A61F 2002/4007 : implanted without ablation of the whole natural humeral head
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0021 : square
• CPC Class Codes: A61F 2230/0023 : triangular
• CPC Class Codes: A61F 2230/0028 : Shapes in the form of latin or greek characters
• CPC Class Codes: A61F 2230/0063 : Three-dimensional shapes
• CPC Class Codes: A61F 2230/0091 : helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section
• CPC Class Codes: A61F 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00185 : based on metal oxides
• CPC Class Codes: A61F 2310/00203 : containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00227 : containing titania or titanium oxide
• CPC Class Codes: A61F 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00263 : based on metal borides
• CPC Class Codes: A61F 2310/00269 : based on metal carbides
• CPC Class Codes: A61F 2310/00281 : containing silicon carbide
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00299 : based on metal nitrides
• CPC Class Codes: A61F 2310/00395 : Coating or prosthesis-covering structure made of metals or of alloys
• CPC Class Codes: A61L 27/30 : Inorganic materials
• CPC Class Codes: A61L 27/42 : having an inorganic matrix
• CPC Class Codes: A61L 27/427 : of other specific inorganic materials not covered by A61L27/422 or A61L27/425

Abstract

Medical implants having a ceramic body reinforced with a plurality of metal wires. Methods of making the implant and methods of implanting the medical implant are also provided.

Claims

1. A medical implant, comprising:

a ceramic body having a shape operable for use in the implant; and

a plurality of solid metal wires embedded in the ceramic body.

2. A medical implant of claim 1, wherein a plurality of the metal wires extends outside a first surface of the ceramic body.

3. A medical implant according to claim 2, comprising a second surface operable as an articulating surface for the implant.

4. A medical implant according to claim 2, wherein the first surface is coated with a metallic layer.

5. A medical implant according to claim 1, wherein the ceramic body is made of a material selected from the group consisting of titanium oxide, titanium dioxide, alumina ceramics, zirconia ceramics, silicon carbide, stabilized zirconia, and mixtures thereof.

6. A medical implant according to claim 1, wherein the metal wire is non-reactive with the ceramic body.

7. A medical implant according to claim 1, wherein the metal wire comprises a metal selected from the group consisting of cobalt-chrome-molybdenum, cobalt, molybdenum, titanium, tantalum, tungsten, gold, platinum, alloys thereof, and combinations thereof.

8. A medical implant according to claim 7, wherein the metal wire comprises titanium, tungsten, or combinations thereof.

9. A medical implant according to claim 1, wherein the metal wires comprise a form selected from the group consisting of meshes, fibrous webs, coils, and combinations thereof.

10. A medical implant according to claim 9, wherein the form is a mesh.

11. A medical implant according to claim 1, wherein the wires further comprise a surface feature.

12. A medical implant according to claim 1, having compressive stress lines at an interface between a perimeter of the metal wire and an area of the ceramic body adjacent to the metal wire.

13. A medical implant according to claim 1, further comprising an attachment feature operable for attaching the medical implant to an implant site.

14. A medical implant according to claim 13, wherein the attachment feature is a post.

15. A medical implant according to claim 13, wherein the metal wire is placed proximate to the attachment feature so as to reinforce the implant in the area of the feature.

16. A medical implant according to claim 1, wherein the medical implant is selected from the group consisting of:

an acetabular cup, a shoulder implant, and a knee implant.

17. A method for forming a medical implant, comprising:

placing a plurality of metal wires in a mold;

covering at least a region of the metal wires with a ceramic material; and

compacting the metal wire reinforcement and the ceramic in the mold to form a green body.

18. A method for forming a medical implant according to claim 17, wherein the compacting is performed using a cold isostatic press.

19. A method of claim 17, wherein the ceramic material is in a form selected from the group consisting of:

a fluid, a dry powder, and combinations thereof.

20. A method of claim 17, wherein the ceramic material further comprises an agent selected from the group consisting of binders, deflocculating agents, and combinations thereof.

21. A method of claim 17, further comprising completely covering the metal wire reinforcement with the ceramic material.

22. A method of claim 17, further comprising sintering the green body.

23. A method of claim 22 wherein the sintering temperature is less than the melting temperature of the metal wire.

24. A method of claim 22 wherein the sintering temperature is equal to or greater than the melting temperature of the metal wire.

25. A method of claim 24, wherein the sintering temperature is sufficient to deform the metal wire reinforcement.

26. A method of claim 22, wherein the sintering temperature is sufficient to cause expansion of the metal wire.

27. A method of claim 26, wherein a thermal mismatch between the metal wire and the ceramic material increases the compressive strength of the medical implant.

28. The method of claim 18, further comprising machining the green body.

29. A method for forming a medical implant having a plurality of solid metal wires embedded therein, comprising:

forming a green body comprising a plurality of polymer wires, at least a portion of which is covered with a ceramic material;

heating the green body so as to remove the plurality of polymer wires and form a ceramic body having a plurality of channels;

filling the plurality of channels with a metal powder; and

sintering the ceramic body to form the solid metal wires from the metal powder.

30. A method according to claim 29, where the ceramic body is made of a material selected from the group consisting of alumina ceramics, zirconia ceramics, silicon carbide, stabilized zirconia, and mixtures thereof.

31. A method according to claim 30, wherein the wires comprise a form selected from the group consisting of meshes, fibrous webs, coils, and combinations thereof.

32. A method according to claim 29, wherein the forming comprises placing a plurality of polymer wires in a mold;

and covering at least a region of the plurality of polymer wires with a ceramic material

33. A method according to claim 29, wherein the heating comprises sintering the green body.

34. A method of securing an articulating medical implant to an implant site, comprising:

providing the articulating medical implant comprising;

a ceramic body having a shape operable for use in the implant; and

a plurality of solid metal wires embedded in the ceramic body;

wherein a first region of the metal wire reinforcement is contained inside of the ceramic body to provide an articulating surface and a second region of metal wire reinforcement extends outside of the ceramic body to provide a porous matrix on a non-articulating side of the implant; and

attaching the non-articulating side of the implant to bone.