Relating to joints and/or implants

• US 9,370,426 B2
• Filed: 09/08/2008
• Issued: 06/21/2016
• Est. Priority Date: 05/28/2008
• Status: Active Grant

• Current Assignee: Renishaw PLC
• Original Assignee: Renishaw PLC
• Inventors: Gabbrielli, Ruggero, Turner, Irene Gladys, Bowen, Christopher Rhys, Magalini, Emanuele
• Primary Examiner(s): STEWART, ALVIN J
• Application Number:
  US12/994,666
• Publication Number:
  US 20110125284A1
• Time in Patent Office: 2,843 Days
• Field of Search: 623 2221- 2239, 623/23.29, 623 2353- 2355, 623 2372- 2376
• US Class Current: 1/1
• 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 2/32 for the hip
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3662 Femoral shafts
• CPC Class Codes: A61F 2/367 Proximal or metaphyseal parts of shafts trochanteric devices connected to said proximal parts A61F2/30739
• CPC Class Codes: A61F 2/3672 Intermediate parts of shafts
• CPC Class Codes: A61F 2/3676 Distal or diaphyseal parts of shafts
• 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 2002/30322 differing in surface structures
• CPC Class Codes: A61F 2002/30838 Microstructures
• 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 2002/3611 Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2210/0004 bioabsorbable
• CPC Class Codes: A61F 2250/0023 differing in porosity
• CPC Class Codes: A61F 2250/0026 differing in surface structures
• CPC Class Codes: A61F 2310/00011 Metals or alloys
• 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 2310/00179 : Ceramics or ceramic-like structures
• CPC Class Codes: A61F 2310/00203 : containing alumina or aluminium oxide
• CPC Class Codes: A61F 2310/00239 : containing zirconia or zirconium oxide ZrO2
• CPC Class Codes: A61F 2310/00293 : containing a phosphorus-containing compound, e.g. apatite
• CPC Class Codes: A61F 2310/00329 : Glasses, e.g. bioglass
• CPC Class Codes: B22F 7/004 : comprising at least one non-porous part
• CPC Class Codes: Y10T 29/4978 : Assisting assembly or disassembly

Abstract

A joint part (1) has a porous portion (2) that is defined by a multiplicity of solid regions where material is present and a remaining multiplicity of pore regions where material is absent, the locations of at least most of the multiplicity of solid regions being defined by one or more mathematical functions. The nature of the porous portion can be varied systematically by changing one or more constants in the mathematical functions and the part is made by a process of solid freeform fabrication.

Claims

1. A joint part comprising a porous portion, the porous portion having:

a multiplicity of solid regions where material is present, locations of at least most of the multiplicity of solid regions being defined by one or more mathematical functions; and

a remaining multiplicity of pore regions where material is absent,

wherein the one or more mathematical functions define the solid region locations so that the locations of the remaining multiplicity of pore regions are nonrandom, and

wherein the one or more mathematical functions include at least one term that defines a porosity gradient such that porosity of at least part of the porous portion changes continuously and without any discontinuity.

2. A joint part according to claim 1, in which the locations of all the solid regions of the joint part are defined mathematically.

3. A joint part according to claim 1, in which the one or more mathematical functions define a periodic nodal surface as a boundary surface between the solid and the pore regions.

4. A joint part according to claim 3, in which the periodic nodal surface is selected from the group comprising a primitive (P) surface, a diamond (D) surface and a gyroid (G) surface, the primitive (P) surface, the diamond (D) surface, and the gyroid (G) surface having interconnectivity orders equal to 6, 4, and 3, respectively.

5. A joint part according to claim 4, in which the periodic nodal surface is selected from the group consisting of the primitive (P) surface, the diamond (D) surface, and the gyroid (G) surface.

6. A joint part according to claim 1, in which the joint part further includes a solid portion, the porous portion and the solid portion being part of the same single piece.

7. A joint part accordingly to claim 6, in which the porosity of the porous portion in the region bordering the solid portion is substantially equal to the porosity of the solid portion, the porosity of the porous portion increasing away from the solid portion.

8. A joint part according to claim 1, in which the joint part is a ball and socket joint.

9. A joint part according to claim 8, in which the porous portion defines a socket of the ball and socket joint.

10. A joint part according to claim 9, in which the socket has a concave load-bearing cup portion which is solid and the porous portion extends outwardly from the cup portion to a peripheral outer surface.

11. A joint part according to claim 8, in which the porous portion defines a ball of the ball and socket joint.

12. A joint part according to claim 11, in which the ball has a convex load-bearing ball portion which is solid and the porous portion extends away from the ball portion.

13. A joint part according to claim 1, in which the joint part is a load-bearing implant suitable for implanting in a human body.

14. A joint part according to claim 1, in which the one or more mathematical functions define the distance between adjacent solid regions of the multiplicity of solid regions.

15. A joint part according to claim 1, in which each of the solid regions in the multiplicity of solid regions has the same contour as the other solid regions.

16. A joint part according to claim 1, in which the at least one term comprises a linear term.

17. A joint part according to claim 1, in which the at least one term comprises a radial term.

18. A load-bearing implant comprising a porous portion, the porous portion having:

a multiplicity of solid regions where material is present, locations of at least most of the multiplicity of solid regions being defined by one or more mathematical functions; and

a remaining multiplicity of pore regions where material is absent,

wherein the one or more mathematical functions define the solid region locations so that the locations of the remaining multiplicity of pore regions are nonrandom, and

wherein the one or more mathematical functions include at least one term that defines a porosity gradient such that porosity of at least part of the porous portion changes continuously and without any discontinuity.

19. A load-bearing implant according to claim 18, in which the locations of all the solid regions of the implant are defined mathematically.

20. A load-bearing implant according to claim 18, in which the one or more mathematical functions define a periodic nodal surface as a boundary surface between the solid and the pore regions.

21. A load-bearing implant according to claim 20, in which the periodic nodal surface is selected from the group comprising a primitive (P) surface, a diamond (D) surface and a gyroid (G) surface, the primitive (P) surface, the diamond (D) surface, and the gyroid (G) surface having interconnectivity orders equal to 6, 4, and 3, respectively.

22. A load-bearing implant according to claim 18, in which the implant is made of metal.

23. A load-bearing implant according to claim 18, in which the implant is made of ceramic material.

24. A load-bearing implant according to claim 18, in which the implant is made of polymeric material.

25. A load-bearing implant according to claim 18, in which the implant further includes a solid portion, the porous portion and the solid portion being part of the same single piece.

26. A load-bearing implant according to claim 25, in which the porosity of the porous portion in the region bordering the solid portion is substantially equal to the porosity of the solid portion, the porosity of the porous portion increasing away from the solid portion.

27. A load-bearing implant according to claim 25, in which the solid portion defines a cup which provides part or all of the socket of a ball and socket joint.

28. A load-bearing implant according to claim 27, in which the cup has a concave load bearing cup portion which is solid and the porous portion extends outwardly from the cup portion to a peripheral outer surface.

29. A load-bearing implant according to claim 27, in which the cup is an acetabular cup.

30. A load-bearing implant according to claim 25, in which the solid portion defines a ball which provides part or all of the ball of a ball and socket joint.

31. A load-bearing implant according to claim 30, in which the ball has a convex load bearing ball portion which is solid and the porous portion extends away from the ball portion.