MONOLITHIC ORTHOPEDIC IMPLANT WITH AN ARTICULAR FINISHED SURFACE

• US 20100268337A1
• Filed: 07/01/2010
• Published: 10/21/2010
• Est. Priority Date: 04/02/2009
• Status: Active Grant

• Current Assignee: Catharon Products Intellectual Property, LLC (Fred DuFresne)
• Original Assignee: Synvasive Technology Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: GORDON, Jeffrey D., JOHNSON, Paul R., JOHANNABER, Kenneth D., FISHER, Michael G.
• Granted Patent: US 8,556,972 B2
• Time in Patent Office: Days
• US Class Current: 623/16.110
• 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
• 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 material comprising:

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.

2. The monolithic material of claim 1 wherein:

the first region and the second region are formed of brittle materials.

3. The monolithic material of claim 1 wherein the first region and the second region comprise:

materials chosen from the group consisting of oxides, nitrides, carbides or borides or any combination thereof;

materials chosen from the group consisting of partially stabilized zirconia, alumina, silica, silicon nitride or SiAlON or any combination thereof;

or

pyrolytic carbon;

or any combination thereof.

4. The monolithic material of claim 1 wherein:

the first region is porous; and

the second region is relatively substantially dense.

5. The monolithic material of claim 1 wherein:

the first region has a first Weibull modulus;

the second region has a second Weibull modulus; and

wherein a Weibull modulus of the monolithic material is less than the first and the second Weibull modulus.

6. The monolithic material of claim 1 wherein:

the first region is porous; and

the second region is relatively substantially dense; and

the monolithic material comprises a third region between and joined to the first region and the second region, the third region having a third variability of strength and a porosity that is relatively lower than a porosity of the first region;

wherein the variability of strength of the monolithic material is less than the third variability of strength of the third region.

7. The monolithic material of claim 6 wherein:

the first region, the second region, and the third region are formed of brittle materials.

8. The monolithic material of claim 6 wherein the first region, the second region, and the third region comprise:

materials chosen from the group consisting of oxides, nitrides, carbides or borides or any combination thereof;

materials chosen from the group consisting of partially stabilized zirconia, alumina, silica, silicon nitride or SiAlON or any combination thereof;

or

pyrolytic carbon;

or

any combination thereof.

9. The monolithic material of claim 6 wherein:

the first region has a first Weibull modulus;

the second region has a second Weibull modulus;

the third region has a third Weibull modulus; and

wherein a Weibull modulus of the monolithic material is less than the first, second, and third Weibull modulus.

10. The monolithic material of claim 6 further comprising:

a surface on the second region, the surface having a finish adapted for articulation against native articular cartilage.

11. A monolithic orthopedic implant comprising:

a porous region having a first variability of strength;

a transition region integrally joined to the porous region and having a second variability of strength;

a substantially dense region integrally joined to the transition region and having a third variability of strength; and

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

wherein the variability of strength of the monolithic orthopedic implant is less than the first, second, and third variability of strengths.

12. The monolithic orthopedic implant of claim 11 wherein

the porous region has a form of interconnected porosity similar to cancellous bone to promote skeletal fixation by bone ingrowth;

and

the transition region has a form of interconnected porosity similar to subchondral bone.

13. The monolithic material of claim 11 wherein:

the porous region, the transition region, and the substantially dense region are formed of brittle materials.

14. The monolithic material of claim 11 wherein the porous region, the transition region, and the substantially dense region comprise:

materials chosen from the group consisting of oxides, nitrides, carbides or borides or any combination thereof;

materials chosen from the group consisting of partially stabilized zirconia, alumina, silica, silicon nitride or SiAlON or any combination thereof;

or

pyrolytic carbon;

or

any combination thereof.

15. The monolithic material of claim 11 wherein:

the porous region has a first Weibull modulus;

the transition region has a second Weibull modulus;

the substantially dense region has a third Weibull modulus; and

wherein a Weibull modulus of the monolithic material is less than the first, second, and third Weibull modulus.

16. The monolithic orthopedic implant of claim 11 wherein the porous region has a porosity gradient that increases as a distance from the substantially dense region increases.

17. The monolithic orthopedic implant of claim 11 wherein the porous region, the transition region, the substantially dense region, and the surface are non-resorbable.

18. The monolithic orthopedic implant of claim 11 wherein the porous region, the transition region, the substantially 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%.

19. The monolithic orthopedic implant of claim 11 wherein the substantially dense region is formed of a material having a Vickers hardness of 1000 MPa or greater and having a bulk porosity of 4% or less, or a material having a Vickers hardness of 1200 MPa or greater and having a bulk porosity of 0.1% or less.

20. The monolithic orthopedic implant of claim 11 wherein the surface is finished to a roughness of 6 micrometers R_a or less.

21. The monolithic orthopedic implant of claim 11 wherein the surface is finished to a roughness of 0.025 micrometers R_a or less.

22. The monolithic orthopedic implant of claim 11 wherein the porous region comprises a three dimensional framework of structural members with interstitial interconnected passages there between.

23. The monolithic orthopedic implant of claim 11 wherein the porous region has interconnected pore passageways each having a dimension less than 1000 micrometers.

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

25. The monolithic orthopedic implant of claim 11 wherein the porous region has a bulk porosity of 50% or greater.

26. The monolithic orthopedic implant of claim 11 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.

27. The monolithic orthopedic implant of claim 11 wherein the monolithic orthopedic implant is adapted for a femoral knee prosthesis, a tibial knee prosthesis, a patellar knee prosthesis, a femoral head hip prosthesis, an acetabular hip prosthesis, a finger or thumb prosthesis, a wrist or ankle prosthesis, a shoulder prosthesis, a toe prosthesis, a spine prosthesis, or an elbow prosthesis.

28. The monolithic orthopedic implant of claim 11 wherein the transition region surrounds a portion of the perimeter of the substantially dense region.

29. The monolithic orthopedic implant of claim 11 wherein the substantially dense region comprises at least one protrusion or at least one indentation.

30. The monolithic orthopedic implant of claim 11 wherein the perimeter of the substantially dense region comprises at least one protrusion or at least one indentation.

31. The monolithic orthopedic implant of claim 11 wherein the porous region has a cylindrical plug shape.

32. The monolithic orthopedic implant of claim 11 wherein the porous region has a tapered plug shape.

33. The monolithic orthopedic implant of claim 11 wherein the porous region has an opening on the bottom and a hollow interior.

34. The monolithic orthopedic implant of claim 11 wherein the perimeter of the substantially dense region comprises roughness to promote healing of articular cartilage.

35. The monolithic orthopedic implant of claim 34 wherein the roughness is 6 micrometers Ra or less.

36. The monolithic orthopedic implant of claim 34 wherein the roughness is greater than 6 micrometers Ra.

37. The monolithic orthopedic implant of claim 11 wherein the perimeter comprises a hydrophilic surface.

38. The monolithic orthopedic implant of claim 11 wherein the perimeter comprises a charged surface.

39. The monolithic orthopedic implant of claim 11 wherein the perimeter comprises a bioactive mineral coating to promote healing of articular cartilage.

40. The monolithic orthopedic implant of claim 39 wherein the bioactive mineral coating comprises hydroxyapatite, bioglass, or a form of calcium phosphate, or any combination thereof.

41. The monolithic orthopedic implant of claim 11 wherein the perimeter comprises a bioengineered coating consisting of a blood derived product, fibrin glue, fibrin clot, protein, a peptide, collagen, impregnated autologous chondrocytes, a pharmaceutical agent, or any combination thereof.

42. The monolithic orthopedic implant of claim 11 wherein a top surface of the porous region is larger than the substantially dense region so that the top surface of the porous region extends beyond the substantially dense region.

43. The monolithic orthopedic implant of claim 11 wherein a top surface of the porous region is smaller than the substantially dense region so that the substantially dense region overhangs the porous region.

44. The monolithic orthopedic implant of claim 11 wherein the perimeter of the substantially dense region has a polygonal shape.

45. The monolithic orthopedic implant of claim 44 wherein the polygonal shape is a triangle, a rectangle, a pentagon, or a hexagon.

46. The monolithic orthopedic implant of claim 11 wherein the perimeter of the substantially dense region is beveled.

47. The monolithic orthopedic implant of claim 46 wherein the substantially dense region has relatively the same dimensions, larger dimensions, or smaller dimensions than a top surface of the porous region.

48. The monolithic orthopedic implant of claim 11 wherein the perimeter of the substantially dense region is reverse beveled.

49. The monolithic orthopedic implant of claim 48 wherein the substantially dense region has relatively the same dimensions, larger dimensions, or smaller dimensions than a top surface of the porous region.

50. The monolithic orthopedic implant of claim 11 wherein the surface has a relative concave spherical shape.

51. The monolithic orthopedic implant of claim 11 wherein the surface has a relative concave shape having a radius in one plane.

52. The monolithic orthopedic implant of claim 11 wherein the surface has a relative concave shape having two differing radii in two orthogonal planes.

53. The monolithic orthopedic implant of claim 11 wherein the surface has a concave shape in one plane and a convex shape in an orthogonal plane.

54. The monolithic orthopedic implant of claim 11 wherein the surface has a convex spherical shape.

55. The monolithic orthopedic implant of claim 11 wherein the surface has a convex shape having a radius in one plane.

56. The monolithic orthopedic implant of claim 11 wherein the surface has a convex shape having two differing radii in two orthogonal planes.

57. The monolithic orthopedic implant of claim 11 wherein the porous region comprises roughness to promote bone ingrowth for bone fixation.

58. The monolithic orthopedic implant of claim 57 wherein the roughness is characterized by a frictional coefficient greater than 0.5.

59. The monolithic orthopedic implant of claim 11:

wherein the porous region comprises a three dimensional framework of structural members with interstitial interconnected passages there between;

wherein each structural member is similar in size to a trabecula in bone; and

wherein each structural member has a surface roughness.

60. The monolithic orthopedic implant of claim 11 wherein the porous region comprises a hydrophilic surface.

61. The monolithic orthopedic implant of claim 11 wherein the porous region comprises a charged surface.

62. The monolithic orthopedic implant of claim 11 wherein the porous region comprises a bioactive mineral coating to promote bone ingrowth for bone fixation.

63. The monolithic orthopedic implant of claim 62 wherein the bioactive mineral coating comprises hydroxyapatite, bioglass, or a form of calcium phosphate or any combination thereof.

64. The monolithic orthopedic implant of claim 11 wherein the porous region comprises a bioengineered coating to promote bone ingrowth for bone fixation.

65. The monolithic orthopedic implant of claim 64 wherein the bioengineered coating consists of a protein or a peptide, or any combination thereof.

66. The monolithic orthopedic implant of claim 11 wherein the substantially dense region has a first thickness matching a second thickness of surrounding native articular cartilage.

67. The monolithic orthopedic implant of claim 11 wherein the porous region comprises a plurality of projections.

68. The monolithic orthopedic implant of claim 11 wherein the monolithic orthopedic implant has a shape having different dimensions in orthogonal planes for a regional implant.

69. The monolithic orthopedic implant of claim 68 wherein the porous region has a tapered perimeter.

70. The monolithic orthopedic implant of claim 11 wherein:

the substantially dense region has a shell like shape; and

the porous region has a shell-like shape having a hollow interior.

71. A method of providing a monolithic material comprising:

forming a porous region having a first variability of strength; and

forming a substantially dense region joined to the porous region and having a second variability of strength;

wherein the variability of strength of the monolithic material is less than the first and second variability of strengths.

72. The method of claim 71 further comprising:

forming a transition region between the porous region and the substantially dense region and joined to the porous region and the substantially dense region, the transition region having a third variability of strength;

wherein the variability of strength of the monolithic material is less than the third variability of strength.

73. The method of claim 72 further comprising:

forming a surface on the substantially dense region, the surface having a finish adapted for articulation against native articular cartilage.

74. The method of claim 72 wherein:

the porous region has a form of interconnected porosity similar to cancellous bone to promote skeletal fixation by bone ingrowth; and

the transition region has a form of interconnected porosity similar to subchondral bone.

75. The method of claim 72 wherein:

wherein the porous region has a porosity gradient that increases as a distance from the substantially dense region increases.

76. The method of claim 72 wherein:

the porous region, the transition region, and the substantially dense region are formed of brittle materials.

77. The method of claim 72 wherein the porous region, the transition region, and the substantially dense region comprise:

materials chosen from the group consisting of oxides, nitrides, carbides or borides or any combination thereof;

materials chosen from the group consisting of partially stabilized zirconia, alumina, silica, silicon nitride or SiAlON or any combination thereof;

or

pyrolytic carbon;

or

any combination thereof.

78. The method of claim 72 wherein:

the porous region has a first Weibull modulus;

the transition region has a second Weibull modulus;

the substantially dense region has a third Weibull modulus; and

wherein a Weibull modulus of the monolithic material is less than the first, second, and third Weibull modulus.

79. The method of claim 72 wherein:

wherein the porous region, the transition region and the substantially dense region are non-resorbable.

80. The method of claim 73 wherein forming the surface on the substantially dense region comprises thermal processing the substantially dense region.

81. The method of claim 73 wherein forming the surface on the substantially dense region comprises depositing a material on the substantially dense region.

82. The method of claim 81 wherein the deposited material is pyrolytic carbon, or diamond-like carbon.

83. The method of claim 73 wherein forming the surface on the substantially dense region comprises coating a material on the substantially dense region.

84. The method of claim 83 wherein the coated material is ceramic or ceramic like.

85. The method of claim 73 wherein forming the surface on the substantially dense region comprises forming at least one protrusion or at least one indentation on the substantially dense region.

86. The method of claim 72 wherein forming the substantially dense region comprises forming at least one protrusion or at least one indentation on the substantially dense region.

87. The method of claim 72 wherein forming the porous region or forming the transition region comprises oxidizing a fugitive material.

88. The method of claim 72 wherein forming the porous region or forming the transition region comprises dissolving a fugitive material.

89. The method of claim 72 wherein forming the porous region or forming the transition region comprises using a lost foam process.

90. The method of claim 72 wherein forming the porous region or forming the transition region comprises using a solid freeform fabrication process.

91. The method of claim 72 wherein forming the porous region or forming the transition region comprises using a foaming process.

92. The method of claim 72 further comprising fabricating a desired geometrical form for the porous region, the transition region and the substantially dense region by milling, turning, grinding or other machining processes.

93. The method of claim 92 wherein fabricating a desired geometrical form further comprises accounting for shrinkage of 10% or greater following milling, turning, grinding or other machining processes.

94. The method of claim 92 wherein fabricating a desired geometrical form comprises fabricating a femoral knee prosthesis, a tibial knee prosthesis, a patellar knee prosthesis, a femoral head hip prosthesis, an acetabular hip prosthesis, a finger or thumb prosthesis, a wrist or ankle prosthesis, a shoulder prosthesis, a toe prosthesis, a spine prosthesis, or an elbow prosthesis.

95. The method of claim 72 wherein the porous region, the transition region and the substantially dense region have a Vickers hardness of 500 MPa or greater, a nickel content of less than 4%, and a chrome content of less than 10%.

96. A method of providing a monolithic material comprising:

forming a first region having a first variability of strength; and

forming 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.

97. The method of claim 96 further comprising:

forming a third region between and joined to the first region and the second region, the third region having a third variability of strength;

wherein the variability of strength of the monolithic material is less than the third variability of strength of the third region.

98. The method of claim 97 wherein the first, second and third regions comprise:

materials chosen from the group consisting of oxides, nitrides, carbides or borides or any combination thereof;

materials chosen from the group consisting of partially stabilized zirconia, alumina, silica, silicon nitride or SiAlON or any combination thereof;

or

pyrolytic carbon;

or any combination thereof.

99. The method of claim 97 wherein:

the first region has a first Weibull modulus;

the second region has a second Weibull modulus; and

the third region has a third Weibull modulus;

wherein a Weibull modulus of the monolithic material is less than the first, second and third Weibull modulus.