Implantable joint prosthesis
First Claim
1. A surgical implant suitable for use in a joint between the surfaces of two bones, comprising:
- two rigid opposing shells, each having an outer surface adapted to engage the surfaces of the bones of a joint in such a way that movement of the shell relative to the bone surface is resisted by friction between the outer surface and the surface of the bone;
an inner surface that is smoother than the outer surface; and
an edge between the outer surface and the inner surface;
a deformable, resilient central body disposed between the inner surfaces of the shells comprising an outer surface, at least a portion of which has a shape that complements and articulates with the shape of the inner surface of one or both rigid opposing shells to allow the inner surface of the rigid opposing shell and the outer surface of the central body to move easily with respect to each other within a constrained range of motion, but to resist such movement outside the constrained range of motion.
6 Assignments
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Accused Products
Abstract
The invention relates to a surgical implant that provides an artificial diarthroidal-like joint, suitable for use in replacing any joint, but particularly suitable for use as an intervertebral disc endoprosthesis. The invention contains two rigid opposing shells, each having an outer surface adapted to engage the surfaces of the bones of a joint in such a way that the shells are immobilized by friction between their outer surfaces and the surfaces of the bone. These outer surfaces are sufficiently rough that large frictional forces strongly resist any slippage between the outer surface and the bone surfaces in the joint. They may be convex, and when inserted into a milled concavity, are immediately mechanically stable. Desirably, the outer surfaces of the shells are adapted to allow for bony ingrowth, which further stabilizes the shells in place. The inner surfaces of the shells are relatively smooth, and adapted to slide easily across a portion of the outer surface of a central body disposed between the shells. The central body has a shape that cooperates with the shape of the inner surface of the shell so as to provide a range of motion similar to that provided by a healthy joint. A flexible sheath extends between edges of the opposing shells. The inner surface of this sheath, together with the inner surfaces of the rigid shells, defines a cavity encasing the central body. At least a portion of this cavity is filled with a fluid lubricant, further decreasing the frictional force between inner surfaces of the shell and the surface of the central body.
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Citations
119 Claims
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1. A surgical implant suitable for use in a joint between the surfaces of two bones, comprising:
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two rigid opposing shells, each having an outer surface adapted to engage the surfaces of the bones of a joint in such a way that movement of the shell relative to the bone surface is resisted by friction between the outer surface and the surface of the bone;
an inner surface that is smoother than the outer surface; and
an edge between the outer surface and the inner surface;
a deformable, resilient central body disposed between the inner surfaces of the shells comprising an outer surface, at least a portion of which has a shape that complements and articulates with the shape of the inner surface of one or both rigid opposing shells to allow the inner surface of the rigid opposing shell and the outer surface of the central body to move easily with respect to each other within a constrained range of motion, but to resist such movement outside the constrained range of motion. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 118)
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21. A vertebral endoprosthesis, comprising:
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an upper and a lower rigid, opposed, biocompatible shell, each comprising;
an outer, rough surface;
an inner, smooth concave surface; and
an edge between the surfaces;
wherein the inner smooth surface of at least one of the shells comprises a motion limiting device;
a deformable, resilient central body disposed between the inner, smooth concave surfaces of the upper and lower shells, comprising;
a smooth convex upper surface adjacent to the inner smooth concave surface of the upper shell and a smooth convex lower surface adjacent to the inner smooth concave surface of the lower shell;
motion limiting device disposed on at least one of the smooth convex upper and lower surfaces adapted to contact the motion limiting device and limit the relative motion of the shell with respect to the central body. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40)
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41. A vertebral endoprosthesis, comprising:
an upper and a lower rigid, opposed biocompatible concavo-convex shell, each comprising;
an outer, rough convex surface, comprising a porous coating of a biocompatible material;
an inner concave surface, comprising;
a smooth contact area; and
an axial post extending toward the opposing shell; and
an edge between the surfaces, comprising;
a circumferential groove adapted to receive a retaining ring;
a first ridge circumscribing the contact area of the inner concave surface and extending axially toward the opposing shell;
a tab extending axially away from the opposing shell, and comprising an opening adapted to releasably engage a tool for manipulating, inserting, or removing the endoprosthesis;
a closable passage between the outer surface and the inner surface of the shell;
a deformable, resilient central body disposed between the inner, smooth concave surfaces of the upper and lower shells, comprising;
smooth convex upper and lower surfaces complementary and adjacent to the smooth contact area of the inner surfaces of the respective upper and lower shells;
a shoulder circumscribing each of the smooth convex upper and lower surfaces and adapted to contact the first ridge of the adjacent shell and limit the relative motion of the shell with respect to the central body;
a laterally extending equatorial ridge disposed between the first ridge of the upper concavo-convex shell and the first ridge of the lower concavo-convex shell;
an opening in the upper and lower convex contact surfaces adapted to receive the axial post of the inner surface of each shell;
an elastic sheath disposed between the upper and lower shells and external to the central body, comprising an inner surface, an outer surface, an upper edge attached to the upper shell, and a lower edge attached to the lower shell, wherein the inner surface of the sheath and the inner surfaces of the shells define an enclosed cavity;
an upper retaining ring of a biocompatible material disposed in the circumferential groove in the upper concavo-convex shell and securing the upper edge of the elastic sheath to the shell and a lower retaining ring of a biocompatible material disposed in the circumferential groove of the lower concavo-convex shell and securing the lower edge of the sheath to the shell. - View Dependent Claims (42, 43, 44, 46, 49)
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45. A bone joint implant comprising an encapsulated central body having a central axial opening therein.
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47. The implant of 46 wherein the central body has an upper and a lower convex contact surface.
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48. A bone joint implant comprising a central body positioned between two shells, wherein the central body has a central axial opening therein.
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50. The implant of 49 wherein the central body has an upper and a lower convex contact surface.
- 51. A bone joint implant comprising a central body positioned between two shells, wherein the central body has a shoulder consisting of an indentation extending around at least a portion of its perimeter.
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56. A bone joint implant comprising a central body positioned between two shells, wherein the central body has an upper and a lower contact surface, wherein an upper shoulder extends around a portion of the perimeter of the upper contact surface and a lower shoulder extends around a portion of the perimeter of the lower contact surface.
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59. A bone joint implant comprising an encapsulated central body having an upper and a lower contact surface, wherein an upper shoulder extends around a portion of the perimeter of the upper contact surface and a lower shoulder extends around a portion of the perimeter of the lower contact surface.
- 62. A bone joint implant comprising a central body positioned between two shells, wherein each shell has a smooth inner surface that contacts the central body
- 64. A bone joint implant comprising a central body positioned between two shells, wherein each shell has a machined or polished inner surface that contacts the central body.
- 66. A bone joint implant comprising a central body positioned between two shells, wherein at least one shell has an outer surface that is coated to promote bony ingrowth.
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72. A bone joint implant comprising a central body positioned between two shells, wherein at least one shell has a rough outer surface.
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73. A bone joint implant comprising a central body positioned between two shells, wherein at least on shell has an outer surface that is coated to provide friction between the outer surface and bone.
- 74. A bone joint implant comprising a central body and a lubricant encapsulated within a structure having at least one opening for the introduction of the lubricant into the structure.
- 77. A bone joint implant comprising a central body positioned between two shells, wherein at least one shell includes an inner surface having a central retaining post extending therefrom and adapted to allow rotation of the shells relative to the central body.
- 80. A bone joint implant comprising a central body positioned between two shells, wherein at least one shell has an edge that includes a radial stop extending generally axially from a portion thereof.
- 86. A bone joint implant comprising a two shells interconnected by a sleeve to form a cavity therein, and a central body having at least one indentation therein positioned within the cavity, wherein at least one of the shells includes a retaining post that extends into the indentation and at least one of the shells includes an opening to allow introduction of a lubricant into the cavity.
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90. A method of introducing the lubricant into the implant of 86 comprising slightly compressing the implant to remove excess air, and injecting the lubricant into the opening.
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93. A bone joint implant comprising an elastomeric central body positioned between two shells wherein the central body is impregnated with a surface hardening substance.
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94. A bone joint implant comprising an encapsulated elastomeric central body that is impregnated with a surface hardening substance.
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95. A bone joint implant comprising an encapsulated central body that is impregnated with a surface lubricity increasing material.
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96. A bone joint implant comprising a central body positioned between two shells, wherein the central body is impregnated with a surface lubricity increasing material.
- 97. A bone joint implant comprising a central body consisting of one or more integral materials such that the central body has a surface region that is harder than an interior region.
- 101. A bone joint implant comprising a central body having a coating thereon wherein the coating material has a different hardness from the material used to form the central body.
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103. A bone joint implant comprising a central body having a coating thereon, wherein the coating increases the surface lubricity of the central body.
- 104. A bone joint implant comprising a central body positioned between two shells, wherein the central body has a polymer coating thereon.
- 111. A bone joint implant comprising a central body having a coating thereon characterized in that the coating material is different from the material used to form the central body.
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112. A bone joint implant comprising a central body having a coating thereon characterized in that the coating material is the same as the material used to form the central body.
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114. A system of bone joint implants of varying sizes, wherein each implant comprises:
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a central body positioned between an upper shell and a lower shell, wherein at least a portion of the outer surface of each shell is convex and at least a portion of the inner surface of each shell is concave; and
the convex portion of the outer surface and the concave portion of the inner surface of the shells can each be described as a quadric surface, such that wherein (±
a,0,0), (0,±
b,0), and (0,0,±
c) represent the x, y, and z intercepts of the surface, respectively, and may be the same or different for the outer and inner surfaces.
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119. The system of bone joint implants, wherein a, b and c are the same for the outer and inner surfaces.
Specification