Ceramic/metallic articulation component and prosthesis

• US 6,105,235 A
• Filed: 06/01/1995
• Issued: 08/22/2000
• Est. Priority Date: 04/28/1994
• Status: Expired due to Fees

• Current Assignee: Hitachi Global Storage Technologies Japan Limited (Hitachi, Ltd.)
• Original Assignee: Johnson & Johnson Professional Company Incorporated (Johnson & Johnson)
• Inventors: Caldarise, Salvatore
• Primary Examiner(s): Hughes, S. Thomas
• Assistant Examiner(s): BUTLER, MARC WINSTON
• Application Number:
  US08/456,779
• Time in Patent Office: 1,909 Days
• Field of Search: 29/527.5, 29/530, 29/898.047, 29/898.049, 29/898.05, 29/898.043, 29/898.048, 403/135, 403/9, 623/18, 623/16, 623/22, 623/23, 164/98, 164/103, 428/621
• US Class Current: 29/527.5
• 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 2/30965 Reinforcing the prosthesis by embedding particles or fibres during moulding or dipping
• CPC Class Codes: A61F 2/32 for the hip
• CPC Class Codes: A61F 2/34 Acetabular cups
• CPC Class Codes: A61F 2/3609 Femoral heads or necks; Connections of endoprosthetic heads or necks to endoprosthetic femoral shafts A61F2/3601 takes precedence
• 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 2/38 for elbows or knees
• CPC Class Codes: A61F 2002/30004 the prosthesis being made from materials having different values of a given property at different locations within the same prosthesis
• CPC Class Codes: A61F 2002/30289 helically-coiled
• CPC Class Codes: A61F 2002/30301 saddle-shaped
• CPC Class Codes: A61F 2002/30322 differing in surface structures
• CPC Class Codes: A61F 2002/30332 Conically- or frustoconically-shaped protrusion and recess
• CPC Class Codes: A61F 2002/30387 Dovetail connection
• CPC Class Codes: A61F 2002/30602 Shaft made of a bundle of anchoring rods or bristles, e.g. fasciculate shaft
• CPC Class Codes: A61F 2002/30624 Hinged joint, e.g. with transverse axle restricting the movement
• CPC Class Codes: A61F 2002/30934 Special articulating surfaces
• CPC Class Codes: A61F 2002/30952 using CAD-CAM techniques or NC-techniques
• CPC Class Codes: A61F 2002/30957 using a positive or a negative model, e.g. moulds
• CPC Class Codes: A61F 2002/30973 : Two joined adjacent layers having complementary interlocking protrusions and recesses
• CPC Class Codes: A61F 2002/3429 : with an integral peripheral collar or flange, e.g. oriented away from the shell centre line
• CPC Class Codes: A61F 2002/3611 : Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/3613 : with lateral or oblique apertures, holes or openings
• CPC Class Codes: A61F 2002/3625 : Necks
• CPC Class Codes: A61F 2002/365 : Connections of heads to necks
• CPC Class Codes: A61F 2002/5039 : allowing only for single rotation
• CPC Class Codes: A61F 2002/5041 : having bearing bushes between the rotating parts
• CPC Class Codes: A61F 2220/0025 : Connections or couplings between prosthetic parts, e.g. between modular parts; Connecting elements
• CPC Class Codes: A61F 2220/0033 : made by longitudinally pushing a protrusion into a complementary-shaped recess, e.g. held by friction fit
• CPC Class Codes: A61F 2230/0091 : helically-coiled or spirally-coiled, i.e. having a 2-D spiral cross-section
• CPC Class Codes: A61F 2230/0095 : Saddle-shaped
• CPC Class Codes: A61F 2250/0014 : having different values of a given property or geometrical feature, e.g. mechanical property or material property, at different locations within the same prosthesis
• CPC Class Codes: A61F 2250/0026 : differing in surface structures
• 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: B29L 2031/7532 : Artificial members, protheses
• CPC Class Codes: B33Y 80/00 : Products made by additive manufacturing
• CPC Class Codes: Y10T 29/49988 : Metal casting

Abstract

An implantable bone prosthesis includes portions of two different materials which interfit with each other to form a unitary article having hard wear surface portions and strong, stiff portions for structural support. These portions are preferably formed of ceramic and of metal, respectively. The prosthesis is formed by making a multiply connected ceramic wear surface element having openings or passages therethrough, and casting the remainder of the prosthesis extending in the openings to form a mating or dendritic support or a frame interdigitated and interlocked with the ceramic wear surface. The frame may be shaped so that it contracts along a direction of shrinkage, as the casting cools, without binding against the ceramic body. In a spherical shell, such as used for the weight-bearing acetabular shell or ball joint of a hip, this is achieved with short, radially-directed interlock elements. Other connections of the two materials may include tapered bores, dovetail channels, fern-like dendritic structures, or the like. Ball and socket, trunion and other articulations are fabricated with high strength and durable wear properties.

Claims

1. A method of forming an articulation component of an implantable bone prosthesis, such method comprising:

forming a ceramic wear surface body comprising a wear surface of the implantable bone prosthesis, said wear surface being configured as a bearing surface for contacting and articulating relative to another surface

forming a casting mold by a three-dimensional printing process about a region which contacts said wear surface body, and

forming a metal skeletal structural support against the wear surface body by casting the skeletal support in said casting mold, wherein the step of forming said casting mold includes forming with a shape such that the metal skeletal structural support cast therein cools without stresses of contraction transmitting destructive shear forces to or fracturing the ceramic wear surface body, and such that the metal skeletal structural support is integrally affixed to and supports the wear surface body and said wear surface of said wear surface body is exposed to contact and articulate relative to said another surface.

2. The method of claim 1 wherein the wear surface body has a wear surface and an opposed interfacing surface having one or more recesses therein.

3. The method of claim 2 wherein the step of casting a skeletal support involves infiltrating the recesses with a molten casting metal.

4. The method of claim 1 wherein the wear surface body is formed by a three-dimensional printing process.

5. The method of claim 1 wherein the casting mold is integrally formed with the wear surface body.

6. The method of claim 1 wherein the casting mold is formed separately from the wear surface body and wherein the method further comprises the step of attaching the casting mold to the wear surface body.

7. The method of claim 1 wherein the ceramic wear surface body has at least one of the properties of:

small grain size, high hardness, long wear properties and corrosion resistance and the casting step comprises filling the casting mold with a metal having at least one of the properties of;

high stiffness, tensile strength, durability and toughness.

8. The method of claim 7 wherein the metal is a cobalt chromium alloy.

9. The method of claim 7 further comprising the step of removing the casting mold following the casting step.

10. A method of forming an articulation component of an implantable bone prosthesis, comprising the steps of:

forming a ceramic wear surface body comprising a wear surface of the implantable bone prosthesis, said wear surface being configured as a bearing surface for contacting and articulating relative to another surface;

forming a casting mold in contact with the wear surface body; and

forming a metal skeletal structural support by casting the metal skeletal structural support against the wear surface body in the casting mold, wherein the step of forming said casting mold includes forming with a shape such that the metal skeletal structural support cast therein cools without stresses of contraction transmitting destructive shear forces to or fracturing the ceramic wear surface body, and such that the metal skeletal structural support is integrally affixed to and supports the wear surface body and said wear surface of said wear surface body is exposed to contact and articulate relative to said another surface.

11. The method of claim 10 wherein the wear surface body is formed by a three dimensional printing process.

12. The method of claim 10 wherein the casting mold is formed by a three-dimensional printing process.

13. The method of claim 10 wherein the ceramic wear surface body has at least one of the properties of:

small grain size, high hardness, long wear properties and corrosion resistance and the casting step comprises filling the casting mold with a metal having at least one of the properties of;

high stiffness, tensile strength, durability and toughness.