Bone implant with a surface anchoring structure

• US 8,888,862 B2
• Filed: 05/19/2010
• Issued: 11/18/2014
• Est. Priority Date: 05/19/2009
• Status: Active Grant

• Current Assignee: National University of Ireland Galway
• Original Assignee: National University of Ireland Galway
• Inventors: McDonnell, Patrick, Harrison, Noel
• Primary Examiner(s): Sweet, Thomas J
• Assistant Examiner(s): PRESTON, REBECCA STRASZHEIM
• Application Number:
  US12/783,025
• Publication Number:
  US 20100298950A1
• Time in Patent Office: 1,644 Days
• Field of Search: None
• US Class Current: 623/23.5
• CPC Class Codes: A61F 2/30771 applied in original prostheses, e.g. holes or grooves
• CPC Class Codes: A61F 2/3094 Designing or manufacturing processes
• CPC Class Codes: A61F 2/36 Femoral heads ; Femoral endoprostheses
• CPC Class Codes: A61F 2/3662 Femoral shafts
• CPC Class Codes: A61F 2002/30011 differing in porosity
• CPC Class Codes: A61F 2002/30113 circular
• CPC Class Codes: A61F 2002/30156 triangular
• CPC Class Codes: A61F 2002/30179 X-shaped
• CPC Class Codes: A61F 2002/30225 Flat cylinders, i.e. discs
• CPC Class Codes: A61F 2002/30322 differing in surface structures
• CPC Class Codes: A61F 2002/30808 parallel
• CPC Class Codes: A61F 2002/30812 perpendicular with respect to each other
• CPC Class Codes: A61F 2002/30841 Sharp anchoring protrusions for impaction into the bone, e.g. sharp pins, spikes
• CPC Class Codes: A61F 2002/30892 parallel
• CPC Class Codes: A61F 2002/30909 Nets
• CPC Class Codes: A61F 2002/3092 having an open-celled or open-pored structure
• CPC Class Codes: A61F 2002/30952 using CAD-CAM techniques or NC-techniques
• CPC Class Codes: A61F 2002/30968 Sintering
• CPC Class Codes: A61F 2002/3097 using laser
• CPC Class Codes: A61F 2002/3611 Heads or epiphyseal parts of femur
• CPC Class Codes: A61F 2002/3625 : Necks
• CPC Class Codes: A61F 2002/3631 : with an integral complete or partial peripheral collar or bearing shoulder at its base
• CPC Class Codes: A61F 2002/4681 : by applying mechanical shocks, e.g. by hammering
• CPC Class Codes: A61F 2230/0006 : circular
• CPC Class Codes: A61F 2230/0023 : triangular
• CPC Class Codes: A61F 2230/0058 : X-shaped
• CPC Class Codes: A61F 2230/0069 : cylindrical
• CPC Class Codes: A61F 2250/0024 : made from both porous and non-porous parts, e.g. adjacent parts
• CPC Class Codes: A61F 2250/0026 : differing in surface structures
• CPC Class Codes: A61F 2310/00011 : Metals or alloys
• 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

Abstract

A bone implant comprises a core 10 having an integral anchoring structure 12 at its surface. The structure 12 comprises an array of upwardly extending mutually spaced pointed claw-like teeth 14 for digging into bone to which the implant is to be attached, and a network of pores 16 underlying the array and communicating with the exterior of the surface via openings 18 between the teeth, the pores allowing for the circulation of nutrients to promote bone growth.

Claims

1. A permanent bone implant comprising a stem extending between a proximal end and a distal end, the stem having an integral anchoring structure at a surface of the stem, wherein said distal end has a smaller cross section than said proximal end, the structure comprising an array of mutually spaced pointed teeth formed along at least a portion of the length of the stem, each tooth forming an overhang generally in the form of a claw having an upper surface with convergent edges defining a point of the tooth extending towards said distal end and for digging into a bone in a direction in which the stem is to be attached, and a network of pores underlying the array and communicating with an exterior of the surface via openings between the teeth, the network of pores allowing for circulation of nutrients to promote bone growth, wherein the structure comprises a grid of intersecting struts supported above a core of the implant by a plurality of pillars, each pillar intersecting the grid at respective intersections of the struts and extending upwardly beyond the strut intersection to form the teeth.

2. A bone implant as claimed in claim 1, wherein the openings between the teeth allow growth of bone into the network of pores.

3. A bone implant as claimed in claim 1, wherein the network of pores are substantially fully interconnected.

4. A bone implant as claimed in claim 1, wherein the claws have a common orientation over at least a substantial area of the structure.

5. A bone implant as claimed in claim 4, wherein an upper surface portion of each claw is inclined upwardly to the point of the tooth.

6. A bone implant as claimed in claim 4, wherein an upper surface portion of each claw is substantially parallel to the core of the implant.

7. A bone implant as claimed in claim 1, wherein each claw has a substantially triangular upper surface.

8. A bone implant as claimed in claim 1, wherein junctions between the intersecting struts and pillars, and between the pillars and underlying core, are filleted.

9. A bone implant as claimed in claim 1, wherein the structure is made integral with the core of the implant by a rapid prototyping process such as direct metal laser sintering or electron beam melting.

10. A bone implant as claimed in claim 1, wherein the anchoring structure and the core of the implant are made of titanium, titanium alloy, cobalt chromium or other biocompatible metal material.

11. A bone implant as claimed in claim 1, wherein said proximal end comprises a component of an articulated joint.