Graduated porosity implant for fibro-osseous integration

• US 5,489,306 A
• Filed: 01/03/1995
• Issued: 02/06/1996
• Est. Priority Date: 01/03/1995
• Status: Expired due to Fees

• Current Assignee: Jerrold M. Gorski
• Original Assignee: Jerrold M. Gorski
• Inventors: Gorski, Jerrold M.
• Primary Examiner(s): ISABELLA, DAVID J
• Application Number:
  US08/367,598
• Time in Patent Office: 399 Days
• Field of Search: 623/16, 623/18, 623/20, 623/22, 623/23, 623/66
• US Class Current: 623/23.55
• CPC Class Codes: A61F 2/28 Bones joints A61F2/30
• CPC Class Codes: A61F 2/30767 Special external or bone-contacting surface, e.g. coating for improving bone ingrowth
• 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 2002/30769 madreporic
• CPC Class Codes: A61F 2002/3631 with an integral complete or partial peripheral collar or bearing shoulder at its base
• CPC Class Codes: A61F 2002/368 with lateral apertures, bores, holes or openings, e.g. for reducing the mass, for receiving fixation screws or for communicating with the inside of a hollow shaft
• CPC Class Codes: A61F 2250/0023 differing in porosity
• 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 2310/00059 Chromium or Cr-based alloys
• CPC Class Codes: A61F 2310/00401 Coating made of iron, of stainless steel or of other Fe-based alloys
• CPC Class Codes: A61F 2310/00407 Coating made of titanium or of Ti-based alloys
• CPC Class Codes: A61F 2310/00413 Coating made of cobalt or of Co-based alloys
• CPC Class Codes: A61F 2310/00449 Coating made of chromium or Cr-based alloys
• CPC Class Codes: A61L 27/042 Iron or iron alloys
• CPC Class Codes: A61L 27/045 Cobalt or cobalt alloys
• CPC Class Codes: A61L 27/06 : Titanium or titanium alloys
• CPC Class Codes: A61L 27/30 : Inorganic materials
• CPC Class Codes: A61L 27/56 : Porous materials, e.g. foams or sponges
• CPC Class Codes: B22F 7/002 : of porous nature

Abstract

A surgical prosthetic implant comprises a metallic substrate for insertion into the cavity of a long bone. A porous coating is provided on the substrate for encouraging bone and tissue ingrowth. The porous coating comprises at least a layer of particles of metallic material, which may be of the same material as the substrate. Graduated sized particles are used from proximal to distal ends of the implant creating graduated pore size between particles from proximal to distal ends. At a first zone at a proximal end of the substrate, the particles have a pore size in the range of approximately 325-425 microns for optimal bone-to-implant load transfer. At a second zone, advancing toward a distal end of the substrate, the particles have a pore size in the range of approximately 250-325 microns for significant bone ingrowth in a shorter time interval. At a third zone, the particles have a pore size in the range of approximately 175-250 microns for some bone ingrowth and some soft tissue ingrowth. At a fourth zone, the particles have a pore size in the range of approximately 100-175 microns for optimal soft tissue ingrowth with minimal bone ingrowth. At a fifth zone, the particles have a pore size of less than approximately 100 microns for optimal soft tissue ingrowth without permitting bone ingrowth. The porous coating may be of the same material as the substrate, which may be of stainless steel, titanium, titanium alloys, or chromium-cobalt alloys.

Claims

1. A surgical prosthetic implant comprising:

a metallic substrate extending between proximal and distal ends for insertion into the cavity of a long bone;

a porous coating on said substrate for encouraging bone and tissue ingrowth comprising at least a layer of particles of metallic material adhered to and extending over substantially the entire surface of said substrate wherein the size of said particles is graduated from a first zone at said proximal end at which said particles have a first predetermined pore size in the range of approximately 325-425 microns to achieve optimal bone-to-implant load transfer, then continuing toward said distal end, through a second zone at which said particles have a second predetermined pore size in the range of approximately 250-325 microns to achieve significant bone ingrowth in a shorter time interval, through a third zone at which said particles have a third predetermined pore size in the range of approximately 175-250 microns to permit some bone ingrowth while also permitting some soft tissue ingrowth;

through a fourth zone at which said particles have a fourth predetermined pore size in the range of approximately 100-175 microns for increased soft tissue ingrowth with minimal bone ingrowth;

to a fifth zone at which said particles have a fifth predetermined pore size of less than approximately 100 microns for optimal soft tissue ingrowth without permitting bone ingrowth.

2. A surgical prosthetic implant as set forth in claim 1

wherein said particles of said porous coating are of the same material as said substrate;

and

wherein said coating and said substrate are both biologically compatible with human bone and soft tissue.

3. A surgical prosthetic implant as set forth in claim 1

wherein the metal of said substrate is selected from the group consisting of stainless steel, titanium, titanium alloys, and chromium-cobalt alloys.

4. A surgical prosthetic implant comprising:

a metallic substrate for insertion into the cavity of a long bone, said substrate having a proximal zone, a distal zone distant from said proximal zone, and an intermediate zone between said proximal and distal zones;

a porous coating on said substrate for encouraging bone and soft tissue ingrowth comprising at least a layer of particles of metallic material adhered to and extending over substantially the entire surface of said substrate wherein the size of said particles is graduated from said proximal zone at which said particles are sized for optimal bone-to-implant load transfer, through said intermediate zone at which said particles are sized to permit some bone ingrowth while also permitting some soft tissue ingrowth, to said distal zone at which said particles are sized for optimal soft tissue ingrowth without permitting bone ingrowth.

5. A surgical prosthetic implant as set forth in claim 4

wherein said particles of said porous coating are of the same material as said substrate;

and

wherein said coating and said substrate are both biologically compatible with human bone and soft tissue.

6. A surgical prosthetic implant as set forth in claim 4

wherein the metal of said substrate is selected from the group consisting of stainless steel, titanium, titanium alloys, and chromium-cobalt alloys.

7. A surgical prosthetic implant comprising:

a metallic substrate extending between proximal and distal ends for insertion into the cavity of a long bone, said substrate having a proximal zone at said proximal end and a distal zone at said distal end distant from said proximal zone; and

a porous coating on said substrate for encouraging bone and tissue ingrowth comprising at least a layer of particles of metallic material adhered to and extending over substantially the entire surface of said substrate wherein the size of said particles is graduated from said first zone at which said particles have one predetermined size range for optimal bone-to-implant load transfer to said distal zone at which said particles have another predetermined size range for optimal soft tissue ingrowth without permitting bone ingrowth.

8. A surgical prosthetic implant as set forth in claim 7

wherein said particles of said porous coating are of the same material as said substrate;

and

wherein said coating and said substrate are both biologically compatible with human bone and soft tissue.

9. A surgical prosthetic implant as set forth in claim 7

wherein the metal of said substrate is selected from the group consisting of stainless steel, titanium, titanium alloys, and chromium-cobalt alloys.