US 5,489,306 A · Graduated porosity implant for fibro-osseous integration

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.

Claims9

Dependent claims

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.

1 more element

Dependencies are inferred from the claim text.

Graduated porosity implant for fibro-osseous integration

Life of this patent

Graduated porosity implant for fibro-osseous integration

Life of this patent

Abstract

Claims9