Patent US5201766A successfully refreshed from Google Patents.
US5201766A
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Prosthetic device with porous matrix and method of manufacture
Assignee: Smith and Nephew Inc
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Filing: 1991-02-28
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Granted: 1993-04-13
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Expires: 2011-02-28
Abstract
Abstract A method of forming a porous matrix and a porous matrix having a uniform surface, depth and a controlled microstructure is provided. The uniform matrix to provide for fixation of prosthetic device by tissue ingrowth is formed through the action of heat and pressure in a hot isostatic pressing process. Such a process provides a porous matrix having a uniform surface and depth due to the isostatic pressure applied and a controlled microstructure of the material due to the relatively low temperatures employed.
Inventors
- 👤 Frederick S. Georgette
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 19:09
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/30767; A61F2/30771; A61F2/30907; A61F2/32; A61F2/36; A61F2/3662; A61F2/367; A61L; A61L27/00; A61L27/02; A61L27/04; A61L27/06; A61L27/28; A61L27/30; A61L27/306; B; B22; B22F; B22F7/00; B22F7/002; A61F2/3094; A61F2002/30001; A61F2002/30316; A61F2002/30317; A61F2002/30322; A61F2002/30769; A61F2002/30838; A61F2002/30929; A61F2250/00; A61F2250/0014; A61F2250/0026; A61F2310/00; A61F2310/00005; A61F2310/00011; A61F2310/00023; A61F2310/00389; A61F2310/00395; A61F2310/00407; Y; Y10; Y10S; Y10S623/00; Y10S623/92; Y10S623/923
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
250 words
A method of forming a porous matrix on a portion of the outer surface of a prosthetic device, comprising the steps of: (a) providing a prosthetic device having an outer surface portion on which a porous matrix is to be formed; (b) attaching an enclosure around said outer surface portion that conforms to the shape of the prosthetic device outer surface and spaced therefrom, said enclosure having a smooth inner surface for engaging metallic particles contained within the enclosure, and wherein the enclosure is formed of a collapsible material capable of withstanding elevated temperature; (c) charging the space between the enclosure inner surface portion and the outer surface of the prosthetic device with metallic particles; (d) evacuating substantially all air from said enclosure; (e) subjecting the outer surface of said enclosure to an elevated pressure in an atmosphere of inert gas at an elevated temperature; (f) wherein in step "e" said pressure and temperature are sufficient to fuse the particles together and to said portion of the prosthetic device so that the inner surface of the collapsed enclosure deforms at least some of the metallic particles to define a smooth but porous outer surface of the prosthetic collapsed metallic particles at a temperature below that which would transform the microstructure of the metallic substrate to a weakened state; (g) cooling said prosthetic device; (h) removing said enclosure to expose said particles; and (i) wherein in step "h" the prosthesis outer surface remains smooth but porous after removal of the enclosure.
Claim 2
Independent Claim
250 words
A method of forming a porous matrix on a portion of the outer surface of a prosthetic device, comprising the steps of: (a) providing a prosthetic device having an outer surface portion on which a porous matrix is to be formed; (b) attaching an enclosure around said outer surface portion that conforms to the shape of the prosthetic device outer surface and spaced therefrom, said enclosure having a smooth inner surface for engaging metallic particles contained within the enclosure, and wherein the enclosure is formed of a collapsible material capable of withstanding elevated temperature; (c) charging the space between the enclosure inner surface portion and the outer surface of the prosthetic device with metallic particles; (d) evacuating substantially all air from said enclosure; (e) subjecting the outer surface of said enclosure to an elevated pressure in an atmosphere of inert gas at an elevated temperature; (f) wherein in step "e" said pressure and temperature are sufficient to fuse the particles together and to said portion of the prosthetic device so that the inner surface of the collapsed enclosure deforms at least some of the metallic particles to define a smooth but porous outer surface of the prosthetic collapsed metallic particles at a temperature below that which would transform the microstructure of the metallic substrate to a weakened state; (g) cooling said prosthetic device; (h) removing said enclosure to expose said particles; and (i) wherein in step "h" the prosthesis outer surface remains smooth but porous after removal of the enclosure.
Claim 3
Dependent Claim
33 words
The method of claim 1, wherein said portion includes a cavity formed on the outer surface of the prosthetic device and conforming to the shape of the prosthetic device on multiple sides thereof.
Claim 4
Dependent Claim
19 words
The method of claim 1, wherein said prosthetic device and metallic particles are formed of a titanium alloy, Ti-6Al-4V.
Claim 5
Dependent Claim
27 words
The method of claim 1, wherein said enclosure is formed of a titanium alloy foil lined with molybdenum on the side in contact with the metallic particles.
Claim 6
Dependent Claim
33 words
The method of claim 1, wherein the metallic particles are spherical in shape and in step "f" the particles are flattened at the surface of the prosthesis to define the smooth outer surface.
Claim 7
Dependent Claim
16 words
The method of claim 1, wherein said particles are of a mesh from 20 to 18.
Claim 8
Dependent Claim
22 words
The method of claim 3, wherein step (e) is performed at a temperature below the beta transition temperature of the particle material.
Claim 9
Dependent Claim
17 words
The method of claim 7, wherein step (e) is performed at a temperature of about 900° C.
Claim 10
Dependent Claim
15 words
The method of claim 1, wherein step (e) is performed in a hot isostatic press.
Claim 11
Dependent Claim
11 words
The method of claim 1, wherein said inert gas is argon.
Claim 12
Dependent Claim
19 words
The method of claim 9, wherein said hot isostatic process is performed at a pressure between about 300-500 psi.
Claim 13
Dependent Claim
15 words
The method of claim 9, wherein the step (e) is maintained for about 1-4 hours.
Claim 14
Dependent Claim
29 words
The method of claim 1, and further including the step of heat treating the porous matrix in a fan quenched vacuum furnace to prevent surface oxidation of the particles.
Claim 15
Dependent Claim
52 words
The method of claim 1, wherein said prosthetic device is a hip prosthesis with a femoral stem portion having medial and lateral side portions, and said porous matrix is applied to the proximal region of said femoral stem and on multiple sides thereof including at least medial and lateral side portions thereof.
Claim 16
Independent Claim
318 words
A method of forming a porous matrix on a portion of outer surface of a hip prosthesis having a lower elongated distal stem, a proximate portion with anterior and posterior sides, and a neck region, comprising the steps of: (a) providing a hip prosthesis having an outer surface portion on which a porous matrix is to be formed and including a lower stem proximate portion and a neck region; (b) attaching a metallic enclosure around said outer surface portion at the mid portion thereof, terminating below the neck and adjacent the stem, the enclosure conforming generally to the shape of the his prosthesis proximate portion and extending over at least the anterior and posterior sides thereof and spaced therefrom, said enclosure having a smooth inner surface portion and being formed of a collapsible material capable of withstanding the temperature of step (e); (c) charging the space between the enclosure inner surface portion and the outer surface of the prosthetic device with metallic particles; (d) evacuating substantially all air from said enclosure; (e) subjecting the outer surface of said enclosure to an elevated pressure in an atmosphere of inert gas at an elevated temperature; (f) wherein the step "e" said pressure and temperature are sufficient to fuse the particles together and to said portion of the hip prosthesis so that the inner surface of the collapsed enclosure deforms at least some of the metallic particles to define a smooth but porous outer surface of the prosthetic collapsed metallic particles at a temperature below that which would transform the microstructure of the metallic substrate to a weakened state; (g) cooling said hip prosthesis device; (h) removing said enclosure to expose said particles; and (i) wherein in step "f" a plurality of the particles are flattened at the outer surface to define the smooth surface, the smooth outer surface remaining smooth but porous after removal of the enclosure in step "h".
Claim 17
Independent Claim
318 words
A method of forming a porous matrix on a portion of outer surface of a hip prosthesis having a lower elongated distal stem, a proximate portion with anterior and posterior sides, and a neck region, comprising the steps of: (a) providing a hip prosthesis having an outer surface portion on which a porous matrix is to be formed and including a lower stem proximate portion and a neck region; (b) attaching a metallic enclosure around said outer surface portion at the mid portion thereof, terminating below the neck and adjacent the stem, the enclosure conforming generally to the shape of the his prosthesis proximate portion and extending over at least the anterior and posterior sides thereof and spaced therefrom, said enclosure having a smooth inner surface portion and being formed of a collapsible material capable of withstanding the temperature of step (e); (c) charging the space between the enclosure inner surface portion and the outer surface of the prosthetic device with metallic particles; (d) evacuating substantially all air from said enclosure; (e) subjecting the outer surface of said enclosure to an elevated pressure in an atmosphere of inert gas at an elevated temperature; (f) wherein the step "e" said pressure and temperature are sufficient to fuse the particles together and to said portion of the hip prosthesis so that the inner surface of the collapsed enclosure deforms at least some of the metallic particles to define a smooth but porous outer surface of the prosthetic collapsed metallic particles at a temperature below that which would transform the microstructure of the metallic substrate to a weakened state; (g) cooling said hip prosthesis device; (h) removing said enclosure to expose said particles; and (i) wherein in step "f" a plurality of the particles are flattened at the outer surface to define the smooth surface, the smooth outer surface remaining smooth but porous after removal of the enclosure in step "h".
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1996-04-12 | 1996-10-12 | 1997-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2000-04-12 | 2000-10-12 | 2001-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2004-04-12 | 2004-10-12 | 2005-04-13 | $7700.00 | Window Closed / Lapsed |