US5376123A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Adaptable stem for endoprosthesis
Assignee: AO-Forschungsinstitut
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Filing: 1993-04-30
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Granted: 1994-12-27
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Expires: 2013-04-30
Abstract
Abstract A stem for an endoprosthesis to be anchored in a bone (3) comprises a chamber (4) which surrounds the stem periprosthetically, which can be sealed in a pressure tight manner and which can be expanded with a thermoplastic or thermostable filling material (16). The rigid stem (1) of the endoprosthesis is connected mechanically to the bone (3) via the expandable chamber (4) by means of the filling material (16). The filling material is isolated from the bone (3), however, by the wall of the pressure-tight chamber (4). This makes it possible to ensure that the outer wall of the chamber (4) adjacent to the bone is extremely biocompatible.
Inventors
- 👤 Kaj Klaue
- 👤 Jean L. Chareire
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 03:52
CPC Classifications
A; A61; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/30767; A61F2/30907; A61B; A61B17/00; A61B17/56; A61B17/58; A61B17/88; A61B17/8802; A61B17/8841; A61F2/32; A61F2/36; A61F2/3662; A61B17/68; A61B17/70; A61B17/7097; A61B17/7098; A61F2/30721; A61F2/30723; A61F2/3094; A61F2/30965; A61F2/367; A61F2002/30001; A61F2002/30003; A61F2002/3006; A61F2002/30065; A61F2002/30067; A61F2002/30108; A61F2002/3011; A61F2002/30112; A61F2002/30125; A61F2002/30316; A61F2002/30329; A61F2002/30405; A61F2002/30535; A61F2002/30565; A61F2002/30566; A61F2002/30579; A61F2002/30581; A61F2002/30583; A61F2002/30586; A61F2/30771; A61F2002/30772; A61F2002/30774; A61F2002/3082; A61F2002/30917; A61F2002/30919; A61F2002/3678; A61F2002/3694; A61F2/46; A61F2002/4631; A61F2210/00; A61F2210/0085; A61F2220/00; A61F2220/0025; A61F2230/00; A61F2230/0002; A61F2230/0004; A61F2230/0008; A61F2310/00; A61F2310/00389; A61F2310/00592; A61F2310/00796
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
83 words
A stem assembly for an endoprosthesis to be anchored in a bone comprising a stem; means defining at least one expansible chamber (4) having a first wall sealed to said stem in a pressure-tight manner and a second wall at least partly enclosing said stem (1) and being expandable to contact an interior surface of said bone; a viscous liquid filler; and valve means for selectively introducing said filler into said chamber for expanding and substantially permanently pressurizing said chamber with hydrostatic pressure.
Claim 2
Dependent Claim
83 words
A stem assembly for an endoprosthesis to be anchored in a bone comprising a stem; means defining at least one expansible chamber (4) having a first wall sealed to said stem in a pressure-tight manner and a second wall at least partly enclosing said stem (1) and being expandable to contact an interior surface of said bone; a viscous liquid filler; and valve means for selectively introducing said filler into said chamber for expanding and substantially permanently pressurizing said chamber with hydrostatic pressure.
Claim 3
Dependent Claim
13 words
A stem assembly according to claim 1 wherein said filler is a fluid.
Claim 4
Dependent Claim
14 words
A stem according to claim 1 or 2 wherein said chamber (4) is periprosthetic.
Claim 5
Dependent Claim
23 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber includes a wall made of silicone.
Claim 6
Dependent Claim
25 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber includes a wall comprising braid impregnated with silicone.
Claim 7
Dependent Claim
29 words
A stem according to claim 5, wherein said braid includes two mutually crossing series of fibers (42) evincing a slope of about 45° relative to the stem axis (43).
Claim 8
Dependent Claim
26 words
A stem according to claim 6 wherein fibers of said braid are made of a material selected from the group consisting of carbon, polyester and polyamide.
Claim 9
Dependent Claim
28 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber includes a wall having a thickness of less than 0.5 mm.
Claim 10
Dependent Claim
44 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber includes a wall of said chamber (4) having more tensile strength in a proximal region (41) and in a distal region (7) than in a central region.
Claim 11
Dependent Claim
25 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber includes an outside surface coated with hydroxy-apatite particles.
Claim 12
Dependent Claim
19 words
A stem according to claim 1 wherein said valve means in said chamber (4) includes a one-way valve (9).
Claim 13
Dependent Claim
58 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber (4) includes means for affixing said at least one chamber to said prosthesis stem (1) such that said stem when implanted is capable of limited axial displacement relative to said bone and said chamber is axially immovable relative to said bone.
Claim 14
Dependent Claim
31 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber (4) includes, at least at the surface facing the bone (3), a biocompatible material.
Claim 15
Dependent Claim
34 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber (4) is formed, at least at the surface facing the bone (3), with a carbonaceous textured surface.
Claim 16
Dependent Claim
19 words
A stem according to claim 2 wherein said filler (16) comprises a liquid thickened with filler particles of carbon.
Claim 17
Dependent Claim
18 words
A stem assembly according to claim 8 wherein said wall has a thickness of less than 0.25 mm.
Claim 18
Dependent Claim
23 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber includes a wall made of polyurethane.
Claim 19
Dependent Claim
25 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber includes a wall comprising braid impregnated with polyurethane.
Claim 20
Dependent Claim
25 words
A stem according to claim 1 or 2 wherein said means defining said at least one chamber includes an outside surface coated with carbon particles.
Claim 21
Dependent Claim
25 words
A stem according to claim 1 wherein said chamber is expansible to occupy substantially all space in said cavity between said stem and said bone.
Claim 22
Dependent Claim
23 words
A stem according to claim 20 wherein said chamber is collapsed and is tightly against said stem during insertion and is subsequently expanded.
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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) | 1997-12-26 | 1998-06-27 | 1998-12-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-12-26 | 2002-06-27 | 2002-12-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-12-26 | 2006-06-27 | 2006-12-27 | $7700.00 | Window Closed / Lapsed |