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EP0432141A2
Expired / Lapsed
EP
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A femoral stem for permanent implantation into the natural femur
Assignee: Osteonics Biomaterials Inc
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Filing: 1985-03-29
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Granted: —
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Expires: 2005-03-29
Abstract
Abstract An orthopedic device (10), especially a hip joint prosthesis (10) comprising a stem and a spherical head, is formed from a composite material (42, 44) which is reinforced with continuous filament or carbon fibers (26) to provide the material with high flexural strength, hydrolytic stability and a medical grade quality. The stem and spherical head can be formed from a composite block (54). In the alternative, the stem alone can be formed from the block and a head of another material attached to one end of the stem. Sheets of carbon fibers held together by a polymer are rolled in a spiral configuration about an axial direction to form the stem and then molded under heat and pressure. The resulting composite is then machined to form the orthopedic device.
Inventors
- 👤 Robert D. Ainsworth
- 👤 Thirumalai N.C. Devanathan
- 👤 Steve T.C. Lin
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 21:36
CPC Classifications
A; A61; A61L; A61L27/00; A61L27/14; A61L27/18; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/3094; A61F2/30965; A61F2/32; A61F2/36; A61L27/40; A61L27/44; A61L27/443; A61F2002/30001; A61F2002/30003; A61F2002/30004; A61F2002/30009; A61F2250/00; A61F2250/0014; A61F2250/0028; Y; Y10; Y10S; Y10S623/00; Y10S623/901
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
157 words
A femoral stem (12) suitable for permanent human implantation into the natural femur, the femoral stem including an elongate shaft (14) extending in an axial direction and having a size and shape for implantation within the medullary canal of the natural femur, and a neck (16) unitary with the shaft and extending from the shaft at an angle to the axial direction of the shaft (14), the neck being suitable for replacement of the natural femoral neck, the angle laying in a plane to be aligned with the medial-lateral direction upon implant of the femoral stem, characterised in that the shaft and the neck are comprised of at least one sheet of continuous unidirectional filament carbon fibers embedded in a matrix of non-biodegradable, bio-compatible thermoplastic polymer and extending generally parallel to one another along an axis of orientation, the sheet being rolled upon itself into a spiral configuration about the axial direction to form the femoral stem.
Claim 2
Dependent Claim
22 words
A femoral stem in accordance with claim 1, wherein the axis of orientation of the fibers is parallel to the axial direction.
Claim 3
Dependent Claim
33 words
A femoral stem in accordance with claim 6, wherein the axis of orientation of the fibers is offset relative to the axial direction such that the fibers extend in a helical spiral configuration.
Claim 4
Dependent Claim
68 words
A femoral stem in accordance with claim 1 including a plurality of sheets of continuous unidirectional filament carbon fibers embedded in a matrix of non-biodegradable, bio-compatible thermoplastic polymer, the fibers of each sheet extending generally parallel to one another along an axis of orientation, the sheets being rolled (Figs. 16, 17, 18, 19) upon themselves into a spiral configuration about the axial direction to form the femoral stem.
Claim 5
Dependent Claim
29 words
A femoral stem in accordance with claim 4, wherein the axis of orientation of the fibers of at least one of the sheets is parallel to the axial direction.
Claim 6
Dependent Claim
41 words
A femoral stem in accordance with claim 1, wherein the axis of orientation of the fibers of at least one sheet is offset relative to the axial direction such that the fibers of that layer extend in a helical spiral configuration.
Claim 7
Independent Claim
86 words
A method of making an orthopedic device, in particular a femoral stem for a hip prosthesis in accordance with any one of the preceding claims, comprising: coating carbon fiber tow with a polymer to form a sheet of parallel carbon fibers held together by the polymer; cutting the sheet to form patterns of specific shape and fiber orientation; rolling the patterns into a cylinder; molding the rolled patterns under heat and pressure to form a dense composite; and machining the composite to form the orthopedic device.
Claim 8
Dependent Claim
34 words
A method as set forth in claim 7, wherein the polymer is selected from the group including polysulfone, polyethersulfone, Polyarylsulfone, polyphenylene sulfide, polycarbonates, aromatic polyamides, aromatic polyamideimides, thermoplastic polyimides, polyaryletherketone, polyetheretherketones, polyarylethernitriles, and polyhydroxyethers.
References Cited (Backward Citations)
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