EP0315283A2
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EP
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A method of shaping an endoprosthesis
Assignee: Orthopaedic Tech BV
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Filing: 1988-11-03
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Granted: —
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Expires: 2008-11-03
Abstract
Abstract A prosthesis having stresses acting on the interface between prosthesis and bone is designed by a computerized method in which the shape of the prosthesis is iteratively changed. A femoral head prosthesis is positioned in a bone by means of positioning elements, after which acrylic cement is inserted into the bone.
Inventors
- 👤 Johannes Franciscus Adrianus Maria Ypma
- 👤 Hendrik Willem Jan Huiskes
- 👤 Pierre Joseph Theodoor Marie Jaspers
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-23 14:03
CPC Classifications
A; A61; A61B; A61B17/00; A61B17/56; A61B17/58; A61B17/88; A61B17/8802; A61B17/8805; A61B17/8808; A61F; A61F2/00; A61F2/02; A61F2/30; A61F2/30721; A61F2/30723; A61F2/30724; A61F2/3094; A61F2/30942; A61F2/32; A61B17/8827; A61F2/30728; A61F2/36; A61F2/3662; A61F2/367; A61F2/3676; A61F2002/30001; A61F2002/30108; A61F2002/3011; A61F2002/30112; A61F2002/30113; A61F2002/30138; A61F2002/30182; A61F2002/30187; A61F2/30767; A61F2/30771; A61F2002/30795; A61F2002/30878; A61F2002/30891; A61F2002/30894; A61F2002/30955; A61F2/34; A61F2002/3401; A61F2002/3403; A61F2002/3412; A61F2002/3414; A61F2002/3443; A61F2/3609; A61F2002/3625; A61F2002/3678; A61F2002/3686; A61F2002/3688; A61F2/46; A61F2002/4631; A61F2230/00; A61F2230/0002; A61F2230/0004; A61F2230/0006; A61F2230/0017; A61F2230/0028; A61F2230/0034; Y; Y10; Y10S; Y10S623/00; Y10S623/901; Y10S623/909; Y10S623/911
Claims Analysis
Total Claims: 29
Claim 1
Independent Claim
90 words
A method of shaping a prosthesis to be fixed in a bone, comprising the following steps: - presetting a desired pattern of stresses between bone and prosthesis; - providing material properties of bone and prosthesis; - setting one or more external load conditions; - calculating the stress pattern between bone and prosthesis for a chosen initial shape of the prosthesis; and - iteratively changing the shape of the prosthesis, such that differences between the calculated stresses of successive shapes of prostheses and the desired pattern stresses reach a predetermined value.
Claim 2
Independent Claim
90 words
A method of shaping a prosthesis to be fixed in a bone, comprising the following steps: - presetting a desired pattern of stresses between bone and prosthesis; - providing material properties of bone and prosthesis; - setting one or more external load conditions; - calculating the stress pattern between bone and prosthesis for a chosen initial shape of the prosthesis; and - iteratively changing the shape of the prosthesis, such that differences between the calculated stresses of successive shapes of prostheses and the desired pattern stresses reach a predetermined value.
Claim 3
Dependent Claim
40 words
A method according to claim 1, in the model of which cement mantel and its material properties are included and in which the strain energy density acting inside the cement mantel is changed until its value reaches a predetermined value.
Claim 4
Dependent Claim
19 words
A method according to claim 1, in which normal and sheer stresses acting between prosthesis and bone are minimized.
Claim 5
Dependent Claim
31 words
A method according to claim 1, in which the nodal points from the iteratively derived shape of the prosthesis are interpolated, in order to obtain a smooth contour of the prosthesis.
Claim 6
Dependent Claim
29 words
A prosthesis having such a shape, that after having been inserted into a bone, stresses at contact surfaces have values which are as low and evenly distributed as possible.
Claim 7
Dependent Claim
29 words
A prosthesis having such a shape, that after having been inserted into a bone, stresses at contact surfaces have values which are as low and evenly distributed as possible.
Claim 8
Dependent Claim
20 words
A femoral head prosthesis of which the stem has a belly at a proximal medial side below the resection plane.
Claim 9
Dependent Claim
20 words
A femoral head prosthesis of which the stem has a belly at a proximal medial side below the resection plane.
Claim 10
Dependent Claim
15 words
A femoral head prosthesis according to claim 6, showing a taper of the proximal stem.
Claim 11
Dependent Claim
15 words
A femoral head prosthesis according to claim 6, having a taper of the distal stem.
Claim 12
Dependent Claim
21 words
A femoral head prosthesis according to claims 7 and 8, of which the distal taper is slimmer than the proximal taper.
Claim 13
Dependent Claim
32 words
A femoral head prosthesis according to one of the claims 5-9, having such a shape that after insertion in the femoral bone the stem tip is located medially of the intra-medullary axis.
Claim 14
Dependent Claim
20 words
A femoral head prosthesis according to one of the claims 5-9, having a shape curved relative to the intramedullary axis.
Claim 15
Independent Claim
39 words
A method for positioning an endoprosthesis in a bone and for the fixation of this bone with acrylic cement, in which the endoprosthesis is, preferably only once, positioned into the bone previous to the insertion of the acrylic cement.
Claim 16
Independent Claim
39 words
A method for positioning an endoprosthesis in a bone and for the fixation of this bone with acrylic cement, in which the endoprosthesis is, preferably only once, positioned into the bone previous to the insertion of the acrylic cement.
Claim 17
Dependent Claim
21 words
A method according to claim 12, in which a stem tip positioning element and a proximal stem positioning element are provided.
Claim 18
Dependent Claim
25 words
A positioning element or spacer fitting over the neck of a femoral head prosthesis and to be positioned at the level of the resection plane.
Claim 19
Dependent Claim
25 words
A positioning element or spacer fitting over the neck of a femoral head prosthesis and to be positioned at the level of the resection plane.
Claim 20
Dependent Claim
18 words
A positioning element or spacer according to claim 14 provided with a hole for an air venting tube.
Claim 21
Dependent Claim
20 words
A positioning element or spacer according to claim 14 or 15 provided with a hole for injection of acrylic cement.
Claim 22
Dependent Claim
15 words
An acetabular prosthesis provided with an insert for the joint surface and a metal backing.
Claim 23
Dependent Claim
15 words
An acetabular prosthesis provided with an insert for the joint surface and a metal backing.
Claim 24
Dependent Claim
16 words
An acetabular prosthesis according to claim 17 of which the metal backing has a varying thickness.
Claim 25
Dependent Claim
24 words
An acetabular prosthesis according to claims 17 or 18 of which the metal backing proceeds at the lateral superior side unto the acetabuler plane.
Claim 26
Dependent Claim
27 words
An acetabular prosthesis according to 17, 18 or 19, of which the metal backing at the medial inferior side continues unto the acetabularplane as far as possible.
Claim 27
Dependent Claim
27 words
An acetabular prosthesis according to 17, 18 or 19, of which the metal backing at the medial inferior side continues unto the acetabularplane as far as possible.
Claim 28
Dependent Claim
27 words
An acetabular prosthesis according to claims 18, 18, 19 or 20 of which the metal backing is equal or less than 1 mm thick at the periphery.
Claim 29
Dependent Claim
30 words
An acetabular prosthesis according to claims 17, 18, 19, 20 or 21 of which the metal backing is thicker at its central dome or its near surroundings than the periphery.
References Cited (Backward Citations)
No citation records indexed.
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