U.S. patent application number 09/826500 was filed with the patent office on 2001-08-23 for milling tool for emptying the femoral medullary space and hip prosthesis to be inserted in the space created.
Invention is credited to Lubinus, Philipp.
Application Number | 20010016779 09/826500 |
Document ID | / |
Family ID | 7823949 |
Filed Date | 2001-08-23 |
United States Patent
Application |
20010016779 |
Kind Code |
A1 |
Lubinus, Philipp |
August 23, 2001 |
Milling tool for emptying the femoral medullary space and hip
prosthesis to be inserted in the space created
Abstract
Milling tool for emptying the femoral medullary space, whilst
creating a space for the shaft of a hip prosthesis, which comprises
a flexible core and a plurality of conical, rotationally
symmetrical milling segments, mounted in superimposed manner on the
core and provided with a central through-bore, the milling segments
being so connected to the core and/or the milling segments adjacent
thereto, that a rotational force applied to the core and/or the
upper segment is transferred to the individual milling segments, as
well as a hip prosthesis with a conically directed shaft and a ball
mounted on the proximal end of the shaft and which comprises a
flexible core, a plurality of conical, rotationally symmetrically
segments, mounted in superimposed manner on the core and provided
with a central through-bore and a device for tensioning the core to
bring a stiffening of the shaft formed from the individual
segments.
Inventors: |
Lubinus, Philipp; (Kiel,
DE) |
Correspondence
Address: |
M. Robert Kestenbaum
11011 Bermuda Dunes NE
Albuquerque
NM
87111
US
|
Family ID: |
7823949 |
Appl. No.: |
09/826500 |
Filed: |
April 4, 2001 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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09826500 |
Apr 4, 2001 |
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09381486 |
Sep 20, 1999 |
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09381486 |
Sep 20, 1999 |
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PCT/DE98/00763 |
Mar 14, 1998 |
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Current U.S.
Class: |
623/23.18 |
Current CPC
Class: |
A61F 2220/0025 20130101;
A61F 2002/3021 20130101; A61F 2002/365 20130101; A61B 17/175
20130101; A61F 2002/3694 20130101; A61F 2/3662 20130101; A61F
2230/0067 20130101; A61B 17/1668 20130101; A61F 2002/30599
20130101; A61F 2220/0033 20130101; A61F 2250/0063 20130101; A61F
2002/30329 20130101; A61B 17/164 20130101; A61F 2002/30354
20130101; A61F 2002/30217 20130101; A61F 2002/30507 20130101; A61F
2002/3611 20130101 |
Class at
Publication: |
623/23.18 |
International
Class: |
A61F 002/36 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 20, 1997 |
DE |
197 11 532.2 |
Claims
1. Hip prosthesis having a conically directed shaft and a ball (16)
mounted on the proximal end of the shaft, characterized in that the
hip prosthesis comprises a flexible core (10), a plurality of
conical, rotationally symmetrical segments (12), mounted in
superimposed manner on the core (10) and provided with a central
through-bore and a device (14) for tensioning the core (10)
bringing about a stiffening of the shaft formed from the individual
segments (12).
2. Hip prosthesis according to claim 1, characterized in that the
central through-bore has a wasp waist cross-section.
3. Hip prosthesis according to claim 1, characterized in that the
distally positioned segment (12) is firmly attached to the core
(10).
4. Hip prosthesis according to claim 1, characterized in that the
end faces of the segments (12) are slightly convex.
Description
[0001] This is a Divisional Application of patent application Ser.
No. 09/381,486 filed Sep. 20, 1999 of the same invention.
CROSS-REFERENCES TO RELATED APPLICATIONS
[0002] Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OF DEVELOPMENT
[0003] Not applicable.
BACKGROUND OF THE INVENTION
[0004] 1. Technical Field
[0005] This invention relates to a milling tool for emptying the
femoral medullary space, whilst creating a space for the shaft or
shank of a hip prosthesis and a hip prosthesis suitable for
insertion in said space.
[0006] The insertion of a hip prosthesis comprising a shaft and a
ball to be attached at an angle thereto is a frequent, regularly
relatively uncomplicated surgical operation.
[0007] However, difficulties arise in those cases in which the
femoral medullary space to be emptied with the aid of a milling
tool prior to the insertion of the hip prosthesis shaft is not
straight, but instead curved, because then when using the
conventional, straight milling tools regularly and in undesired
manner bony substance to be maintained is also milled off.
[0008] 2. Background Art
[0009] DE 29 14 455 discloses a device for producing a cavity in a
bone for the insertion of an artificial joint part, in which two
rasp halves adapted to the shape of the bone cavity to be produced
are placed on a flexible turning tool drive shaft, the two rasp
halves being movable against one another in the axial
direction.
[0010] WO 94/27507 discloses a milling tool for emptying the
femoral medullary space, whilst creating a space for the shaft of a
hip prosthesis, having a flexible core and a plurality of conical,
rotationally symmetrical milling segments, mounted in superimposed
manner on the core and provided with central through-bores, which
transfer or transmit a rotational force applied to the core. The
pins provided therein for transferring the rotational force shear
off, however, on bending the core in non-straight femoral medullary
spaces.
SUMMARY OF THE INVENTION
[0011] The problem of the invention is to provide a milling tool
making it possible to create a space for a hip prosthesis shaft
following the path of the femoral medullary space, as well as a hip
prosthesis, which can be inserted in such a non-straight, emptied
femoral medullary space.
[0012] According to the invention this problem is solved by a
milling tool for emptying the femoral medullary space, whilst
creating a space for the shaft of a hip prosthesis, having a
flexible core and a plurality of conical, rotationally symmetrical
milling segments, mounted in superimposed manner on the core and
provided with central through-bores, which transmit a rotational
force applied to the core, and a device for tensioning the core.
According to the invention the above-stated problem is also solved
by having a hip prosthesis having a conically directed shaft and a
ball mounted on the proximal end of the shaft, wherein the hip
prosthesis comprises a flexible core, a plurality of conical,
rotationally symmetrical segments, mounted in superimposed manner
on the core and provided with a central through-bore and a device
for tensioning the core bringing about a stiffening of the shaft
formed from the individual segments.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The invention is described in greater detail hereinafter
relative to the drawings, wherein:
[0014] FIG. 1 is diagrammatic representation of such a milling tool
in an untensioned core.
[0015] FIG. 2 is representation corresponding to FIG. 1 for a
tensioned core.
[0016] FIG. 3 is hip prosthesis with an untensioned core.
[0017] FIG. 4 is representation corresponding to FIG. 3 for a
tensioned core.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The milling tool shown in FIGS. 1 and 2 comprises a flexible
core and a plurality of conical, rotationally symmetrical milling
segments provided with a not shown, central through-bore and
mounted in superimposed manner on the core 10.
[0019] The core is cross-sectionally noncircular and the
through-bore of the milling segments 12 is provided with a
correspondingly noncircular, axially directed through-bore
(additively or alternatively the end faces of the individual
milling segments 12 pointing towards one another can also be
provided with meshing radial serrations).
[0020] The core is provided with a tensioning device 14 acting on
the upper milling segment 12 and whose tightening tensions the core
10 against the upper milling segment 12 and consequently beings
about a mutual stiffening of the milling segments 12 (and
consequently the shaft formed from the individual milling segments
12).
[0021] The drawing also shows that the end faces of the milling
segments pointing towards one another are slightly convex, so that
they can roll on one another.
[0022] The lowermost milling segment 12 is firmly attached to the
core 10.
[0023] For emptying the femoral medullary space the milling tool is
attached in the conventional manner with the core 10 untensioned.
The distal milling segment 12 (the tip firmly connected to the core
10) will follow the path of the relatively soft femoral medullary
space and the following milling segments follow this pate. During
the rotation of the milling tool resulting from the application of
a rotational force to the core and/or the upper milling segment,
they mainly only empty the soft material of the femoral medullary
space, thereby protecting the bone. Thus, the milling tool
"meanders" through the curved femoral medullary space and empties
the same whilst protecting the bone material.
[0024] The hip prosthesis shown in FIGS. 3 and 4 has a
corresponding construction. It comprises a flexible core 10, a
plurality of conical, rotationally symmetrical segments, mounted in
superimposed manner on the core 10 and provided with a central
through-bore and a device 14 for tensioning the core 10 bringing
about the stiffening of the shaft formed from the individual
segments 12.
[0025] In the state shown in FIG. 3 in which the core 10 is not
tensioned, the hip prosthesis shaft is driven into the previously
emptied (not strictly linearly directed) femoral medullary space.
During this process the individual segments 12 are so oriented
(i.e. tilt with respect to the imaginary shaft axis), that the
shaft is adapted to the femoral medullary space.
[0026] Following the driving in of the shaft core 10 is tensioned,
so that the shaft is stiffened and loaded in the direction of an
increasing straightening, which, due to the elasticity of the bone
material, leads to a large-area engagement of the segments forming
the shaft on the retained bony substance and consequently permits a
much greater force transfer of the prosthesis shaft to the femur
than would be possible when using a straight shaft.
* * * * *