U.S. patent number RE38,058 [Application Number 08/582,025] was granted by the patent office on 2003-04-01 for mill and guide apparatus for preparation of a hip prosthesis.
This patent grant is currently assigned to Smith & Nephew, Inc.. Invention is credited to Thomas W. Fallin.
United States Patent |
RE38,058 |
Fallin |
April 1, 2003 |
Mill and guide apparatus for preparation of a hip prosthesis
Abstract
A guide apparatus for preparing the femur of a patient with a
rotary mill to receive a femoral hip prosthesis includes a V-shaped
guide body having a lower end base portion adapted to extend into
the intermedullary canal of the femur and an upper end portion
comprised of at least two spaced apart struts so that the overall
guide body had a configuration substantially the same as the
prosthesis body sought to be implanted in the patient. The lower
end of the guide body base provides one or more hemispherical
receptacles for holding the hemispherical end portion of a spinning
mill bit. A preferably removable transverse guide rail has
connection pins at one end portion thereof for forming a connection
with the upper end of the guide body at one of the struts, the arm
having a curved surface that is adapted to guide the mill bit
during preparation of the intermedullary canal of the patient's
femur for receiving a hip prosthesis thereafter.
Inventors: |
Fallin; Thomas W. (Hyde Park,
UT) |
Assignee: |
Smith & Nephew, Inc.
(Memphis, TN)
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Family
ID: |
27382421 |
Appl.
No.: |
08/582,025 |
Filed: |
January 2, 1996 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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120034 |
Sep 10, 1993 |
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308205 |
Feb 8, 1989 |
4995883 |
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Reissue of: |
476172 |
Feb 7, 1990 |
05047033 |
Sep 10, 1991 |
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Current U.S.
Class: |
606/87 |
Current CPC
Class: |
A61B
17/175 (20130101) |
Current International
Class: |
A61B
17/17 (20060101); A61B 17/16 (20060101); A61F
005/04 () |
Field of
Search: |
;606/79,80,84,85,86,87
;632/22.11,22.12,22.4 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Isabella; David J.
Attorney, Agent or Firm: Pravel, Hewitt, Kimball &
Krieger
Parent Case Text
CROSS REFERENCE TO RELATED APPLICATIONS
.Iadd.This is a continuation of application Ser. No. 08/120,034,
filed on Sep. 10, 1993 .Iaddend..[.This.]. .Iadd.which .Iaddend.is
a continuation-in-part of U.S. patent application Ser. No.
07/308,205, filed 02/08/89 now U.S. Pat. No. 4,995,883.
Claims
What is claimed as invention is:
1. A guide apparatus for preparing the femur of a patient with a
mill to receive a femoral hip prosthesis comprising: a) a guide
body having a lower end base.Iadd., the guide body being
connectable to .Iaddend..[.adapted to extend into the
intermedullary canal of the.]. .Iadd.a patient's .Iaddend.femur
.Iadd.during use.Iaddend., and .Iadd.having .Iaddend.an upper end
portion comprised of at least one strut; b) the .[.lower end of the
base having.]. .Iadd.guide body including .Iaddend.receptacle means
for holding .[.one end of.]. a spinning mill; c) .[.a.]. .Iadd.at
least a partially .Iaddend.curved transverse guide rail having
connection means thereon for forming a connection with the upper
end of the guide body, the rail having .[.a.]. .Iadd.at least a
partially .Iaddend.curved surface that is adapted to guide the mill
during preparation of the .[.intermedullary.]. .Iadd.intramedullary
.Iaddend.canal of the patient's femur for receiving a hip
prosthesis.
2. The apparatus of claim 1 wherein the guide body comprises a base
with a pair of struts extending upwardly therefrom.
3. The apparatus of claim 2 further comprising a receptacle formed
on the upper end portion of the guide body for receiving the
connection means portion of the guide rail.
4. The apparatus of claim 1 wherein the connection forming means
comprises a reversible connector that attached the guide rail to
the guide body in multiple positions.
5. The apparatus of claim 1 wherein the guide body is V-shaped and
includes medial and lateral spaced apart struts.
6. The apparatus of claim 5 wherein the connection means forms a
connection with the medial strut.
7. The apparatus of claim 5 wherein the connection means comprises
a receptacle carried by one of the struts of the V-shaped body, and
a pair of opposed pegs carried by one end portion of the guide rail
for respectively attaching the guide rail to the guide body and
pre-selected left and right respective positions so that the guide
rail can be used to form posterior and anterior sides of the
.[.intermedullary.]. .Iadd.intramedullary .Iaddend.canal.
8. The apparatus of claim 5 wherein the V-shaped guide body
includes a pair of spaced apart struts including a generally
vertically upstanding strut and inclined strut forming an acute
angle therewith.
9. The apparatus of claim 5 wherein the guide body defines an
envelope having a shape corresponding to the shape of an upper end
portion of the prosthesis body to be placed in the patient's
femur.
10. The apparatus of claim 1 wherein the receptacle means includes
a pair of spaced apart, anterior and posterior receptacles each
being sized to receive the lower end portion of the mill.
11. The apparatus of claim 1 wherein the guide body defines an
envelope having substantially the same configuration as the
prosthesis body sought to be implanted in the patient.
12. The apparatus of claim 1 wherein the guide rail includes a
curved arm portion having a bearing surface thereon which allows
the mill to track .[.and.]. .Iadd.an .Iaddend.arcuate path
extending generally away from the central axis of the
.[.intermedullary.]. .Iadd.intramedullary .Iaddend.canal so that
the mill forms a cut in the .[.intermedullary.].
.Iadd.intramedullary .Iaddend.canal that increases the size of the
.[.intermedullary.]. .Iadd.intramedullary .Iaddend.canal from the
distal end portion thereof to the proximal end portion thereof.
13. The apparatus of claim 1 wherein the guide rail includes a
cantilevered arm portion extending away from the connection means,
the cantilevered arm carrying a curved guide surface that is
positioned to engage the mid-section of the mill during use.
14. A guide apparatus for preparing the femur with a mill to
receive a hip prosthesis comprising: a) a V-shaped guide body
having substantially the same configuration as a corresponding hip
prosthesis to be implanted, said guide body including a lower end
base configured to extend at least partially into the
.[.intermedullary.]. .Iadd.intramedullary .Iaddend.canal of the
femur, and an upper end portion comprised of a pair of spaced apart
struts forming a V-shaped configuration; b) an elongated mill
having a lower end portion with a hemispherical tip thereon and
circumferentially spaced apart cutter blades extending between the
hemispherical tip and at least a mid-section of the mill, and an
upper end portion of the mill having a tooled end portion to
receive a rotary drill for rotating the bit; c) the lower end of
the base having receptacle means for holding the end of a spinning
mill bit; d) a curved guide rail having connection means thereon
for forming a connection with one of said struts, said guide rail
having an arm extending substantially transverse to said struts,
said arm having a curved surface that is adapted to guide the
reamer bit .[.during.]. therealong as the hemispherical tip pivots
in said receptacle means thereby preparing the .[.intermedullary.].
.Iadd.intramedullary .Iaddend.canal for receipt of the hip
prosthesis. .Iadd.
15. A guide apparatus for preparing the femur of a patient with a
mill to receive a femoral hip prosthesis, comprising: a) a guide
body having an upper end portion and a lower end portion, the guide
body being connectable to a patient's femur, forming a connection
therewith during use; b) the guide body including means for holding
a spinning mill during a cutting of the patient's femur at the
intramedullary canal of the femur; c) an at least partially curved
guide rail portion that extends generally transversely with respect
to the mill, the rail having means for forming a connection with
the upper end portion of the guide body, the rail having a surface
that is adapted to guide the mill during preparation of the
intramedullary canal of the patient's femur for receiving a hip
prosthesis..Iaddend..Iadd.
16. A method of for preparing the femur of a patient with a mill to
receive a femoral hip prosthesis, comprising the steps of: a)
attaching a guide body having an upper end portion and a lower end
portion to the patient's femur, forming a connection therewith; b)
supporting a spinning mill upon the guide body during a cutting of
the patient's femur at the intramedullary canal of the patient's
femur; c) cutting the patient's bone tissue at the intramedullary
canal using the spinning mill; d) guiding transverse movement of
the spinning mill during cutting of the patient's bone tissue at
the intramedullary canal of the patient's femur with a guide rail
portion that extends generally transversely with respect to the
mill, the rail being connected during use to the guide body, the
rail having a surface that is adapted to guide the mill during
preparation of the intramedullary canal of the patient's femur for
receiving a hip prosthesis..Iaddend..Iadd.
17. The method of claim 16 wherein the rail is removably attachable
to the guide body..Iaddend..Iadd.
18. The method of claim 17 wherein in step "a" the lower end of the
guide body is attached to the patient's femur..Iaddend..Iadd.
19. The method of claim 16 wherein in step "b" the mill extends
partially into the patient's femur during cutting
thereof..Iaddend..Iadd.
20. The method of claim 16 wherein the rail prevents excess cutting
of bone tissue by the mill by limiting transverse movement of the
mill..Iaddend..Iadd.
21. The method of claim 16, wherein the mill is generally aligned
with the central longitudinal axis of the patient's intramedullary
canal..Iaddend.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a modular hip prosthesis system
wherein various custom, selected component parts of an implant can
be selected during the surgical procedure and a corresponding mill
or rotary reamer guide selected to prepare the femur so that the
implant can be custom fitted to a patient.
2. General Background
Increasingly, surgeons want to be able to custom fit femoral
prostheses to patients. Instead of having to choose a properly
sized prosthesis from a group of pre-formed implants, it would be
advantageous to have a basic design which can be modified with
various component parts. This would eliminate the need to maintain
a large inventory and would provide better fitting implants. In
addition, the femur of each patient can differ slightly so that
some cutting and/or reaming of the intermedullary cavity is
desireable for properly preparing the femur to receive the selected
prosthesis.
Custom fitted implants are particularly important in revision cases
where an implant has to be removed and replaced since old cement
must be removed and bone resorption occurs in many cases.
Unpredictable, proximal and/or distal bone loss of deformity often
occurs which must be accommodated by the replacement
prosthesis.
For initial implants, basic variations in patient anatomy are often
confronted by the surgeon. Variations in intramedullary canal
diameter can also occur, which if not accompanied by a properly
sized implant, can result in distal toggle.
In short, it is difficult, of not impossible, to predict the exact
shape of a hip implant which is suitable for all patients. Since it
is impractical and would be prohibitively expensive to maintain an
inventory of implants for most patients, compromises must sometimes
be made in supplying implants which fit reasonably well but could
be improved upon.
Several hip prostheses are known which are formed of replaceable or
interchangeable component parts.
U.S. Pat. No. 3,641,590 entitled "Acetabular Replacement Prosthesis
and Method of Assembling" issued to Michele discloses a selective
individualized technique for acetabulum socket replacement per se,
or in conjunction with a hip replacement prosthesis (referring to
the Michele U.S. Pat. No. 3,228,393) for a total hip replacement,
designed for all ages including the very young. A selective
anchorage for a cup prosthesis of a size selected from the limited
number of differently sized cups is made available. Anchorage of
the acetabular socket replacement conforms to variations in
dimensions, shapes and positions of the (medullary) canals of the
acetabulum pelvis of the individual patient and includes at least
two elongated and convergent or divergent fasteners.
A removable collar of low modular of elasticity material is shown
in U.S. Pat. No. 4,012,796 entitled "Interpositioning Collar For
Prosthetic Bone Insert" issued to Weisman et al. The collar is
interpositioned between a collar of a metal prosthetic hip stem
implanted in the intramedullary canal of the femur and the adjacent
calcar or outer edge of the bone. A flange depends from the insert
between the upper portion of the stem and the inner wall of the
bone. The interpositioned collar is either a full elongated tapered
O-shape or it is open on one side of a tapered U-shape.
U.S. Pat. No. 4,404,691 entitled "Modular Prosthesis Assembly"
issued to Buning et al., provides a modular hip prosthesis assembly
for replacement of at least part of a joint and part of a bone
shaft including a mounting component provided with a connection
portion and at least two joint components of similar shape but
different dimensions and which can be connected alternatively to
the mounting component, each of the joint components having an
engagement portion and a connection part adapted for connection to
the connection portion of the mounting component, the joint
components each providing part of a bone shaft and part of a joint
which can cooperate with an appropriate part of a natural or
artificial joint.
U.S. Pat. No. 4,578,081 entitled "Bone Prosthesis" issued to Harder
et al., discloses a bone prosthesis comprising at least one joint
component replacing a natural joint half, which is provided with a
shank adapted to be connected to the bone, wherein a set of joint
components is provided, and the shank is designed as a bone
replacement member, with a connection portion provided adapted to
be connected to the bone at one end and at the other end to the
shank. One of the components is a hip prosthesis with a rounded
head and a hollowed hip component that connects to elongated
mounting components. In another hip prosthesis embodiment, a neck
with a cone shape receives a suitable joint head with an inner
cone.
A femoral component for hip prosthesis is shown in U.S. Pat. No.
4,608,055 issued to Morrey et al., the prosthesis disclosed in the
'055 patent includes a stem portion and a combined integral head
and neck portion. The stem portion includes a proximal portion and
a distal portion which are angular related with a respect to one
another and with the proximal portion including a recess formed
therein for receipt of a tapered portion of the head and neck
component. The head and neck component includes a substantially
part spherical head portion attached to a neck portion and a
tapered portion angularly attached to the neck portion via a
basilar neck portion with the tapered portion being adapted to be
permanently inserted into the recess portion of the proximal end of
the above described stem portion. The stem portion includes a
plurality of recesses on the periphery and longitudinal extent
thereof for receiving fiber metal pads which are provided to allow
boney ingrowth therein in order to retain the femoral component
permanently installed in the proximal end of the femur.
In U.S. Pat. No. 4,676,797 entitled "Unit for Resection
Prosthesis", a resection prosthesis assembly unit includes a head
member, an end member and an intermediate member between the head
and end members, of which one member is provided with a conical pin
and another member is provided with a conical pin and another
member is provided with a conical bore. The latter two members are
provided with respective first surfaces extends transversely to an
insertion direction and which face one another and are spaced apart
to define a recess when the two members are connected together. One
of the two members is further provided with a second surface
extending in the insertion direction, and the recess being provided
to receive a wedge insertable into the recess to bear against the
first surfaces for forcing the two members apart while the forces
exerted by the wedge are absorbed by the first surfaces and the
wedge is guided by the second surface.
One type of cutting guide for use with a reamer in preparing the
proximal end of the femur for a hip prosthesis is described in U.S.
Pat. No. 4,777,942, entitled "Bone Milling Instrument." The '942
patent discloses a milling instrument which is inserted into a
medullary cavity and a spindle which is linked to the caliper at an
angle. The spindle carries a milling cutter as well as a guide shoe
at the distal end which slides within a guideway at the distal end
of the caliper. The instrument is able to cut a circular arc
corresponding to the boundary line between the spongiosa and
cortical tissue in the region of the calcar arc.
SUMMARY OF THE INVENTION
The present invention provides a rotary reamer guide apparatus for
preparing the femur for a hip prosthesis which can then be custom
fitted to a particular patient by a surgeon prior to surgical
insertion of the prosthesis.
The apparatus includes preferably a V-shaped guide body having a
lower end base portion that is adapted to extend into the
intermedullary canal of the femur during use, with an upper end
portion comprised of a pair of spaced apart struts. The lower end
of the base includes one or more receptacles for holding the end of
a mill or rotary reamer.
In the preferred embodiment, the mill provides at its lower end
portion a hemispherical surface and the receptacle comprises a pair
of spaced apart hemispherical receptacles, for containing the
hemispherical portion of the mill in one of two pre-selected
cutting positions for the lower end of the reamer.
A curved, transverse guide rail is provided which attaches at a
removable connection with the upper end of the guide body at one of
the struts, the guide rail including a cantilevered arm having a
curved surface that is adapted to engage and guide the mill during
preparation of the intermedullary canal of the patient's femur
before receiving a hip prosthesis.
Because the guide rail is removable from the guide body, the
present invention provides a modular kit wherein a plurality of
different guide rails can be used for creating cuts of different
pre-selected configurations in the intermedullary canal. Thus, the
surgeon can select a particular guide rail configuration and
resultant cut for the intermedullary canal depending upon the
particular patient's needs and depending upon a particular selected
modular prosthesis that will be implanted.
The guide body preferably defines an envelope having a size and
shape that corresponds to the shape of the upper end portion of the
prosthesis body so that the guide body and the cut made by the
reamer closely corresponds to the actual shape of the prosthesis to
be implanted, thus eliminating the problem of a poor fit.
In the preferred embodiment, the guide rail provides a cantilevered
arm that extends away from the V-shaped guide body, connecting
thereto by means of a removable connection, such as, for example, a
pair of spaced apart pins that downwardly extends from the
cantilevered arm into sockets provided on the guide body. As an
alternate construction, the connection can be in the form of a
dove-tail shaped connection member carried by the guide rail, arm
and slidably interfacing with a dove-tail shaped recess in the
guide body. The guide rail can provide connectors on both the
superior and inferior surfaces to that each guide rail can be used
to make both anterior and posterior cuts as desired.
BRIEF DESCRIPTION OF THE DRAWINGS:
For a further understanding of the nature and objects of the
present invention, reference should be had to the following
detailed description, taken in conjunction with the accompanying
drawings, in which like parts are given like reference numerals,
and wherein:
FIG. 1 is a perspective view of the preferred embodiment of the
apparatus of the present invention;
FIG. 2 is a fragmentary side view of the preferred embodiment of
the apparatus of the present invention illustrating the guide
body;
FIG. 3 is a sectional view taken along lines 3--3 of FIG. 2;
FIG. 4 is a top view of the guide body of FIG. 2;
FIG. 5 is a fragmentary view of the preferred embodiment of the
apparatus of the present invention illustrating the mill portion
thereof;
FIG. 6 is another fragmentary view of the mill portion of the
apparatus of the present invention;
FIG. 7 is a side view of the mill portion of the apparatus of the
present invention;
FIG. 8 is a top view of the preferred embodiment of the apparatus
of the present invention, shown in position in a patient's femur
with the mill being shown in hard and in phantom lines in multiple
cutting positions;
FIG. 9 is a top view of the preferred embodiment of the apparatus
of the present invention illustrating a second construction of the
guide rail;
FIG. 10 is a side view of the preferred embodiment of the apparatus
of the present invention showing a second construction of the guide
rail;
FIG. 11 is a sectional view taken along lines 11--11 of FIG. 9;
FIG. 12 is a sectional view taken along lines 12--12 of FIG. 9;
and
FIG. 13 is a fragmentary side view of the second construction of
the guide rail connection for the embodiment of FIGS. 9-12.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1 and 8 show generally the preferred embodiment of the
apparatus of the present invention designated generally by the
numeral 10. Mill apparatus 10 includes a mill 11 having a base 12
portion at its lower end and a pair of spaced apart struts 13, 14
extending upwardly therefrom. The guide body 11 has a lower
receptacle in the form of a pair of spaced apart hemispherical
bearing cups 15, 16 each of which carries a corresponding
hemispherical end portion 21 of reamer 20 (see FIGS. 1, 7, and 8)
during use. The guide body has an overall shape and configuration,
as shown in FIGS. 2 and 4, that corresponds to the shape of the
upper end portion of a hip prosthesis to be implanted, so that the
strut 13 defines a medial strut and the strut 14 defines a lateral
strut.
The surgeon prepares the intermedullary canal with a broach, for
example, which is generally shaped to the configuration of the
prosthesis body to be implanted in the intermedullary canal. The
broach (not shown) typically has an envelope that corresponds to
the envelope of the prosthesis body to be implanted. After the
surgeon prepares the intermedullary canal using the broach, the
guide body 11 is inserted into the intermedullary canal and a
particular guide rail 30 selected by the surgeon depending upon the
shape of the desired cut to be made by the mill, and as selected by
the surgeon. It is possible that cutting on one side of the guide
body only would be desired, and thus the surgeon may only use the
mill to cut on one side, as shown in FIG. 1.
The arm 31 would preferably be reversible in order to cut on both
medial and lateral sides of the intermedullary canal. In that
respect, the guide rail 30 would preferably be removable from the
guide body 11, and reversible, having pairs of attachment pins 31,
32 on both its upper and its lower surfaces. Pin openings 17, 18 in
guide body receive corresponding pins 31, 32 of guide rail to form
the connection. In FIG. 1, the lower surface set of pins 31, 32 is
not shown because the lower set of pins are in the openings 17,
18.
In the embodiment of FIGS. 9--13, a dove-tail connector 34 would be
provided on each side of guide arm 30 for connecting with a
corresponding dove-tailed groove 39 milled in the top of the strut
13, so that the guide rail 30 has the same generally horizontal
orientation as with the preferred construction of FIG. 1. Thus,
when connector 34 registers in groove 39, the rail 30 can be
extended either rearwardly of guide body 11 for posterior cuts and
forwardly of guide body 11 for anterior cuts. Stop pins 38 limit
the movement of guide rail 30 with respect to body 11 during
milling or cutting using mill.
Once attached, the guide rail 30 provides a generally curved guide
surface 35 that extends between the connection end portion 40 of
guide rail 30 to the free end 37 portion thereof. The shape of
guide surface 35 would vary, depending upon the size of the cut to
be made by the mill 20 as selected by the surgeon. Thus, a
plurality of guide rails 30 could be provided in kit form to the
surgeon, each with a different curvature or configuration of
surface 35.
The surface 35 would be a abutted during operation with bearing
sleeve 22 of mill 20, as shown in FIG. 1. The sleeve 22 could be
removably attached to the central portion 23 of mill 20 which could
be in the form of a reduced diameter section 25 of mill 20 as shown
in FIG. 7.
The upper end portion 28 of mill 20 has a tool receptive tip having
multiple flat surfaces 27 which are circumferentially spaced (see
FIG. 6) so that a drill or the like could be attached to drive mill
20. A plurality of circumferentially spaced apart blades 24 would
be provided on the lower end of mill 20 for the purposes of cutting
away bone tissue during use.
Because many varying and different embodiments may be made within
the scope of the inventive concept herein taught, and because many
modifications may be made in the embodiments herein detailed in
accordance with the descriptive requirement of the low, it is to be
understood that the details herein are to be interpreted as
illustrative and not in a limiting sense.
* * * * *