U.S. patent application number 14/100367 was filed with the patent office on 2014-04-03 for expandable proximal reamer.
The applicant listed for this patent is JONATHAN E. CARR, LARRY G. MCCLEARY, SAMUEL G. SACKETT. Invention is credited to JONATHAN E. CARR, LARRY G. MCCLEARY, SAMUEL G. SACKETT.
Application Number | 20140094810 14/100367 |
Document ID | / |
Family ID | 39591235 |
Filed Date | 2014-04-03 |
United States Patent
Application |
20140094810 |
Kind Code |
A1 |
SACKETT; SAMUEL G. ; et
al. |
April 3, 2014 |
EXPANDABLE PROXIMAL REAMER
Abstract
A kit for reaming a portion of a cavity for use in implanting a
prosthesis. The kit includes a distal reamer for reaming a distal
portion of the long bone and a proximal reamer for reaming a
proximal portion of the long bone. The kit further includes a pilot
shaft for insertion into a reamed distal portion and attachment to
the proximal reamer during the reaming of the proximal portion. At
least one of the distal reamer, proximal reamer, and pilot shaft is
expandable, such that at least one of the distal reamer, proximal
reamer, and pilot shaft includes a body having a plurality of
slots, a plurality of cutting edges extending through the slots,
and an actuator rod including a gear for engaging the plurality of
cutting edges such that when the actuator rod is turned in one
direction, the plurality of cutting edges expands outwardly through
the slots.
Inventors: |
SACKETT; SAMUEL G.; (FORT
WAYNE, IN) ; CARR; JONATHAN E.; (WARSAW, IN) ;
MCCLEARY; LARRY G.; (WARSAW, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SACKETT; SAMUEL G.
CARR; JONATHAN E.
MCCLEARY; LARRY G. |
FORT WAYNE
WARSAW
WARSAW |
IN
IN
IN |
US
US
US |
|
|
Family ID: |
39591235 |
Appl. No.: |
14/100367 |
Filed: |
December 9, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13069470 |
Mar 23, 2011 |
8632546 |
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14100367 |
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11858939 |
Sep 21, 2007 |
7935117 |
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13069470 |
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11743325 |
May 2, 2007 |
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11858939 |
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Current U.S.
Class: |
606/80 |
Current CPC
Class: |
A61B 17/164 20130101;
A61B 17/1617 20130101; A61B 17/1624 20130101; A61B 17/1668
20130101; A61B 2090/061 20160201 |
Class at
Publication: |
606/80 |
International
Class: |
A61B 17/16 20060101
A61B017/16 |
Claims
1. A kit for reaming a portion of a long bone cavity for use in
implanting a joint prosthesis, the reamers for cooperation with
portions of an orthopaedic implant component, the kit comprising: a
distal reamer for reaming a distal portion of the long bone; a
proximal reamer for reaming a proximal portion of the long bone;
and a pilot shaft for insertion into a reamed distal portion and
attachment to the proximal reamer during the reaming of the
proximal portion; wherein at least one of the distal reamer,
proximal reamer, and pilot shaft is expandable, such that the at
least one of the distal reamer, proximal reamer, and pilot shaft
includes a body having a plurality of slots, a plurality of cutting
edges extending through the slots, and an actuator rod including a
gear for engaging the plurality of cutting edges such that when the
actuator rod is turned in one direction, the plurality of cutting
edges expands outwardly through the slots.
2. The kit of claim 1, wherein the expandable body is cone-shaped
including a proximal region and a distal region and the diameter of
the proximal region of the reamer is expanded more relative to the
distal region.
3. The kit of claim 1, wherein the gear of the actuator rod engages
the cutting edges such that when the actuator rod is turned in an
opposite direction the cutting edges retract into the slots.
4. The kit of claim 1, wherein the gear of the actuator rod is a
long gear that extends the length of each of the plurality of
cutting edges and engages a plurality of ridges on the plurality of
cutting edges.
5. The kit of claim 4, wherein the plurality of cutting edges
include a cutting side and a ridge side such that the ridge side
includes the ridges.
6. The kit of claim 1 wherein each of the distal reamer, proximal
reamer, and pilot shaft is expandable.
Description
RELATED APPLICATIONS
[0001] This application is a divisional patent application of U.S.
patent application Ser. No. 13/069,470, filed on Mar. 23, 2011,
which was a divisional of U.S. patent application Ser. No.
11/858,939 (which issued as U.S. Pat. No. 7,935,117) of the same
title and filed on Sep. 21, 2007, which was a continuation-in-part
of U.S. Ser. No. 11/743,325, filed on May 2, 2007 and now
abandoned, all of which are herein incorporated by reference in
their entireties.
TECHNICAL FIELD OF THE INVENTION
[0002] The present invention relates generally to the field of
orthopaedics, and more particularly, to an implant for use in
arthroplasty.
BACKGROUND OF THE INVENTION
[0003] Patients who suffer from the pain and immobility caused by
osteoarthritis and rheumatoid arthritis have an option of joint
replacement surgery. Joint replacement surgery is quite common and
enables many individuals to function properly when it would not be
otherwise possible to do so. Artificial joints are usually
comprised of metal, ceramic and/or plastic components that are
fixed to existing bone.
[0004] Such joint replacement surgery is otherwise known as joint
arthroplasty. Joint arthroplasty is a well-known surgical procedure
by which a diseased and/or damaged joint is replaced with a
prosthetic joint. In a typical total joint arthroplasty, the ends
or distal portions of the bones adjacent to the joint are resected
or a portion of the distal part of the bone is removed and the
artificial joint is secured thereto.
[0005] There are known to exist many designs and methods for
manufacturing implantable articles, such as bone prostheses. Such
bone prostheses include components of artificial joints such as
elbows, hips, knees and shoulders.
[0006] Currently in total hip arthroplasty, a major critical
concern is the instability of the joint. Instability is associated
with dislocation. Dislocation is particularly a problem in total
hip arthroplasty.
[0007] Factors related to dislocation include surgical technique,
implant design, implant positioning and patient related factors. In
total hip arthroplasty, implant systems address this concern by
offering a series of products with a range of lateral offsets, neck
offsets, head offsets and leg lengths. The combination of these
four factors affects the laxity of the soft tissue. By optimizing
the biomechanics, the surgeon can provide a patient a stable hip
that is more resistant to dislocation.
[0008] In order to accommodate the range of patient arthropathy
metrics, a wide range of hip implant geometries are currently
manufactured by DePuy Orthopaedics, Inc., the assignee of the
current application, and by other companies. In particular, the
5-ROM.RTM. total hip systems offered by DePuy Orthopaedics, Inc.
may include up to six neck offsets per stem diameter, six head
lengths and one leg length adjustment. The combination of all these
biomechanic options is rather complex.
[0009] Anteversion of a total hip system is closely linked to the
stability of the joint. Improper anteversion can lead to
dislocation and patient dissatisfaction. Anteversion control is
important in all hip stems. However, it is a more challenging issue
with the advent of stems with additional modularity.
[0010] The prior art has provided for some addressing of the
anteversion problem. For example, the current S-ROM.RTM. stems have
laser markings on the medial stem and the proximal sleeve. This
marking enables the surgeon to measure relative alignment between
these components. Since the sleeve has infinite anteversion, it is
not necessarily oriented relative to a bony landmark that can be
used to define anteversion. In fact, the current sleeves are
sometimes oriented with the spout pointing directly laterally into
the remaining available bone.
[0011] When a primary or index total joint arthroplasty fails, a
revision procedure is performed in which the index devices (some or
all) are removed. Quite often the remaining bone is significantly
compromised compared to a primary hip procedure. Significant bone
loss is observed, often with a lack of bone landmarks typically
used for alignment.
[0012] In a common step in the surgical procedure known as total
hip arthroplasty, a trial or substitute stem is first implanted
into the patient. The trial is utilized to verify the selected size
and shape of the implant in situ on the patient and the patient is
subjected to what is known as a trial reduction. This trial
reduction represents moving the joint, including the trial implant
through selected typical motions for that joint. Current hip
instruments provide a series of trials of different sizes to help
the surgeon assess the fit and position of the implant. Trials,
which are also known as provisionals, allow the surgeon to perform
a trial reduction to assess the suitability of the implant and the
implant's stability prior to final implant selection. In order to
reduce inventory costs and complexity, many trialing systems are
modular. For example, in the Excel.TM. Instrument System, a product
of DePuy Orthopaedics, Inc., there is a series of broaches and a
series of neck trials that can be mixed and matched to represent
the full range of implants. There is a single fixed relationship
between a broach and a neck trial, because these trials represent a
system of monolithic stem implants.
[0013] Likewise, in the current S-ROM.RTM. instrument systems
provided by DePuy Orthopaedics, Inc., there are neck trials,
proximal body trials, distal stem trials, head trials and sleeve
trials. By combining all of these components, the implant is
represented. Since the S-ROM.RTM. stem is modular and includes a
stem and a sleeve, the angular relationship or relative anteversion
between the neck and the sleeve is independent and represented by
teeth mating between the neck and the proximal body trial. The
proximal body trial has fixed transverse bolts that are keyed to
the sleeve in the trialing for straight, primary stems. The long
stem trials do not have the transverse bolts and are thus not
rotationally stable during trial reduction and therefore are not
always used by the surgeon.
[0014] With the introduction of additional implant modularity, the
need for independent positioning of the distal stem, proximal body
and any sleeve that comprise the implants is required. Currently,
modular stems for one replacement may come with up to thirty four
different sleeve geometries, requiring up to seven different reamer
attachments and corresponding pilot shafts to prepare the cone
region of the sleeve.
[0015] While the prior art has attempted to reduce the steps in
surgical techniques and improve the ability to precisely remove
bone to prepare the bone for receiving a proximal component, the
need remains for a system and apparatus to reduce the number of
components required to perform hip arthroplasty.
[0016] The present invention is directed to alleviate at least some
of the problems with the prior art.
SUMMARY OF THE INVENTION
[0017] According to one embodiment of the present invention, a
reamer for reaming a portion of a long bone cavity for use in
implanting a joint prosthesis is provided. The reamer is for
cooperation with a portion of an orthopaedic implant component and
includes an expandable body that is adapted to adjust between a
plurality of diameters. A plurality of cutting edges extending
outwardly from the body is also included. The edges are adapted for
cooperation with bone, such that the cutting edges expand as the
expandable body expands.
[0018] According to another embodiment of the present invention, a
method for reaming a portion of a long bone cavity for use in
implanting a joint prosthesis is provided. The reamer is used in
cooperation with a portion of an orthopaedic implant component. The
method includes reaming a distal portion of the long bone using a
distal reamer as well as reaming a proximal portion of the long
bone using a proximal reamer. At least one of the distal reamer and
proximal reamer is an expandable reamer, such that one of the
distal reamer and proximal reamer includes an expandable body
adapted to adjust between a plurality of diameters.
[0019] According to yet another embodiment of the present
invention, a kit for reaming a portion of a long bone cavity for
use in implanting a joint prosthesis is provided. The reamers are
used in cooperation with portions of an orthopaedic implant
component. The kit includes a distal reamer for reaming a distal
portion of the long bone, a proximal reamer for reaming a proximal
portion of the long bone, and a pilot shaft for insertion into a
reamed distal portion and attachment to the proximal reamer during
the reaming of the proximal portion. At least one of the distal
reamer, proximal reamer, and pilot shaft is expandable, such that
one of the distal reamer, proximal reamer, and pilot shaft includes
an expandable body adapted to adjust between a plurality of
diameters.
[0020] According to another embodiment of the present invention, a
reamer for reaming a portion of a long bone cavity for use in
implanting a joint prosthesis is provided. The reamer is for
cooperation with a portion of an orthopaedic implant component and
includes a body. The body includes a hollow housing having a
plurality of slots adapted to adjust between a plurality of
diameters. A plurality of cutting edges extend through the
plurality of slots and the edges are adapted for cooperation with
bone. Each of the plurality of cutting edges includes a plurality
of ridges. An actuator rod is included and has a gear that engages
the plurality of ridges, such that when the actuator rod is turned
in one direction, the plurality of cutting edges expands through
the plurality of slots to alter the cutting diameter of the
reamer.
[0021] According to yet another embodiment of the present
invention, a method for reaming a portion of a long bone cavity for
use in implanting a joint prosthesis is provided. The reamer
cooperates with a portion of an orthopaedic implant component. The
method includes reaming a cylindrical portion of the long bone
using a cylindrical reamer and reaming a conical portion of the
long bone using a conical reamer. At least one of the cylindrical
reamer and conical reamer is an expandable reamer, such that at
least one of the cylindrical reamer and conical reamer includes a
body having a plurality of slots. The expandable reamer also
includes a plurality of cutting edges extending through the slots
and an actuator rod including a gear for engaging the plurality of
cutting edges such that when the actuator rod is turned in one
direction, the plurality of cutting edges expands outwardly through
the slots to alter the cutting diameter of the reamer.
[0022] According to another embodiment of the present invention, a
kit for reaming a portion of a long bone cavity for use in
implanting a joint prosthesis is provided. The reamers cooperate
with portions of an orthopaedic implant component. The kit
comprises a distal reamer for reaming a distal portion of the long
bone, a proximal reamer for reaming a proximal portion of the long
bone, and a pilot shaft for insertion into a reamed distal portion
and attachment to the proximal reamer during the reaming of the
proximal portion. At least one of the distal reamer, proximal
reamer, and pilot shaft is expandable, such that at least one of
the distal reamer, proximal reamer, and pilot shaft includes a body
having a plurality of slots, a plurality of cutting edges extending
through the slots, and an actuator rod including a gear for
engaging the plurality of cutting edges such that when the actuator
rod is turned in one direction, the plurality of cutting edges
expands outwardly through the slots to alter the cutting diameter
of the reamer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] For a more complete understanding of the present invention
and the advantages thereof, reference is now made to the following
description taken in connection with the accompanying drawings, in
which:
[0024] FIG. 1 is a plan view of a distal reamer in position in a
long bone for preparing a bone canal for receiving a long bone
prosthetic stem;
[0025] FIG. 2 is a plan view of an expandable distal reamer
according to one embodiment of the present invention;
[0026] FIG. 2a is a plan view of the expandable distal reamer of
FIG. 2 in an expanded position, including a view of the internal
components of the reamer;
[0027] FIG. 3 is a plan view of a proximal reamer in position in a
long bone for preparing a bone canal for receiving a long bone
prosthetic stem;
[0028] FIG. 4 is a plan view of an expandable proximal reamer
according to one embodiment of the present invention;
[0029] FIG. 4a is a plan view of the expandable proximal reamer of
FIG. 4 in an expanded position, including a view of the internal
components of the reamer;
[0030] FIG. 5 is a plan view of an expandable pilot shaft according
to another embodiment of the present invention.
[0031] FIG. 5a is a plan view of the expandable pilot shaft of FIG.
5, including a view of the internal components of the shaft.
[0032] FIG. 6 is a plan view of an expandable proximal reamer
according to another embodiment of the present invention.
[0033] FIG. 7 is a plan view of an expandable proximal reamer
according to yet another embodiment of the present invention.
[0034] FIG. 7a is a plan view of the expandable proximal reamer of
FIG. 7 in an expanded state.
[0035] FIG. 8 is a flow chart illustrating a method of using an
expandable reamer according to one embodiment of the present
invention.
[0036] FIG. 9 is an exploded view of the expandable reamer
according to another embodiment of the present invention.
[0037] FIG. 10 is a close-up view of the body and cutting edges of
the expandable reamer of FIG. 9.
[0038] FIG. 11a is a plan view of an expandable reamer of FIG.
9.
[0039] FIG. 11b is a plan view of the expandable reamer of FIG. 9
in an expanded state.
DETAILED DESCRIPTION OF THE INVENTION
[0040] Embodiments of the present invention and the advantages
thereof are best understood by referring to the following
descriptions and drawings, wherein like numerals are used for like
and corresponding parts of the drawings.
[0041] Referring now to FIG. 1 a long bone or femur 2 for use with
the present invention is shown. The femur 2 includes an
intermedullary canal 4 into which the prosthesis of the present
invention may be inserted. The femur 2 is resected along resection
line 6 by, for example, a power tool, for example, a saw. The
resecting of the long bone or femur 2 exposes the intermedullary
canal 4 of femur 2. A distal or cylindrical reamer 8 that may be a
standard commercially available reamer is positioned in the
intermedullary canal 4 of the long bone 2 to form cavity 10 for
receiving an orthopedic joint implant. The distal reamer 8 includes
a plurality of longitudinally extending channels, or flutes 12
which are used to remove bone and other biological matter from the
intermedullary canal 4 to form the cavity 10. The distal reamer 8
may be rotated by use of a connector 14 positioned on the distal
reamer 8. The connector 14 may be any standard connector for
example a Hudson or an A-O connector. The connector 14 is used to
connect to a power tool 15 for rotating the distal reamer 8. The
power tool 15 may be any standard power tool. It should be
appreciated that the distal reamer 8 may be rotated through the use
of the connector 14 by a hand tool for example a "T" shaped
handle.
[0042] The diameter "D" of the distal reamer 8 is determined by the
size of the distal stem (not shown) that is to be implanted into
the femur 2. Because of variances in human anatomy, there are
numerous sizes of distal stems that can be implanted. Therefore,
there are numerous sizes of reamers 8 that can also be used. The
large number of reamers 8 can increase production and manufacturing
costs, as well as create problems during the surgery should the
doctor select the wrong size distal reamer 8 to be used.
[0043] Turning now to FIG. 2, an embodiment of an expandable distal
reamer 8a is shown. Because the distal reamer 8a is expandable, the
diameter D.sub.a of the distal reamer 8a is variable, unlike the
fixed diameters of the prior art distal reamers.
[0044] As shown in FIG. 2, the expandable distal reamer 8a includes
a proximal portion 16 and a distal cutting portion 17. The proximal
portion 16 includes at least two gears 18, 20 that are in contact
with each other such that when the gear 18 is rotated, the gear 20
also rotates. Similar to the distal reamer 8 of FIG. 1, the
expandable distal reamer 8a includes flutes 12a. The flutes 12a
expand outwardly from the reamer 8a when the gears 18, 20 are
activated. The reamer 8a also includes a plurality of slits, or
cuts, 22a, 22b around its circumference. Such slits 22a, 22b allow
the diameter D.sub.a of the expandable distal reamer 8a to enlarge
when the gears 18, 20 are rotated.
[0045] The gear 18 may be activated by inserting a chuck (not
shown) into a hole 24 of the proximal portion 16 and then rotating
the chuck. Alternatively, a gauge 25 (FIG. 2a) may be inserted into
the hole 24 until it engages the gear 18 and rotated a desired
amount. The gauge 25 may include markers 27 (FIG. 2a) to allow the
user to know when to stop rotating the gauge. Any other known
method for activating a gear may also be utilized.
[0046] Once the gears 18, 20 are activated, the gear 20 forces a
cone 26 down through the proximal portion 16 into the distal
cutting portion 17. As the cone 26 moves downwardly, the cone's
increasing diameter forces the distal cutting portion 17 to become
enlarged. As stated above, the reamer 8a includes slits 22a, 22b.
These slits 22a, 22b allow the distal portion 17 to expand as the
cone 26 pushes further into the distal portion 17. Therefore, the
diameter Da of the reamer 8a also increases.
[0047] In FIG. 2a, the gauge 25 is shown inserted into the top of
the expandable distal reamer 8a and the distal reamer 8a is shown
in an expanded position, having a radius D.sub.b. When the gauge 25
is inserted, it engages the gear 18. The gauge 25 may include
markings 27 that correlate to the size of the diameter D.sub.a of
the expandable distal reamer 8a. In other words, if the surgeon or
other healthcare professional rotates the gauge 25 a particular
amount, the marking 27 indicates that the rotation correlates to a
particular diameter D.sub.a of the expandable distal reamer 8a.
Furthermore, as the gauge 25 is rotated, the slits 22a, 22b enlarge
as shown in FIG. 2a, creating the larger diameter D.sub.b.
[0048] As shown in FIGS. 2 and 2a, the diameter D.sub.a of the
expandable distal reamer 8a may be enlarged through mechanical
means such as gears 18, 20. However, other devices, such as
pneumatic or hydraulic mechanisms could also be used to adjust the
diameter D.sub.a of the expandable distal reamer 8a. In addition,
other mechanical devices, such as cross-bars and/or levers could be
used to increase the diameter D.sub.a of the expandable distal
reamer 8a.
[0049] After the distal region of the femur 2 is reamed, the
proximal portion must then be reamed. As shown in FIG. 3, a conical
or proximal reamer 30 is used to form cavity 10 for receiving an
orthopedic joint implant. The proximal reamer 30 includes a
plurality of longitudinally extending channels or flutes 32 which
are used to remove bone and other biological matter from the femur
2 to form a cavity 33 having a cone-shape, with a diameter varying
between a diameter d.sub.1 to d.sub.2, which is the same shape and
diameter range of the cone-shaped proximal reamer 30. The proximal
reamer 30 may be rotated by use of a connector 34 positioned on the
proximal reamer 30. The connector 34 may be any standard connector
for example a Hudson or an A-O connector. The connector 34 is used
to connect to a power tool 35 for rotating the proximal reamer 30.
The power tool 35 may be any standard power tool. It should be
appreciated that the proximal reamer 30 may be rotated through the
use of the connector 34 by a hand tool for example a "T" shaped
handle. The proximal reamer 30 is coupled to a pilot shaft 36 that
fits into the reamed cavity 10. The pilot shaft 36 ensures that the
proximal reamer 30 goes into the canal and reams straight.
[0050] Turning now to FIG. 4, an expandable proximal reamer 30a
according to one embodiment of the present invention is
illustrated. Because the proximal reamer 30a is expandable, the
diameters d.sub.a1-d.sub.a2 of the proximal reamer 30a are
variable, unlike the fixed diameters of the prior art proximal
reamers.
[0051] Similar to the distal reamer 8a shown in FIGS. 2 and 2a
above, the proximal reamer includes a proximal portion 37 and a
distal cutting portion 38. The proximal portion 37 includes at
least two gears 39, 40 that are in contact with each other such
that when the gear 39 is rotated, the gear 40 also rotates. Similar
to the proximal reamer 30 of FIG. 3, the expandable proximal reamer
30a includes flutes 32a. The flutes 32a expand outwardly from the
reamer 30a when the gears 39, 40 are activated. The reamer 30a also
includes a plurality of slits, or cuts, 42a, 42b, around its
circumference. Such slits 42a, 42b, allow the diameters d.sub.a1
and d.sub.a2 of the expandable proximal reamer 30a to enlarge when
the gears 39, 40 are rotated.
[0052] The gear 39 may be activated by inserting a chuck (not
shown) into a hole 43 of the proximal portion 16 and then rotating
the chuck. Alternatively, a gauge 44 (FIG. 4a) may be inserted into
the hole 43 until it engages the gear 39 and rotated a desired
amount. The gauge 44 may include markers 46 (FIG. 4a) to allow the
user to know when to stop rotating the gauge. Any other known
method for activating a gear may also be utilized.
[0053] Once the gears 39, 40 are activated, the gear 40 forces a
cone 48 down through the proximal portion 37 into the distal
cutting portion 38. As the cone 48 moves downwardly, the cone's
increasing diameter forces the distal cutting portion 38 to become
enlarged. As stated above, the reamer 30a includes slits 42a, 42b.
These slits 42a, 42b allow the distal portion 38 to expand as the
cone 48 pushes further into the distal portion 38. Therefore, the
diameters d.sub.a1 and d.sub.a2 of the proximal reamer 30a also
increase.
[0054] In FIG. 4a, the gauge 44 is shown inserted into the top of
the expandable proximal reamer 30a and the reamer is shown in an
expanded position having diameters d.sub.b1 and d.sub.b2 that are
greater than the diameters d.sub.a1 and d.sub.a2. The gauge 44 may
include markings 46 that correlate to the size of the diameters
d.sub.a1 and d.sub.a2 of the expandable proximal reamer 30a. In
other words, if the surgeon or other healthcare professional
rotates the gauge 44 a particular amount, the marking 46 indicates
that the rotation correlates to particular diameters d.sub.a1 and
d.sub.a2 of the expandable proximal reamer 30a. Furthermore, as the
gauge 44 is rotated, the slits 42a, 42b enlarge as shown in FIG.
4a, creating the larger diameters d.sub.b1 and d.sub.b2. In this
embodiment, because of the conical shape of the reamer 30a, as the
gears 39, 40 are rotated, the diameter d.sub.a1 increases more
relative to the diameter d.sub.a2. In other words, proximal portion
37 is expanded more relative to the distal portion 38.
[0055] As shown in FIGS. 4 and 4a, the diameters d.sub.a1 and
d.sub.a2 of the expandable proximal reamer 30a may be enlarged
through mechanical means such as gears 39, 40. However, other
devices, such as pneumatic or hydraulic mechanisms could also be
used to adjust the diameters d.sub.a1 and d.sub.a2 of the
expandable proximal reamer 30a. In addition, other mechanical
devices, such as cross-bars and/or levers could be used to increase
the diameters d.sub.a1 and d.sub.a2 of the expandable proximal
reamer 30a.
[0056] Turning now to FIGS. 5 and 5a, an alternative embodiment of
a pilot shaft 50 is shown. As discussed above, a pilot shaft is
attached to the proximal reamer to ensure that the reamer properly
extends downwardly into the canal. Also as discussed above, because
the distal reamer 8 may come in various sizes, the pilot shaft must
also come in a variety of sizes. Therefore, to cut-down on
manufacturing costs and to reduce the possibility of confusion in
the operating room, in one embodiment of the present invention, the
pilot shaft 50 is also adjustable. As shown in FIG. 5, the pilot
shaft 50 includes a proximal portion 52, a distal portion 54 and a
central portion 56. The central portion 56 includes a sleeve 58
that engages two threaded screws 60, 62. As the sleeve 58 is
rotated, the threaded screws 60, 62 are pushed into openings 64, 66
in the proximal and distal portions 52, 54. The proximal and distal
portions 52, 54 each include slits 68, 70 that open as the threaded
screws 60, 62 are pushed into the openings 64, 66 (as shown in FIG.
5a). Thus, the operator is able to adjust the diameter of the pilot
shaft 50 to match the diameter of the reamed canal 10. In the
embodiments illustrated in FIGS. 5 and 5a, the pilot shaft 50 is
adjusted from having a diameter of D.sub.c to D.sub.d. As shown in
FIGS. 5 and 5a, the pilot shaft 50 also includes a connectable
mechanism such as a threaded portion 72 for attachment to the
expandable proximal reamer 30a. Alternatively, the threaded portion
72 may also attach to a miller shell or a proximal body trial (not
shown).
[0057] Turning now to FIG. 6, an alternative embodiment of an
expandable proximal reamer 80 is illustrated. In this embodiment,
the expandable proximal reamer 80 includes an upper conical recess
82. A threaded expansion rod 84 has a threaded end 86 and is
inserted into the upper conical recess 82. As the threaded
expansion rod 84 is advanced through the upper conical recess 82,
the expandable reamer 80 is widened through the use of a slit 88.
The user may thus adjust the diameters of the expandable reamer
80.
[0058] As shown in FIG. 6, the threaded expansion rod 84 may
include a gauge 90, allowing the user to determine the diameter of
the reamer 80. Also, the rod 84 may include upper and lower support
rods 92, 94 that extend into the reamer 80 to keep the reamer 80
and the rod 84 rigid during use. Either or both of the support rods
may also be used in connection with any of the embodiments
discussed above.
[0059] In all of the embodiments discussed above, whether for
distal reamers, proximal reamers, or pilot shafts, the various
gauges and/or markings may also include preset stops that
correspond to certain sizes. Such preset stops would make it easier
for a user to accurately stop adjusting at the correct diameter.
The preset stops may be fashioned out of notches in a thread or any
other known mechanism.
[0060] Turning now to FIG. 7, another embodiment of an expandable
proximal reamer 100 is illustrated. In this embodiment, the
proximal reamer 100 includes a screw 102 that extends outwardly
from the proximal reamer 100. The screw 102 has a threaded portion
104a that is threadably engaged with threaded portions 104b, 104c
of supports 105. The supports 105 provide the reamer 100 with
support during cutting, enabling the reamer 100 to expand, yet
still maintain its strength and rigidity.
[0061] As a user rotates the screw 102, the threads 104a cause the
threaded portions 140b, 104c to also rotate. The threaded portions
104b, 104c are also threadably engaged with a thread 104d, such
that when the threaded portions 104b, 104c are rotated, the
threaded portion 104d also rotates. The threaded portion 104d is
coupled to a cone 106, such that as the threaded portion 104d
rotates, the cone 106 moves in a downward direction 112 (FIG. 7a),
causing the proximal reamer 100 to expand outwardly in the
direction indicated by arrows 114. This also causes the supports
105 to move outwardly in directions 110 as shown in FIG. 7a.
[0062] As shown in FIGS. 7 and 7a, the proximal reamer 100 is
coupled to a pilot shaft 108, such that as the cone 106 moves
downwardly, the pilot shaft 108 may also expand in an outward
direction as indicated by arrows 114 (FIG. 7a).
[0063] Turning now to FIG. 8, a method for utilizing the expandable
reamers is shown. At step s200, the femur is resected. Next, the
user selects the distal reamer to be used at step s202. If an
expandable distal reamer is to be used, then at step s202, the user
then adjusts the diameter of the distal reamer as described above.
At step s204, the distal reamer is inserted and the distal portion
of the long bone is reamed (step s206). Next, at step s208, the
proximal reamer is selected. If the proximal reamer is an
adjustable reamer, the user will adjust the proximal reamer to the
appropriate diameter. If the proximal reamer is not adjustable,
then the user must select a proximal reamer with an appropriate
diameter from a set of reamers. Next, at step s210, the pilot shaft
is selected or adjusted as necessary. At step s212, the proximal
reamer is attached to a pilot shaft. The proximal reamer and shaft
are inserted into the proximal portion of the long bone and the
reamed distal portion, respectively at step s214. The proximal
portion is then reamed at step s216. The rest of the reaming and
implantation process is then completed in any of the ways customary
and known in the prior art. It should be noted that although in
this example, both the proximal reamer and the distal reamer were
expandable, that in some embodiments, only one of the reamers may
be expandable. Also, while some embodiments refer to an adjustable
pilot shaft, in other embodiments, the pilot shafts of the prior
art may be attached to the proximal reamers.
[0064] Turning now to FIG. 9, an exploded view of another
embodiment of an expandable reamer 300 is shown. The expandable
reamer 300 includes a handle 302, knob 304, actuator rod 306, body
308, a plurality of cutting edges 310a, 310b, 310c, 310d and a
pilot shaft 311.
[0065] Turning now to FIG. 10, the relationship between the body
308 and the cutting edges 310 will be described. The body 308
includes a plurality of slots 312a, 312b, 312c, 312d. As shown, the
plurality of cutting edges 310a, 310b, 310c, 310d extend through
the slots 312a, 312b, 312c, 312d. Each of the cutting edges 310a,
310b, 310c, 310d include a cutting edge side 313 and an opposite
side 314. The opposite side includes a plurality of gear teeth
316.
[0066] The plurality of gear teeth 316 engages a gear 318 on the
actuator rod 306. The gear teeth 316 and the gear 318 are engaged
such that when an operator turns the rod 306, the gear 318 causes
the gear teeth 316 to move, thereby expanding a diameter of the
reamer 300. The diameter expansion will be explained in more detail
in reference to FIGS. 11a and 11b below.
[0067] Turning back to FIG. 9, the knob 304 includes a pin 320 that
engages a slot 322 in the actuator rod 306. The pin 320 also
engages a notched slot 324 in the handle 302. The notched slot 324
allows the user to lock the pin 320 at certain locations, thereby
locking the actuator rod 306 (and, as a result the cutting edges
310a, 310b, 310c, 310d) in a particular location. There is also
included a spring 326 that aids in holding the pin 320 in one of
the notches of the notched slot 324. To release the pin 320, the
user would pull up and turn the handle 302 to disengage the pin 320
from the particular notch in the notched slot 324 with or without
the assistance of other gears and gear ratios. In other words, in
some embodiments, there may be additional gears that engage the
gear 318. The additional gears allow the surgeon or other user to
move the actuator rod 306 more than the gear 318 moves.
[0068] Turning now to FIGS. 11a and 11b, the reamer 300 will be
shown in non-expanded and expanded views. In the non-expanded view
shown in FIG. 11a, the cutting edges 310a, 310b,310c, 310d creating
a cutting diameter D.sub.e. As shown in FIG. 11b, once the knob 304
is turned, the cutting edges 310a, 310b, 310c, 310d create an
expanded cutting diameter D.sub.f that is larger than the cutting
diameter D.sub.e.
[0069] The embodiment illustrated in FIGS. 9-11b is a proximal
reamer that is generally cone-shaped. However, the reamer 300 may
also be a distal reamer, and be generally cylindrical-shaped. In
other embodiments, the cutting edges 310a, 310b, 310c, 310d may be
replaced with non-cutting edges and the device may be used as an
expandable instrument. In other words, the concept of the body 308,
edges 310a, 310b, 310c, 310d, and actuator rod 306 may be used in
any type of instrument where it is desirable to have an expandable
diameter. Although four cutting edges 310a, 310b, 310c, 310d have
been illustrated, any number of cutting edges may be used.
[0070] In some embodiments of the present invention, the reamer may
be a combination of the reamer 300 of FIGS. 9-11b and the reamer
30a of FIG. 4. In this alternative embodiment, the reamer utilizes
the gear 318 and cutting edges 310a, 310b, 310c, 310d of FIG. 9 as
well as the cone 48 from FIG. 4. As described in reference to FIG.
4, the increasing diameter of the cone 48 forces the cutting edges
310a, 310b, 310c, 310d to expand. Although four cutting edges have
been described any number of cutting edges may be use.
[0071] In some embodiments of the present invention, a kit for
reaming the long bone is provided, including distal reamers,
proximal reamers, and pilot shafts. The kit includes at least one
reamer that is an expandable reamer. In some embodiments, both the
distal reamer and the proximal reamers will be expandable. In other
embodiments, only one of the types of reamer will be expandable. In
some embodiments, the pilot shaft may also be expandable.
[0072] According to some embodiments of the present invention, the
expandable reamers may be able to expand to all sizes required for
that type of reamer. In other embodiments, the expandable reamers
may only expand through a range, and a plurality of reamers may
still be required. For example, if the expandable reamer is a
proximal reamer, a kit may include three expandable proximal
reamers. Each expandable proximal reamer in such a kit has a
diameter that is variable within a range.
[0073] Although the present invention and its advantages have been
described in detail, it should be understood that various changes,
substitutions, and alterations can be made therein without
departing from the spirit and scope of the present invention as
defined by the appended claims.
* * * * *