U.S. patent application number 11/348990 was filed with the patent office on 2006-08-17 for tibial trialing assembly and method of trialing a tibial implant.
This patent application is currently assigned to Zimmer Technology, Inc.. Invention is credited to Brian D. Byrd, Scott Lazar, Kristina J. Straszheim-Morley, Dwight T. Todd.
Application Number | 20060184176 11/348990 |
Document ID | / |
Family ID | 36145356 |
Filed Date | 2006-08-17 |
United States Patent
Application |
20060184176 |
Kind Code |
A1 |
Straszheim-Morley; Kristina J. ;
et al. |
August 17, 2006 |
Tibial trialing assembly and method of trialing a tibial
implant
Abstract
A trialing assembly for use during knee replacement procedures
to determine size and position of a tibial plate implant as well as
the size and thickness of the articular surface prior to
implantation of the implant. The trialing assembly includes a
broaching plate having a tibia engaging bottom surface adapted for
placement atop a tibia and an opposite top surface, the bottom and
top surfaces extending between an anterior edge and a posterior
edge of the broaching plate. The broaching plate includes an
anterior rail and a posterior rail protruding superiorly from the
top surface and extending along the anterior and posterior edges,
respectively. A trialing plate is configured to removably fit atop
the broaching plate between the anterior and posterior rails. The
trialing plate includes an engagement member extending from a
superior surface of the trialing plate and adapted to engage with
an articular surface provisional.
Inventors: |
Straszheim-Morley; Kristina J.;
(Warsaw, IN) ; Todd; Dwight T.; (Columbia City,
IN) ; Byrd; Brian D.; (North Webster, IN) ;
Lazar; Scott; (Cromwell, IN) |
Correspondence
Address: |
ZIMMER TECHNOLOGY - BAKER & DANIELS
111 EAST WAYNE STREET, SUITE 800
FORT WAYNE
IN
46802
US
|
Assignee: |
Zimmer Technology, Inc.
|
Family ID: |
36145356 |
Appl. No.: |
11/348990 |
Filed: |
February 7, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60653902 |
Feb 17, 2005 |
|
|
|
Current U.S.
Class: |
606/88 |
Current CPC
Class: |
A61B 17/1739 20130101;
A61B 17/1775 20161101; A61F 2/4684 20130101; A61B 17/1764 20130101;
A61F 2/389 20130101 |
Class at
Publication: |
606/088 |
International
Class: |
A61B 17/58 20060101
A61B017/58 |
Claims
1. A trialing assembly for use during a knee replacement procedure
to size and prepare a resected tibia for receiving a tibial implant
and to trial an articular surface provisional, said trialing
assembly comprising: a broaching plate having an outer periphery,
said broaching plate including a bottom surface adapted for
placement atop the resected tibia and an opposite top surface, and
a plurality of alignment rails protruding from said top surface,
each alignment rail extending adjacent at least a portion of said
outer periphery; and a trialing plate removably positionable atop
said broaching plate between said plurality of alignment rails,
said trialing plate having a superior surface and an articular
surface provisional engagement member extending superiorly from
said superior surface.
2. The trialing assembly of claim 1 wherein said plurality of
alignment rails includes an anterior rail extending adjacent an
anterior portion of said outer periphery and a posterior rail
extending adjacent a posterior portion of said outer periphery.
3. The trialing assembly of claim 1 wherein said trialing plate
overlies substantially all of said top surface of said broaching
plate when said trialing plate is positioned atop said broaching
plate.
4. The trialing assembly of claim 1 wherein said broaching plate
includes at least one fastener hole configured for receipt of a
fastener therethrough for engagement with the resected tibia.
5. The trialing assembly of claim 4 wherein said fastener includes
a head, said head engaging, and extending superiorly from, said top
surface of said broaching plate when said fastener is received
within said at least one fastener hole, said trialing plate
including at least one opening, said at least one opening aligned
with said at least one fastener hole and receiving said fastener
head when said trialing plate is positioned atop said broaching
plate.
6. The trialing assembly of claim 1 wherein said engagement member
includes a trialing plate removal element.
7. The trialing assembly of claim 1 wherein each of said plurality
of alignment rails includes an upper surface, said superior surface
of said trialing plate being substantially level with said upper
surface of each of said plurality of alignment rails when said
trialing plate is positioned atop said broaching plate.
8. A trialing assembly for trialing an articular surface
provisional prior to implantation of the tibial implant on a
resected tibia, the trialing assembly comprising: a broaching plate
having an outer periphery surrounding a bottom surface adapted for
placement atop the resected tibia and an opposite top surface; and
a trialing plate removably disposed atop said broaching plate and
overlying substantially all of said top surface, said trialing
plate including an articular surface provisional engagement member
extending superiorly from a superior surface of said trialing
plate.
9. The trialing assembly of claim 8 wherein said member includes a
trialing plate removal element.
10. The trialing assembly of claim 9 wherein said member includes
an outer wall, and said trialing plate removal element includes a
groove within said outer wall.
11. The trialing assembly of claim 8 wherein said broaching plate
includes at least one alignment rail protruding superiorly from
said top surface.
12. The trialing assembly of claim 11 wherein said at least one
alignment rail includes an anterior rail extending along an
anterior portion of said outer periphery and a posterior rail
extending along a posterior portion of said outer periphery.
13. The trialing assembly of claim 8 further comprising a
provisional base plate having a base plate periphery surrounding an
upper surface and an opposite lower surface, said lower surface
adapted for placement atop the resected tibia, said provisional
base plate having a stem projecting from said lower surface and
adapted for insertion into the resected tibia, said base plate
having at least one alignment rail projecting from said upper
surface, said trialing plate removably positionable atop said
provisional base plate and engagable with said at least one
alignment rail to prevent movement of said trialing plate relative
said base plate along a plane of the upper surface of said base
plate.
14. The trialing assembly of claim 1 wherein one of said plurality
of alignment rails includes a notch and said trialing plate
includes a tab, said tab configured to be received in said notch
when said trialing plate is positioned atop said broaching
plate.
15. The trialing assembly of claim 8 wherein said trialing plate
includes an inferior surface opposite said superior surface, and
wherein one of said inferior surface of said trialing plate and
said top surface of said broaching plate includes at least one
alignment member extending outwardly therefrom, and the other of
said inferior surface of said trialing plate and said top surface
of said broaching plate includes at least one alignment member
opening, said at least one alignment member opening receiving said
at least one alignment member.
16. The trialing assembly of claim 8 wherein said broaching plate
includes at least one fastener hole and said trialing plate
includes a head receiving opening aligned with each of said at
least one fastener holes.
17. The trialing assembly of claim 8 wherein said trialing plate
includes a central bore extending through said boss and said
trialing plate and configured to receive a fastener therethrough to
fix said trialing plate to the resected tibia.
18. The trialing assembly of claim 8 wherein each of said broaching
plate and trialing plate includes a plurality of augment holes each
adapted to mate with an augment provisional.
19. The trialing assembly of claim 8 wherein one of said trialing
plate and said broaching plate includes at least one alignment
rail, said at least one alignment rail engaging the other of said
trialing plate and said broaching plate to restrict movement of
said trialing plate relative said broaching plate along a plane of
said top surface.
20. A trialing assembly for trialing an articular surface
provisional, the trialing assembly comprising: a broaching plate
having a bottom surface adapted for placement atop the resected
tibia and an opposite top surface; and a trialing plate removably
disposed atop said broaching plate and overlying substantially all
of said top surface, said trialing plate having an inferior surface
adapted for placement atop said top surface and an opposite
superior surface, said trialing plate including an engagement
member extending superiorly from said superior surface, said
engagement member adapted to engage with said surface provisional,
wherein one of said broaching plate and said trialing plate
including at least one peg opening, the other of said broaching
plate and said trialing plate includes at least one peg extending
therefrom, said at least one peg received within said at least one
peg opening.
Description
PRIORITY REFERENCE
[0001] This application claims the benefit of priority under 35
U.S.C. .sctn.119(e) to provisional application Ser. No. 60/653,902,
filed in the name of Kristina J. Morley et al. on Feb. 17, 2005 and
entitled TIBIAL TRIALING ASSEMBLY AND METHOD OF TRIALING A TIBIAL
IMPLANT.
BACKGROUND
[0002] The present invention relates to trialing devices used
during knee replacement procedures to size and prepare a resected
tibia for receiving a tibial implant and to evaluate the stability
and kinematic performance of the articular surface provisional
prior to implantation of the tibial implant.
[0003] Generally, the knee is the joint between the femur and the
tibia. The knee joint is formed of a pair of condyles located at
the distal portion of the femur, a tibial plateau located at the
proximal end of the tibia and shaped to mate with the pair of
condyles, and a pair of menisci positioned between the tibial
plateau and the condyles. The femur and the tibia are connected by
ligaments, which provide stability to the knee. Such ligaments
include the posterior cruciate ligament (PCL), the lateral
collateral ligament, the medial collateral ligament, and the
anterior cruciate ligament. Significant disease of, or trauma to,
the knee may warrant replacement of the knee with a prosthetic knee
(knee implant).
[0004] A prosthetic total knee joint generally includes a femoral
component and a tibial component. The tibial component typically
includes a tibial tray or plate and a prosthetic bearing insert.
The tibial tray often includes a stem, which extends from the
bottom of the tray and is sized for insertion into the tibia. In
some knee implants, the bearing insert may be fixed to the tibial
tray such that the bearing insert is immobile relative to the
tibial tray. These knee implant designs are often referred to as
"fixed bearing" designs. In other knee implants, the bearing insert
is movably fixed to the tibial tray thereby allowing the bearing
insert to move relative to the tibial tray. These knee implant
designs are typically referred to as "mobile bearing" designs.
[0005] During mobile bearing knee replacement surgery, the surgeon
first prepares the proximal end of the tibia by resecting the
proximal tibia or, in the case of revision, removing the damaged
tibial components prior to resecting the proximal tibia. After the
tibia is prepared, a tibial sizing plate is aligned and placed on
the resected tibia, and checked for size. After the proper sizing
plate is selected and the optimal location is determined, the
sizing plate is fixed in position on the resected tibia by
inserting pins through the sizing plate and into the resected
tibia. The pins generally have cap heads that remain extended above
the surface of the sizing plate so that the pins can be extracted
upon completion of the trial. Next, the surgeon selects an
articular surface provisional, which is modeled in shape and design
after the bearing insert of the tibial component that the surgeon
proposes to implant. The surface provisional is then engaged with
the sizing plate. With the articular surface provisional in place,
the surgeon then performs trialing procedures to test the fit and
function of the articular surface provisional. Such trialing
procedures may include measuring the flexion and extension gaps,
and conducting range of motion tests, during which the
anterior/posterior and medial/lateral stability and movement may be
tested. These trialing procedures help the surgeon determine the
proper sized bearing insert. The surgeon may repeat the trialing
procedures with different sized provisionals until the desired
results are achieved.
[0006] Next, the surgeon removes the pins and the sizing plate. A
broaching plate is then positioned and carefully aligned on the
resected tibia such that pin holes in the broaching plate are
aligned with the pin holes created in the tibia by the mounting of
the sizing plate. Once aligned, the broaching plate is pinned in
place. With the broaching plate in place, a drill/broach guide is
engaged with the upper surface of the broaching plate and the
proximal tibia is drilled and/or broached to accommodate the tibial
stem of the tibial tray.
[0007] There is a need for a tibial trialing device that simplifies
and minimizes the steps of knee replacement surgery.
SUMMARY
[0008] The present invention provides a trialing assembly for use
during knee replacement procedures to prepare and size a resected
tibia for receiving a tibial implant and to evaluate the stability
and kinematic performance of the articular surface provisional
prior to implantation of the tibial implant. In one form, the
trialing assembly includes a broaching plate having an outer
periphery substantially conforming to the resected tibia. The
broaching plate includes a bottom surface adapted for placement
atop the resected tibia and an opposite top surface. The bottom and
top surfaces extend substantially between the outer periphery. The
broaching plate includes a plurality of alignment rails protruding
superiorly from the top surface and extending along at least a
portion of the outer periphery. A trialing plate is configured to
removably fit atop the broaching plate between the plurality of
alignment rails. The trialing plate has a superior surface and a
boss extending superiorly from the superior surface. The boss is
adapted to engage with an articular surface provisional.
[0009] In another form, the trialing assembly includes a broaching
plate having an outer periphery, a bottom surface adapted for
placement atop the resected tibia and an opposite top surface. The
bottom and top surfaces extend substantially between the outer
periphery. A trialing plate is removably disposed atop the
broaching plate and overlies substantially all of the top surface.
The trialing plate includes a boss extending superiorly from the
superior surface of the trialing plate. The boss is adapted to
engage with the articular surface provisional.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The above mentioned and other features and objects of this
invention, and the manner of attaining them, will become more
apparent and the invention itself will be better understood by
reference to the following description of an embodiment of the
invention taken in conjunction with the accompanying drawings,
wherein:
[0011] FIG. 1 is a perspective view of a tibial trialing assembly
according to one embodiment of the present invention;
[0012] FIG. 1A is a sectional view of the tibial trialing assembly
taken along line 1A-1A of FIG. 1;
[0013] FIG. 2 is a perspective view of the broaching plate of the
tibial trialing assembly of FIG. 1;
[0014] FIG. 3 is a perspective view of the trialing plate of the
tibial trialing assembly of FIG. 1;
[0015] FIG. 4 is an exploded perspective view of the tibial
trialing assembly fitted onto a resected tibia;
[0016] FIG. 5 is a side view of the tibial trialing assembly of
FIG. 1;
[0017] FIG. 6 is an exploded perspective view of the broaching
plate of the tibial trialing assembly of FIG. 1 fitted onto a
resected tibia and cooperating with a drill and drill guide;
[0018] FIG. 7 is a perspective view of a disassembled tibial
trialing assembly according to another embodiment of the present
invention; and
[0019] FIG. 8 is a perspective view of a tibial trialing assembly
according to another embodiment of the present invention;
[0020] FIG. 9 is a perspective view of the broaching plate of the
tibial trialing assembly of FIG. 8;
[0021] FIG. 10 is a perspective view of the trialing plate of the
tibial trialing assembly of FIG. 9;
[0022] FIG. 11 is another perspective view of the trialing plate of
FIG. 10;
[0023] FIG. 12 is a perspective view of a disassembled tibial
trialing assembly according to another embodiment of the present
invention;
[0024] FIG. 13 is a perspective view of the broaching plate of the
trialing assembly of FIG. 12;
[0025] FIG. 14 is an end view of the broaching plate of FIG.
13;
[0026] FIG. 15 is a perspective view of the trialing plate of the
trialing assembly of FIG. 12;
[0027] FIG. 16 is a perspective view of a provisional tibial base
plate in accordance with one embodiment of the present
invention;
[0028] FIG. 17 is another perspective view of the provisional
tibial base plate of FIG. 16;
[0029] FIG. 18 is a perspective view of a trialing plate according
to another embodiment of the present invention;
[0030] FIG. 19 is a side view of the trialing plate of FIG. 18;
[0031] FIG. 20 is a top perspective view of a broaching plate
according to another embodiment of the present invention; and
[0032] FIG. 21 is a bottom perspective view of the broaching plate
of FIG. 20.
[0033] Corresponding reference characters indicate corresponding
parts throughout the several views. Although the drawings represent
embodiments of the present invention, the drawings are not
necessarily to scale and certain features may be exaggerated in
order to better illustrate and explain the present invention.
Although the exemplification set out herein illustrates embodiments
of the invention, in several forms, the embodiments disclosed below
are not intended to be exhaustive or to be construed as limiting
the scope of the invention to the precise forms disclosed.
DETAILED DESCRIPTION
[0034] The present invention will now be described with reference
to the attached figures. The description below may include
references to the following terms: anterior (at or near the front
of the body, as opposed to the back of the body); posterior (at or
near the back of the body, as opposed to the front of the body);
lateral (at or near the side of the body, farther from the
midsagittal plane, as opposed to medial); medial (at or near the
middle of the body, at or near the midsagittal plane, as opposed to
lateral); proximal (toward the beginning, at or near the head of
the body, as opposed to distal) and distal (further from the
beginning, at or near the foot of the body, as opposed to
proximal).
[0035] Referring first to FIG. 1, tibial trialing assembly 10
according to one embodiment of the present invention is shown.
Trialing assembly 10 generally includes broaching plate 12 and
trialing plate 14. Referring now to FIGS. 1, 1A and 2, broaching
plate 12 includes an outer periphery shaped to conform to a
resected tibia. The outer periphery includes anterior edge 16 and
opposing posterior edge 18. Broaching plate 12 also includes bottom
surface 22 and opposing top surface 24. Bottom and top surfaces 22,
24 are substantially flat and extend between anterior edge 16 and
posterior edge 18. As is discussed in further detail below,
broaching plate 12 is sized for placement atop a resected tibia.
Accordingly, bottom surface 22 is configured for placement on, and
contact with, the resected tibia. In addition, a portion of
posterior edge 18 curves inward toward anterior edge 16 to form PCL
cutout 20. PCL cutout 20 is configured to accommodate the patient's
posterior cruciate ligament when broaching plate 12 is placed atop
the resected tibia.
[0036] Referring still to FIGS. 1 and 2, broaching plate 12
includes a pair of opposing alignment rails 26, 28 protruding
superiorly from top surface 24. Pair of opposing alignment rails
26, 28 includes anterior rail 26, which extends along a portion of
anterior edge 16. Posterior rail 28 extends along a portion of
posterior edge 18. Particularly, posterior rail 28 extends along
and around PCL cutout 20 of posterior edge 18. Anterior rail 26 and
posterior rail 28 include superior surfaces 26a, 28a,
respectively.
[0037] Referring now to FIG. 2, pin holes 30 extend through
broaching plate 12 from top surface 24 to bottom surface 22. Pin
holes 30 are adapted to receive pins 36 (FIG. 4) or any other
fasteners including screws or nails, as further discussed below.
Broaching plate 12 includes broach receiving opening 32 extending
through broaching plate 12. As discussed in further detail below,
broach receiving opening 32 is sized and configured to allow the
passage of a drill and/or a broach. Alignment openings 34 extend
through broaching plate 12 and are adapted to receive alignment
pegs 64 (FIG. 6) of broach impactor and/or drill guide 60 (FIG. 6),
as is discussed in further detail below.
[0038] Referring to FIGS. 1 and 2, broaching plate 12 includes
anterior tabs 40 protruding anteriorly from anterior edge 16.
Anterior tabs 40 define openings 40a which together with tabs 40
are adapted to engage with a handle (not shown) to facilitate the
positioning of broaching plate 12 on the resected tibia, as
described in U.S. patent application Ser. No. 10/938,979, entitled
Tibial Sizing Apparatus and Method filed Sep. 9, 2004, assigned to
the assignee of the present application and hereby incorporated by
reference. Broaching plate 12 further includes posterior tabs 38
extending posteriorly from posterior edge 18. Posterior tabs 38
define openings 38a, which are configured to receive drop down
screws (not shown). Posterior tabs 38, openings 38a, and drop down
screws cooperate, as described in the above-incorporated U.S.
patent application Ser. No. 10/938,979, to further aid in the
positioning of broaching plate 12 on the resected tibia.
[0039] Broaching plate 12 may be formed of any surgical grade rigid
material. For example, broaching plate 12 may be formed of cobalt
chromium, stainless steel, titanium, and/or alloys thereof.
Broaching plate 12 may be made available in various sizes to
accommodate various sized tibias.
[0040] Turning now to FIGS. 1 and 3, trialing plate 14 includes
substantially flat superior surface 42 and substantially flat,
opposing inferior surface 44. Head receiving openings 46 extend
through trialing plate 14 from superior surface 42 to inferior
surface 44 and are adapted to accommodate head 36a of pins 36 (FIG.
4), as further discussed below.
[0041] Trialing plate 14 includes articular surface provisional
engagement member or boss 48 protruding superiorly from superior
surface 42. As discussed below, boss 48 has an elliptically shaped
cross-section and is configured to engage with an articular surface
provisional. Alternatively, engagement member or boss 48 may have a
variety of shapes and sizes to accommodate engagement with various
designs of surface provisionals. Furthermore, trialing plate may
comprise more than one articular surface provisional engagement
member or boss. Central bore 50 extends in the superior/inferior
direction through boss 48 and trialing plate 14. Bore 50 is adapted
to allow the passage of fastener 54 (FIG. 4), as further discussed
below. Boss 48 is defined by outer perimetrical wall 51, and
includes a trialing plate removal element, which in this embodiment
is in the form of groove 52 cut into wall 51. Similar to broaching
plate 12, trialing plate 14 may be formed of any surgical grade
rigid material. For instance, trialing plate 14 may be formed of
cobalt chromium, titanium, stainless steel and/or alloys
thereof.
[0042] Turning now to FIGS. 1-3 and 5, trialing plate 14 is sized
and configured to removably fit atop broaching plate 12 between
anterior and posterior rails 26, 28. When trialing plate 14 is so
positioned atop broaching plate 12, trialing plate 14 overlies
substantially all of top surface 24 of broaching plate 12. In
addition, as illustrated in FIGS. 1A and 5, when trialing plate 14
is properly positioned atop broaching plate 12, superior surface 42
of trialing plate 14 is substantially level, or flush, with
superior surfaces 26a and 28a of respective anterior and posterior
rails 26, 28 to provide a smooth surface on which the articular
surface provisional can move. As shown in FIGS. 1A and 5, when
trialing plate 14 is positioned atop broaching plate 12, inferior
surface 44 of trialing plate 14 is supported on top surface 24 of
broaching plate 12 such that inferior surface 44 is non-level with
bottom surface 22. Referring specifically to FIG. 5, when
assembled, trialing assembly has height H extending from level
superior surfaces 26a, 28a, 42 to bottom surface 22. Height H is
sized to correspond to the height of the tibial tray of the tibial
implant to be installed.
[0043] Turning now to FIG. 4, use of tibial trialing assembly 10
will now be described. After resecting the patient's tibia T, the
surgeon selects a tibial trialing assembly 10 that most closely
corresponds in size to the proximal surface of tibia T. As noted
above, this trialing assembly 10 will have a width equal to the
tibial tray of the tibial implant the surgeon proposes to use.
Next, broaching plate 12 of trialing assembly 10 is placed on the
resected surface of tibia T. Broaching plate 12 is then secured in
position on tibia T by inserting pins 36 through pin holes 30 of
broaching plate 12 and into tibia T. Heads 36a of pins 36 protrude
superiorly from holes 30 such that pins 36 may be easily removed
later. Referring now to FIGS. 1, 1A and 4, once broaching plate 12
is secured to tibia T, trialing plate 14 is positioned atop
broaching plate 12 between anterior and posterior rails 26, 28. In
this position, head receiving openings 46 of trialing plate 14 are
aligned with pin holes 30 of broaching plate 12. Protruding heads
36a of pins 36 are received in head receiving openings 46 thereby
preventing heads 36a from interfering with the flush placement of
inferior surface 44 of trialing plate 14 against top surface 24 of
broaching plate 12.
[0044] When trialing plate 14 is properly positioned atop broaching
plate 12, trialing plate 14 overlies substantially all of top
surface 24 of broaching plate 12 to provide a smooth,
un-interrupted surface on which the surface provisional may
articulate. Once trialing plate 14 is flushly positioned atop
broaching plate 12, anterior and posterior rails 26, 28 cooperate
to prevent the movement of trialing plate 14 along the plane of top
surface 24 in the medial/lateral and anterior/posterior directions.
Furthermore, as illustrated in FIGS. 1, 1A, 4 and 5, when in
position atop broaching plate 12, superior surface 42 of trialing
plate 14 is level with superior surfaces 26a, 28a of respective
anterior and posterior rails 26, 28. As illustrated in FIGS. 1A and
5, inferior surface 44 of trialing plate 14 is supported by top
surface 24 of broaching plate 12 and, therefore, is spaced apart
from bottom surface 22 of broaching plate 12. Trialing plate 14 may
be secured in position by driving fastener 54 through bore 50 and
into resected tibia T.
[0045] Referring now to FIG. 4, a selected articular surface
provisional (not shown) may now be engaged with boss 48 and
conventional trialing and sizing procedures may be performed. Boss
48 is configured to provide an axis of rotation for trialing
articular surface provisionals modeled after mobile bearing implant
designs. The surgeon may trial several different sized articular
surface provisionals. Once the surgeon has completed the trialing
and sizing procedures and has determined the proper size of bearing
insert, trialing plate 14 is removed by engaging groove 52 of boss
48 with a tool and pulling trialing plate 14 and fastener 54 from
tibia T, exposing broaching plate 12 still aligned and in place on
tibia T. The combined height H of broaching plate 12 and trialing
plate 14 is substantially equivalent to the tibial plate implant
height to mimic the function of the tibial plate during trialing of
a selected surface provisional. However, it should be noted that in
some cases the combined height H need not be equivalent to the
height of the tibial plate. For instance, if the selected articular
surface provisional is configured to have a height (thickness)
greater than that of the articular surface implant, combined height
H may be thinner than the height of the tibial plate. Conversely,
if the selected articular surface provisional is configured to have
a height (thickness) less than that of the articular surface
implant, combined height H may be greater than the height of the
tibial plate. In other words, the combined height of the trialing
assembly and the articular surface provisional is equivalent to the
combined height of the tibial plate implant and the articular
surface implant.
[0046] Turning now to FIG. 6, the surgeon can now prepare the tibia
for receiving the stem of the tibial tray. The surgeon inserts
alignment pegs 64 of drill guide 60 into alignment openings 34.
Drill 62 may then be driven through guide 60, then through broach
opening 32 and into tibia T to create a passage in tibia T for the
acceptance of the stem of the tibial tray. Drill 62 and guide 60
are then removed. Finally, broaching plate 12 is then removed,
leaving the prepared, resected tibia ready to receive the tibial
tray.
[0047] Turning now to FIG. 7, another embodiment is illustrated.
Tibial trialing assembly 110 includes broaching plate 112 and
trialing plate 114. Broaching plate 112 includes all of the
features of broaching plate 12 (FIG. 2) with the addition of
augment holes 141. Trialing plate 114 includes all of the features
of trialing plate 14 (FIG. 3) with the addition of augment holes
142. Augment holes 141 and 142 are adapted to receive an alignment
fastener (not shown) for attaching conventional augment
provisionals to trialing assembly 110. Exemplary augment
provisionals that may be used with broaching plate 112 include
NEXGEN.RTM. augment provisionals by Zimmer, Inc. of Warsaw,
Ind.
[0048] Referring now to FIGS. 8-11, tibial trialing assembly 210
according to another embodiment is illustrated. Tibial trialing
assembly 210 includes broaching plate 212 and trialing plate 214.
As shown in FIGS. 8 and 9, broaching plate 212 includes an outer
periphery shaped to conform to a resected tibia. The outer
periphery includes anterior edge 216 and posterior edge 218. Unlike
broaching plate 12 of trialing assembly 10 (FIG. 1), posterior edge
218 does not include a PCL cut out portion. Broaching plate 212
includes a pair of opposing alignment rails 226, 228 protruding
superiorly from the top surface of broaching plate 212. Pair of
opposing alignment rails 226, 228 includes anterior rail 226, which
extend along a portion of anterior edge 216, and posterior rail
228, which extends along a portion of posterior edge 218. Pin holes
230 extend through broaching plate 212 and are adapted to receive
fasteners (such as pins 36 in FIG. 4) for securing broaching plate
212 to the tibia. Broaching plate 212 also includes broach opening
232, which is sized and configured to allow the passage of a drill
and/or broach.
[0049] Turning now to FIGS. 8, 10 and 11, trialing plate 214 is
substantially flat and is sized to fit over broaching plate 212
between anterior and posterior rails 226, 228. Trialing plate 214
includes superior surface 242 and opposing inferior surface 244.
Pin head receiving openings 246 extend through trialing plate 214
from superior surface 242 to opposing inferior surface 244.
Openings 246 are adapted to accommodate the head of fasteners
received within holes 230 of broaching plate 212. Trialing plate
214 includes engagement member or boss 248 protruding superiorly
from superior surface 242. As noted above, the boss may have a
variety of shapes and sizes. For instance, in the present
embodiment, boss 248 has a circular cross-sectional shape, thereby
demonstrating at least one alternative shape.
[0050] Although the embodiments discussed above show a pair of
opposing anterior and posterior rails, alignment rails could,
alternatively, include any number of rails positioned at any
location along the outer periphery. For instance, the alignment
rails may include two opposing rails, one located at the medial
edge of the outer periphery and the other at the lateral edge of
the outer periphery. In another example, the alignment rails may
include three rails spaced apart along the outer periphery. In
fact, it is possible to have a single rail extending along a
portion of the periphery enough to limit the movement of the
trialing plate when mounted atop the broaching plate. Furthermore,
the alignment rail or rails need not be positioned on the periphery
of the plate. It is also possible to have no alignment rails,
instead using alignment members, such as pegs extending from one of
the trialing plate or broaching plate and mating with alignment
holes in the other of the trialing plate and broaching plate.
Alternatively, the pin heads used to fix the broaching plate to the
tibia could be used in conjunction with the head receiving openings
in the trialing plate to align the trialing plate on the broaching
plate. It should also be noted that the alignment rails could be
alternatively disposed on the inferior surface of the trialing
plate and could engage the outer periphery of the broaching plate
such that broaching plate positioned between the alignment rails of
the trialing plate.
[0051] For example, FIGS. 12-15 illustrate an embodiment having no
alignment rails. Tibial trialing assembly 310 includes broaching
plate 312 and trialing plate 314. Broaching plate 312 includes an
outer periphery shaped to conform to a resected tibia. The outer
periphery includes anterior edge 316 and posterior edge 318.
Broaching plate 312 also includes pin holes 330, which are adapted
to receive fasteners (such as pins 36 in FIG. 4) for securing
broaching plate 312 to the tibia. Broaching plate 312 also includes
broach opening 332, which is sized and configured to allow the
passage of a drill and/or broach. Broaching plate 312 also defines
a pair of peg holes 334.
[0052] Turning to FIGS. 12 and 15, trialing plate 314 is sized and
configured to fit over broaching plate 312 and includes inferior
surface 344 and opposing superior surface 342. Boss 348 protrudes
superiorly from superior surface 342 and is adapted to engage with
trialing surface provisionals. Trialing plate 314 also include pegs
346 extending from inferior surface 344. Pegs 346 are sized and
positioned to align with and extend into peg holes 334 of broaching
plate 312 when trialing plate 314 is seated on broaching plate 312.
Pegs 346 serve to maintain trialing plate's 314 position atop
broaching plate 312 and to prevent trialing plate 314 from sliding
off of broaching plate 312. It should be understood that pegs 346
may be alternatively disposed on the top surface of broaching plate
312, while peg holes 334 may be alternatively disposed in the
inferior surface of trialing plate 314.
[0053] Also, as shown in the embodiments described above, superior
surface of the trialing plate is level with the superior surfaces
of the rails. Alternatively, superior surface 42 of trialing plate
14 may be proud, or raised, with respect to superior surfaces 26a
and 28a of anterior and posterior rails 26, 28 to provide a smooth
surface and to prevent rails 26, 28 from interfering with the
movement of the articular surface provisional.
[0054] Referring to FIGS. 16-19, provisional base plate 412 and
complementary trialing plate 414 according to one embodiment of the
present invention will now be described. Referring specifically to
FIGS. 16 and 17, provisional base plate 412 according to the
present invention is illustrated. Provisional base plate 412 is
adapted to be mounted on the prepared end of the tibia after the
passage has been drilled or broached into the tibia using a
broaching plate as described above. Provisional base plate 412
includes anterior edge 416 and opposing posterior edge 418.
Provisional base plate 412 also includes PCL cut out 420 at
posterior edge 418. Provisional base plate includes opposing
inferior and superior surfaces 422, and 424, respectively, which
extend between anterior and posterior edges 416, 418. Pair of
opposing alignment rails 426, 428 protrudes superiorly from
superior surface 424. Pair of opposing alignment rails 426, 428
includes anterior rail 426, which extends along a portion of
anterior edge 416, and posterior rail 428, which extends along a
portion of posterior edge 418. Notch 427 is formed in anterior rail
426. Provisional base plate 412 also includes stem 430 extending
inferiorly from inferior surface 422. Stem 430 is configured to be
received in the passage, which was created in the tibia as
described above. Stem 430 includes central bore 434 extending
concentrically therein. Bore 434 may be configured to receive a
stem extension (not shown) as needed. Alternatively, bore 434 may
be threaded and adapted to receive an extraction tool, such as a
threaded rod or handle, for extracting provisional base plate 412
from the tibia. Wings or flanges 432 extend radially outward from
stem 430 and serve to aid in anchoring stem 430 in the passage in
the tibia. Provisional base plate 412 may also be equipped with a
magnet operable at superior surface 424 to hold trialing plate 414
in place atop provisional base plate 412.
[0055] Turning now to FIGS. 18 and 19, trialing plate 414 is
illustrated. Trialing plate 414 includes superior surface 442 and
opposing inferior surface 444. Head receiving openings 446 extend
through trialing plate 414 from superior surface 442 to inferior
surface 444. Boss 448 extends upwardly from superior surface 442
and, as suggested above, demonstrates yet another shape and size of
the boss. As illustrated in FIG. 18, boss 448 is curved to provide
limited arc of motion of the articular surface provisional (not
shown) with which boss 448 mates. Accordingly, trialing plate 414
is configured to mimic the surface of a tibial base plate of a knee
implant for use in the left knee. Alternatively, trialing plate 414
could be adapted to mimic the surface of a tibial base plate of
right knee implant by providing a boss having a shape of a
mirror-image to that of boss 448.
[0056] Tab 453 (FIG. 18) extends from an anterior edge of trialing
plate 414 and is configured to mate with notch 427 of provisional
base plate 412, shown in FIG. 16. Trialing plate 414 is
substantially flat and is sized to fit over provisional base plate
412 between anterior and posterior rails 426, 428, such that
superior surface 442 of trialing plate 414 is substantially level
with superior surfaces 426A, 428A of corresponding anterior
posterior rails 426, 428. When trialing plate 414 is positioned
over provisional base plate 412, tab 453 is received in notch 427
to restrict movement of trialing plate 414 in the medial-lateral
direction. Tab 453 also facilitates removal of the trialing plate
from the broaching plate and provisional plate. Anterior and
posterior rails 426, 428 prevent movement of trialing plate 414 in
the anterior-posterior direction. Once trialing plate 414 is
properly positioned atop provisional base plate, an articular
surface provisional (not shown) may now be engaged with boss 448
and conventional trialing and sizing procedures may be
performed.
[0057] Trialing plate 414 is adapted to also mate with broaching
plate 512, shown in FIGS. 20 and 21. Broaching plate 512 includes
an outer periphery shaped to conform to a resected tibia. The outer
periphery includes anterior edge 516 and opposing posterior edge
518. Broaching plate 512 also includes bottom surface 522 and
opposing top surface 524. Bottom and top surfaces 522, 524 are
substantially flat and extend between anterior edge 516 and
posterior edge 518. Broaching plate 512 is sized for placement atop
a resected tibia. Accordingly, bottom surface 522 is configured for
placement on, and contact with, the resected tibia. In addition, a
portion of posterior edge 518 curves inward toward anterior edge
516 to form PCL cutout 520. PCL cutout 520 is configured to
accommodate the patient's posterior cruciate ligament when
broaching plate 512 is placed atop the resected tibia.
[0058] Referring still to FIGS. 20 and 21, broaching plate 512
includes a pair of opposing alignment rails 526, 528 protruding
superiorly from top surface 524. Pair of opposing alignment rails
526, 528 includes anterior rail 526, which extends along a portion
of anterior edge 516, and posterior rail 528, which extends along a
portion of posterior edge 518. Particularly, posterior rail 528
extends along and around PCL cutout 520 of posterior edge 518.
Anterior rail 526 and posterior rail 528 include superior surfaces
526a, 528a, respectively. Pin holes 530 extend through broaching
plate 512 from top surface 524 to bottom surface 522. Pin holes 530
are adapted to receive pins (such as pins 36 shown in FIG. 4) or
any other fasteners including screws or nails, as further discussed
below. Broaching plate 512 includes broach receiving opening 532
extending through broaching plate 512. Broach receiving opening 532
is sized and configured to allow the passage of a drill and/or a
broach. Broaching plate also includes notch 527 formed in anterior
rail 526.
[0059] Broaching plate 512 and trialing plate 414 are used in a
manner similar to that described above with respect to broaching
plate 12 and trialing plate 14. Broaching plate 512 is secured to
the resected surface of the tibia by inserting pins through pin
holes 530. Trialing plate 414 is placed over broaching plate 512
and is positioned between rails 526, 528 such that the heads of the
pins are received in head receiving openings 446 of trialing plate
414 and tab 453 is positioned in notch 527. When so positioned,
superior surface 442 of trialing plate 414 is level with superior
surfaces 526a, 528a of anterior and posterior rails 526, 528. The
assembly of broaching plate 512 and trialing plate 414 may be used
to trial an articular surface provisional in a manner similar to
that described above with respect to tibial trialing assembly
10.
[0060] Although the embodiments shown in the drawings and discussed
above are used in the sizing and trialing of knee implants, it is
contemplated that the present invention could be adapted for use in
sizing and trialing other implants, including elbows and
ankles.
[0061] While this invention has been described as having an
exemplary design, the present invention may be further modified
within the spirit and scope of this disclosure. This application is
therefore intended to cover any variations, uses, or adaptations of
the invention using its general principles. Further, this
application is intended to cover such departures from the present
disclosure as come within known or customary practice in the art to
which this invention pertains.
* * * * *