U.S. patent application number 11/616369 was filed with the patent office on 2008-01-24 for modular orthopaedic component case.
This patent application is currently assigned to ZIMMER TECHNOLOGY, INC.. Invention is credited to Barish Banerjee, Steven L. Meulink, Ryan D. Schlotterback, Stephen J. Vankoski.
Application Number | 20080021567 11/616369 |
Document ID | / |
Family ID | 46328469 |
Filed Date | 2008-01-24 |
United States Patent
Application |
20080021567 |
Kind Code |
A1 |
Meulink; Steven L. ; et
al. |
January 24, 2008 |
MODULAR ORTHOPAEDIC COMPONENT CASE
Abstract
A case for modular neck components for hip implants. The case
may include indicators based on independent variables associated
with physical characteristics of the implant, including leg length,
offset, and anteversion. During surgery, the surgeon may be
confronted with a need to change a preoperatively-chosen modular
neck. For example, the surgeon may desire a change in at least one
of the variables, e.g., leg length, offset, and/or anteversion. The
case allows the surgeon to quickly and easily select a different
modular neck based on an evaluation of one of the variables without
requiring reevaluation of the other variables. A method described
herein may include preoperative planning in which a template
including a grid coordinate system is used, which advantageously
provides an intuitive system for the surgeon both preoperatively
and during surgery.
Inventors: |
Meulink; Steven L.; (Warsaw,
IN) ; Schlotterback; Ryan D.; (Warsaw, IN) ;
Banerjee; Barish; (Kolkata, IN) ; Vankoski; Stephen
J.; (Fort Wayne, IN) |
Correspondence
Address: |
ZIMMER TECHNOLOGY - BAKER & DANIELS
111 EAST WAYNE STREET, SUITE 800
FORT WAYNE
IN
46802
US
|
Assignee: |
ZIMMER TECHNOLOGY, INC.
Warsaw
IN
|
Family ID: |
46328469 |
Appl. No.: |
11/616369 |
Filed: |
December 27, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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11458257 |
Jul 18, 2006 |
|
|
|
11616369 |
|
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Current U.S.
Class: |
623/22.12 |
Current CPC
Class: |
A61F 2/40 20130101; A61F
2/38 20130101; A61F 2002/3625 20130101; A61F 2/0095 20130101; A61F
2002/30332 20130101; A61B 5/4528 20130101; A61F 2002/30616
20130101; A61F 2002/3611 20130101; A61F 2220/0033 20130101; A61B
2050/3008 20160201; A61B 50/33 20160201; A61F 2/46 20130101; A61F
2002/30708 20130101; A61F 2002/365 20130101; A61F 2002/30604
20130101; A61F 2250/0084 20130101; A61B 50/30 20160201; A61B 5/107
20130101; A61F 2002/30963 20130101; A61F 2250/0089 20130101; A61F
2002/4633 20130101; A61F 2002/3071 20130101; A61F 2/3609 20130101;
A61F 2002/30948 20130101; A61F 2002/3652 20130101 |
Class at
Publication: |
623/22.12 |
International
Class: |
A61F 2/32 20060101
A61F002/32 |
Claims
1. A system for facilitating implant selection, the system
comprising: a plurality of implants including at least one subset
in which at least one of a first, second, and third variable
associated with a respective different physical characteristic of
the implants is constant and the others of the first, second, and
third variables vary within each said subset; and at least one case
including a plurality of receptacles, each said receptacle
configured to receive a corresponding one of said plurality of
implants, said plurality of receptacles configured to facilitate
selection of one of said plurality of implants based on a change in
said at least one variable.
2. The system of claim 1, wherein the plurality of implants are
modular components of a hip implant system and the first variable
corresponds to leg length, the second variable corresponds to
offset, and the third variable corresponds to anteversion.
3. The system of claim 1, wherein said plurality of receptacles are
arranged according to each said subset.
4. The system of claim 3, wherein the system includes one said case
per said subset.
5. The system of claim 3, wherein the system includes one said case
with multiple said subsets.
6. The system of claim 3, wherein the system includes a plurality
of cases, each said case including a plurality of receptacles
arranged according to each subset.
7. The system of claim 1, wherein each said implant is sized
slightly smaller than a corresponding said receptacle, wherein each
said implant is positionable in only said corresponding
receptacle.
8. The system of claim 1, wherein said case further includes at
least one removable portion.
9. The system of claim 1, wherein each said receptacle includes an
indicator and each said implant includes an identifier
corresponding to each said indicator.
10. The system of claim 1, wherein said at least one case further
includes at least one template, said template including a grid
coordinate system to assess said at least one variable, said grid
coordinate system having a plurality of reference points
corresponding to at least two of the first, second, and third
variables.
11. The system of claim 1, wherein said at least one case includes
a primary region and a secondary region, at least some of said
plurality of implants positioned in said primary region, said
primary region corresponding to a group of said plurality of
implants primarily utilized.
12. The system of claim 1, wherein said case includes at least one
anatomical structure identifier.
13. The system of claim 12, wherein said case further includes a
first anatomical structure identifier and a second anatomical
structure identifier, said first anatomical structure identifier
configured for use in a first position of said case and said second
anatomical structure identifier configured for use in a second
position of said case, said first position of said case oriented
90.degree. from said second position of said case.
14. The system of claim 1, wherein said case includes a measurement
indicia proximate each said receptacle, each said measurement
indicia corresponding to at least two of said first, second, and
third variables.
15. The system of claim 14, wherein said plurality of implants are
modular components of a hip implant system and the first variable
corresponds to leg length, the second variable corresponds to
offset, and the third variable corresponds to anteversion, said
measurement indicia corresponding to leg length and offset.
16. A system for facilitating implant selection, the system
comprising: a plurality of implants including at least one subset
in which at least one of a first, second, and third variable
associated with a respective different physical characteristic of
the implants is constant and the others of the first, second, and
third variables vary within each said subset; and receptacle means
for receiving each of said plurality of implants and for
facilitating selection of one of said plurality of implants based
on a change in said at least one variable.
17. The system of claim 16, wherein the plurality of implants are
modular components of a hip implant system and the first variable
corresponds to leg length, the second variable corresponds to
offset, and the third variable corresponds to anteversion.
18. The system of claim 16, further comprising indication means for
indicating a corresponding location of each said implant with
respect to said receptacle means.
19. The system of claim 16, further comprising assessment means for
assessing said at least one variable.
20. The system of claim 16, further comprising anatomical
indication means for indicating an anatomical structure associated
with said plurality of implants.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part of co-pending
U.S. patent application Ser. No. 11/458,257, filed Jul. 18, 2006,
entitled METHOD FOR SELECTING MODULAR IMPLANT COMPONENTS, assigned
to the assignee of the present application, the disclosure of which
is hereby expressly incorporated herein by reference.
BACKGROUND
[0002] 1. Field of the Invention
[0003] The present invention relates to modular components for
prosthetic joints. More particularly, the present invention relates
to a case for modular neck components for prosthetic hip
joints.
[0004] 2. Description of the Related Art
[0005] Orthopaedic prosthetic implants are commonly used to replace
some or all of a patient's hip joint in order to restore the use of
the hip joint, or to increase the use of the hip joint, following
deterioration due to aging or illness, or injury due to trauma. In
a hip replacement, or hip arthroplasty procedure, a femoral
component is used to replace a portion of the patient's femur,
including the femoral neck and head. The femoral component is
typically a hip stem, which includes a stem portion positioned
within the prepared femoral canal of the patient's femur and
secured via bone cement, or by a press-fit followed by bony
ingrowth of the surrounding tissue into a porous coating of the
stem portion. The hip stem also includes a neck portion adapted to
receive a prosthetic femoral head. The femoral head may be received
within a prosthetic acetabular component, such as an acetabular cup
received within the prepared recess of the patient's
acetabulum.
[0006] Orthopaedic implants for hip replacement may include modular
hip joint components. For example, the hip stem and the neck
portion with femoral head are formed as separate components. Prior
to an operation, a surgeon chooses a hip stem and a neck portion
based on patient anatomy, body image scans, and/or other
patient-specific data. However, during surgery, the surgeon may
discover that a different hip stem or a different neck portion is
desired to provide more optimum results. Modular hip joint
components allow the surgeon to choose a different hip stem or neck
portion depending on the specific application and needs of the
patient and surgeon. Typically, the surgeon will only change the
neck portion because the hip stem is usually implanted first, and
removal of the hip stem from the femoral intramedullary canal is
generally undesirable. Thus, the neck portion is usually the
component that is most often changed intraoperatively. The surgeon
may be provided with a number of different neck portions to
accommodate various patient anatomies.
[0007] In one known system, for example, the surgeon chooses from a
plurality of options to replace an existing neck portion with an
alternative neck portion to provide the best outcome for the
patient. The surgeon's choices rely on the location of the center
of rotation of the femoral head component of the implant. Referring
to FIG. 1, an image of a proximal femur 20 is shown and includes
femoral head 22, greater trochanter 24, lesser trochanter 26,
femoral neck 28, and a portion of femoral shaft 27. FIG. 1
illustrates a portion 30 of a template used in the known system.
The template may also include images of the femur, similar to those
described below with reference to FIGS. 3 and 4. Portion 30 of the
template may be placed over the image of proximal femur 20 acquired
preoperatively to plan the optimum location of the center of the
femoral head of the implant. Portion 30 of the template may include
a plurality of reference points 32, 34 arranged in a generally
fan-shaped arrangement. Each reference point represents the center
of rotation for the femoral head component of the implant.
Typically, reference points 32, 34 may be based on a spherical or
cylindrical coordinate system. If the surgeon desires an
intra-operative change which differs from the preoperatively chosen
modular neck portion, the surgeon must simultaneously evaluate at
least three variables based on the center of rotation of the
femoral head of the implant, and may need to consult various tables
to evaluate these variables based on physical characteristics of
the patient in order to choose an optimal implant.
SUMMARY
[0008] The present disclosure provides a case for modular neck
components for hip implants. The case may include indicators based
on independent variables associated with physical characteristics
of the implant, including leg length, offset, and anteversion.
During surgery, the surgeon may be confronted with a need to change
a preoperatively-chosen modular neck. For example, the surgeon may
desire a change in at least one of the variables, e.g., leg length,
offset, and/or anteversion. The case allows the surgeon to quickly
and easily select a different modular neck based on an evaluation
of one of the variables without requiring reevaluation of the other
variables. A method described herein may include preoperative
planning in which a template including a grid coordinate system is
used, which advantageously provides an intuitive system for the
surgeon both preoperatively and during surgery.
[0009] In one form thereof, the present disclosure provides a
system for facilitating implant selection, the system including a
plurality of implants including at least one subset in which at
least one of a first, second, and third variable associated with a
respective different physical characteristic of the implants is
constant and the others of the first, second, and third variables
vary within each subset; and at least one case including a
plurality of receptacles, each receptacle configured to receive a
corresponding one of the plurality of implants, the plurality of
receptacles configured to facilitate selection of one of the
plurality of implants based on a change in the at least one
variable.
[0010] In another form thereof, the present disclosure provides a
system for facilitating implant selection, the system including a
plurality of implants including at least one subset in which at
least one of a first, second, and third variable associated with a
respective different physical characteristic of the implants is
constant and the others of the first, second, and third variables
vary within each subset; and receptacle means for receiving each of
the plurality of implants and for facilitating selection of one of
the plurality of implants based on a change in the at least one
variable.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The above-mentioned and other features of the disclosure,
and the manner of attaining them, will become more apparent and
will be better understood by reference to the following description
of embodiments of the disclosure taken in conjunction with the
accompanying drawings, wherein:
[0012] FIG. 1 is an image of a proximal femur, further showing a
portion of a template of a known system overlaid on the image;
[0013] FIG. 2 is a flow chart illustrating steps of a method
according to one embodiment of the present invention;
[0014] FIG. 3 is an image of a template according to one embodiment
of the present invention;
[0015] FIG. 4 is a perspective view of the template of FIG. 3
overlaid over the image of a proximal femur;
[0016] FIG. 5A is a plan view of an exemplary case of modular neck
components used in the method illustrated in FIG. 2;
[0017] FIG. 5B is a plan view of another exemplary case of modular
neck components used in the method illustrated in FIG. 2;
[0018] FIG. 5C is a plan view of yet another exemplary case of
modular neck components used in the method illustrated in FIG.
2;
[0019] FIG. 6 is an exploded view of a modular implant; and
[0020] FIG. 7 is a plan view of an exemplary embodiment case for
modular neck components.
[0021] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplifications set out
herein illustrate embodiments of the disclosure and such
exemplifications are not to be construed as limiting the scope of
the invention in any manner.
DETAILED DESCRIPTION
[0022] Referring to FIG. 2, a flow chart illustrating steps of
method 100 is shown and includes several steps beginning with step
102. Step 102 includes preparing a patient (not shown) for the
surgical procedure, e.g., collecting information and past medical
history. In step 104, the surgeon or a surgeon's assistant will
acquire at least one image of the appropriate portion of the hip
region of the patient, e.g., at least a portion of the femur and
the hip joint. The image may be a radiographic image such as an
X-ray image or fluoroscopic image, for example, or, alternatively,
a computed tomography (CT) image, a magnetic resonance image (MRI),
or any other suitable image. Typical images for a hip replacement
procedure may be taken along two different directions. For example,
anterior/posterior (A/P) and lateral pelvic images may be taken of
the hip joint.
[0023] Referring now to FIG. 3, a template 50 is shown which may be
used in conjunction with the images to preoperatively plan a
surgical procedure in order to perform the joint
replacement/restoration. Template 50 may be constructed of a piece
of transparent plastic or other suitable material which may be
overlaid on the image of the hip portion of the patient. Template
50 may include a plurality of reference points 51 forming a grid
coordinate system, for example, a Cartesian coordinate system,
including a pattern of intersecting horizontal and vertical
indicators or lines that provide coordinates for locating points.
Reference points 51 may be formed of ink deposits on the
transparent plastic, or, alternatively or in combination with the
ink deposits, reference points 51 may be formed as cutouts in the
transparent plastic to allow the surgeon to mark directly on the
acquired image where the ideal center of rotation of the femoral
head of the hip implant should be located. The grid 52 of template
50 may include leg length being measured along the "y-axis" and
offset being measured along the "x-axis." Alternatively, leg length
may be measured along the "x-axis" and offset may be measured along
the "y-axis." Template 50 may also include graphic representations
of a femoral stem component of hip implant 40 (FIG. 6), i.e., stem
46 (FIG. 6), including recess 48 shown in dashed lines in FIGS. 3
and 6. The representation of stem 46 may be formed of conventional
ink on the transparent plastic. A plurality or system of templates
50 may be provided corresponding to each available size or type of
femoral stem component of the hip implant system.
[0024] As shown in FIG. 3, template 50 may also include reference
points 54 corresponding to the lateral pelvic view of the hip
portion of the patient and which represent a third axial or
cylindrical component corresponding to the anteversion component of
the hip implant. Reference points 54, which are arranged in three
planes, may represent an anteverted neck, a straight neck, or a
retroverted neck. The planes of reference points 54 may represent
the "z-axis" of grid 52 in the Cartesian coordinate system, or,
alternatively, the third component may be represented in a
cylindrical or polar coordinate system in which, when viewed from
an end view of the proximal end of the femur, the planes in which
reference points 54 are situated are arranged in a fan-shaped
arrangement. More or less planes of reference points 54 may be
included to accommodate a greater number of anteversion components,
if needed.
[0025] In step 106, the surgeon selects the template 50
corresponding to the femoral stem component of the hip implant to
be used in the surgical procedure. Template 50 may be chosen in a
conventional manner such that the representation of stem 46 on
template 50 substantially fills the intramedullary canal of femoral
shaft 27 of the image, such that the actual femoral stem component
of the hip implant will correctly fit the intramedullary canal of
the actual femur.
[0026] In step 108 and as shown in FIG. 4, the surgeon superimposes
the correct template 50 on the acquired image. In step 110,
template 50 may be used by the surgeon to determine the desired leg
length and offset when using portion 50a of template 50
corresponding to the A/P pelvic view and to determine the desired
anteversion and/or leg length when using portion 50b of template 50
corresponding to the lateral pelvic view. For the purposes of this
document, offset is measured along a line drawn substantially
perpendicular to longitudinal axis 41 of femoral stem 46. The
surgeon orients the representation of stem 46 on template 50 to
align with the intramedullary canal of the image of femoral shaft
27. When the surgeon is using portion 50a of template 50
corresponding to the A/P pelvic view, the surgeon orients origin 53
of grid 52 at the location at which the surgeon desires center 49
of head 42 of modular neck 44 (FIG. 6) to be located. This location
of center 49 may not necessarily coincide with the original center
of femoral head 22 prior to surgery because the condition of
femoral head 22 may dictate a different center for the head of the
modular implant component. For example, if the original femoral
head 22 is severely deteriorated or is badly misshapen, the surgeon
may desire a different center for the head of the modular implant
than the current center for the original femoral head 22. Also, the
surgeon may wish to correct some problem, e.g., laxity correction
or bone alignment correction, which may cause the center for the
head of the modular implant to be different than the center of
femoral head 22. In an exemplary procedure, origin 53 coincides
with center 49, as shown in FIG. 4. The surgeon then assesses or
evaluates where center 49 should be located on grid 52 of template
50. This evaluation permits the surgeon to obtain the
preoperatively-planned values for the offset and the leg length for
the modular neck component of the hip implant.
[0027] Still referring to step 110 and FIG. 4, when the surgeon is
using portion 50b of template 50 corresponding to the lateral
pelvic view, the surgeon chooses a desired anteversion component
from the planes of reference points 54. The surgeon again orients
the representation of stem 46 on template 50 to align with the
intramedullary canal of the image of femoral shaft 27, in the
manner described above. The surgeon may use the planes of reference
points 54 to determine the desired anteversion component for the
modular neck of the hip implant. In an exemplary procedure, the
surgeon will determine the anteversion component first, and then
determine the necessary leg length and offset values for the
preoperative plan of the procedure.
[0028] In step 110, the surgeon may mark directly on the image
where center 49 of head 42 of modular neck 44 (FIG. 6) will be
located and/or what anteversion component is necessary. In step
112, the surgeon then selects a modular neck 44 from system 60
(FIGS. 5A-5C) corresponding to the assessed variables of leg
length, offset, and anteversion in the manner described below.
[0029] Alternatively, template 50 may be a template on a computer
screen in a computer assisted surgery (CAS) system. The surgeon may
superimpose the computer generated template 50 in the CAS system on
the image of the proximal femur to determine the optimal position
of center 49 of head 42 of a modular neck 44 (FIG. 6). In one such
embodiment, advantageously, both views, i.e., A/P and lateral, may
be simultaneously viewed in the CAS system and template 50 may be
superimposed thereon to allow the surgeon to simultaneously assess
all three variables, i.e., anteversion, leg length, and offset.
[0030] During surgery and as shown in step 114, a
preoperatively-chosen femoral stem 46 of hip implant 40 (FIG. 6) is
implanted into a patient's prepared intramedullary canal by a
conventional surgical technique. The surgeon may then provisionally
implant the preoperatively-chosen modular neck 44 (FIG. 6) which
has been chosen by the surgeon to provide the optimum result for
the particular patient, in the manner described above. Modular neck
44 (FIG. 6) may include head 42, neck portion 43, and tapered
portion 47 shaped to mate with recess 48 in femoral stem 46. Head
42 may be integrally formed with neck 44 or head 42 may be a
modular component attached to neck portion 43 of neck 44.
Advantageously, the femoral stem 46 (FIG. 6) of hip implant 40
(FIG. 6) is equipped to accept a number of different modular neck
components. Thus, the leg length, anteversion, and offset of the
hip implant can be changed without requiring removal of femoral
stem 46.
[0031] In step 116, the surgeon may trial the provisionally
implanted modular neck 44 (FIG. 6) to verify or confirm the
preoperative plan and associated results. At this point, the
surgeon will assess several variables, for example, leg length,
offset, and anteversion, associated with the hip implant and the
physical anatomy of the patient. This assessment may be completed
via a conventional surgical technique, for example, moving the
joint through a range of motion. The surgeon may observe that more
leg length is necessary, but that the offset and anteversion are
satisfactory. The present method advantageously allows the surgeon
to select a new modular neck based only on the change in leg length
without affecting the offset and anteversion. Similarly, the
surgeon may observe that more offset is necessary, but that the leg
length and anteversion are satisfactory. The present method
advantageously allows the surgeon to select a new modular neck
based only on the change in offset without affecting the leg length
and anteversion. Because the leg length and offset changes are
based on a grid coordinate system, the surgeon can easily and
intuitively select a new modular neck component based on a leg
length change and/or an offset change without requiring an
extensive lookup table or complicated mathematical conversion
calculations to ensure that no other variables are being changed
undesirably.
[0032] Similarly, the surgeon may observe that a different
anteversion component is necessary, but that the leg length and
offset are satisfactory. The present method advantageously allows
the surgeon to select a new modular neck based only on the change
in anteversion without affecting the leg length and offset. Because
the anteversion component is based on a grid coordinate system,
similar to leg length and offset, described above, or,
alternatively, on a polar coordinate system, the surgeon can easily
and intuitively select a new modular neck component based on a
change in anteversion without requiring an extensive lookup table
or complicated mathematical conversion calculations to ensure that
no other variables are being changed undesirably.
[0033] After the surgeon determines the desired change, the surgeon
may employ system 60 (FIGS. 5A-5C), described below, to choose a
different modular neck 44 to provide more optimum results.
[0034] Referring now to FIGS. 5A-5C, system 60 is arranged to
include a plurality of modular necks 44 with varying dimensions
suitable for different leg length, offset, and anteversion
dimensions. In one embodiment, system 60 may include container 61
with a plurality of compartments 63 for physically housing each
modular neck 44 in system 60, wherein each modular neck 44 is held
in respective compartments 63 and the surgeon or an assistant
selects a modular neck 44 from a compartment 63 in container 61.
Each neck 44 may include reference identifier 69. In an alternative
embodiment, system 60 may be a graphical representation of the
plurality of modular necks 44 arranged in an organized arrangement,
e.g., a Cartesian coordinate system. In this embodiment, the
surgeon may select a modular neck 44 and corresponding reference
identifier 69, for example, from the graphical representation, and
reference identifier 69 may then be used by a surgical assistant,
for example, to retrieve the desired modular neck 44 which
corresponds to the surgeon's desired choice and reference
identifier 69 from a central location at which the modular necks 44
are stored.
[0035] A subset of system 60 may be provided and arranged in
container or case 61. Alternatively, a plurality of subsets of
system 60 may be provided and arranged in at least one container
61. System 60 is arranged such that all necks 44 within a given
subset of necks correspond to a particular anteversion component.
Each subset may have a different anteversion component, thereby
permitting a surgeon to independently assess the desired
anteversion component and have an identical subset of necks 44 for
each anteversion component. For example, the anteversion component
may be, for example, anteverted, straight, or retroverted. Thus,
for example, referring to FIG. 5A, subset 60a of necks 44 in system
60 may correspond to straight necks. Referring to FIG. 5B, subset
60b of necks 44 in system 60 may correspond to anteverted necks.
Similarly, referring to FIG. 5C, subset 60c of necks 44 in system
60 may correspond to retroverted necks. System 60 may include as
many subsets of necks 44 that correspond to the desired number of
choices of the anteversion component, for example, system 60 may
include additional subsets corresponding to greater extremes of
anteverted and retroverted necks.
[0036] Still referring to FIGS. 5A-5C, for each neck 44 in each
subset 60a, 60b, 60c of system 60, system 60 includes a pair of
identifying coordinates corresponding to leg length and offset. For
example, the number represented by offset component 62 corresponds
to offset and the number represented by leg length component 64
corresponds to leg length. The Cartesian coordinates represented by
offset component 62 and leg length component 64 may be represented
by the following coordinates: (.+-.offset, .+-.leg length). If
origin 53 does coincide with center 49 during the preoperative
planning, then the surgeon may likely choose a modular neck 44 with
the following coordinates in step 112: (+0, +0). If origin 53 does
not coincide with center 49 during the preoperative planning due
to, for example, a defect in femoral head 22, then the surgeon may
choose a modular neck with coordinates different from (+0, +0) in
step 112.
[0037] Each subset 60a, 60b, 60c may include two sets of pairs of
identifying coordinates corresponding to leg length and offset.
Each set corresponds to either a right hip or a left hip.
Advantageously, as shown in FIGS. 5A-5C, the surgeon need only
rotate container 61 ninety degrees to switch between a system used
for the left hip and the right hip. For example, as shown in FIG.
5A, the left hip pair of coordinates is identified by the letter L
and the right hip pair of coordinates is identified by the letter
R. Furthermore, as identified at the top of container 61, the
anteversion component includes a designation "right" or "left"
depending on which hip those necks 44 are to be used for. For
example, if the surgeon needs a straight neck for a left hip, then
the surgeon rotates container 61 including subset 60a until "LEFT
STRAIGHT" appears at the top of container 61, as shown in FIG. 5A,
at which point the offset and leg length coordinates are positioned
below each respective neck 44. Alternatively, the offset and leg
length coordinates may be positioned above each respective neck
44.
[0038] Intraoperatively, if the surgeon does not want any change in
offset but needs a change in leg length, the surgeon will choose a
new neck 44 having the following coordinates:
(preoperatively-planned offset value, preoperatively-planned leg
length value.+-.change in leg length) from a particular subset
according to the chosen anteversion component. Similarly, if the
surgeon does not want any change in leg length but needs a change
in offset, the surgeon will choose a neck 44 having the following
coordinates: (preoperatively-planned offset value.+-.change in
offset, preoperatively-planned leg length value) from a particular
subset according to the chosen anteversion component.
[0039] Advantageously, arranging the plurality of modular necks 44
in each subset 60a, 60b, 60c of system 60 in a Cartesian coordinate
grid allows the surgeon to easily and intuitively intraoperatively
choose a modular neck 44 which corresponds to an independent change
in leg length, offset, or anteversion. The surgeon may use a
fluoroscopic or other image-guided system (not shown) to facilitate
the assessment of the change in leg length, offset, and/or
anteversion, as described above, or, alternatively, the surgeon may
simply manually/visually determine the desired change in leg
length, offset, and/or anteversion, and subsequently choose a neck
44 from a subset of system 60 corresponding to the desired
change.
[0040] In one example, if the surgeon determines in step 116 that
more or less leg length is desired but that the offset and
anteversion are satisfactory, the surgeon may select a different
modular neck 44 from a subset of system 60 which corresponds to the
desired change. For example, if the surgeon needs no change in
offset and 4 millimeters (mm) more of leg length, the surgeon
chooses the neck with the following coordinates from a subset of
system 60 corresponding to the satisfactory anteversion component:
(preoperatively-planned offset value, preoperatively-planned leg
length value plus 4). Subsequently, the surgeon implants neck 44
into the femoral stem component of the hip implant. The surgeon may
similarly choose a different neck 44 depending on how much change
in leg length was desired.
[0041] In another example, if the surgeon determines in step 116
that less leg length and more offset are desired but the
anteversion is satisfactory, the surgeon may select a different
modular neck 44 from a subset of system 60 which corresponds to the
desired change. For example, if the surgeon needs 4 mm more of
offset and 4 mm less of leg length, the surgeon chooses the neck
with the following coordinates from a subset of system 60
corresponding to the satisfactory anteversion component:
(preoperatively-planned offset value plus 4, preoperatively-planned
leg length value minus 4). Subsequently, the surgeon implants neck
44 into the femoral stem component of the hip implant. The surgeon
may similarly choose a different neck 44 depending on how much
change in leg length and/or offset was desired.
[0042] In yet another example, if the surgeon determines in step
116 that leg length and offset are satisfactory but the anteversion
needs changed, the surgeon may select a different modular neck 44
from a subset of system 60 which corresponds to the desired change.
For example, if the surgeon needs to change from a retroverted neck
to a straight neck, the surgeon will select neck 44 from subset 60a
of system 60 corresponding to a straight neck and having the
desired leg length and offset.
[0043] In step 118, the different neck 44 chosen by the assessment
of leg length, offset, and anteversion in step 116 is implanted
into the stem component of the hip implant.
[0044] Referring now to FIG. 7, another exemplary embodiment of a
container of system 60 is shown. Container 61' is substantially
similar to container 61, described above with reference to FIGS.
5A, 5B, and 5C, except as described below. Container 61' may
include a plurality of compartments 63 for physically housing each
modular neck 44 in system 60. Each compartment 63 may be slightly
larger than a corresponding modular neck 44 such that compartments
63 form tight tolerances with a corresponding modular neck 44. In
this manner, each modular neck 44 may only be positioned in the
corresponding correct compartment 63, i.e., modular neck 44
designated "N" may only be positioned in compartment 63 designated
"N". Each compartment 63 includes indicator 70 which may be etched
into container 61' inside compartment 63. In each compartment 63,
indicator 70 matches reference identifier 69 for the corresponding
modular neck 44 to be positioned in that compartment 63.
[0045] Still referring to FIG. 7, container 61' may also include
template 50' etched in at least one corner thereof. Template 50'
may be a miniaturized version of template 50 (FIGS. 3 and 4) to
assist a surgeon or surgical assistant during a surgical procedure.
Template 50' may depict a left hip joint prosthesis when etched
next to the "LEFT STRAIGHT" designation on container 61' and,
similarly, template 50' may depict a right hip joint prosthesis
when etched next to the "RIGHT STRAIGHT" designation on container
61'. Alternatively, template 50' may be adhesively attached to
container 61' or carved therein. As shown in FIG. 7, container 61'
is in a first position in which a surgeon or surgical assistant may
use container 61' with a surgical procedure on the left hip.
Container 61' may be rotated 90.degree. in the general direction of
Arrow A such that container 61' is in a second position in which a
surgeon or surgical assistant may use container 61' with a surgical
procedure on the right hip.
[0046] Container 61' may also be divided into secondary region 78
and primary region 76 which are divided by boundary 80. Primary
region 76 may include a color, pattern, or other identifying
structure on container 61' such as to identify a range of modular
necks 44 which are most often used in a surgical procedure.
Secondary region 78 identifies a range of modular necks 44 which
are less often used in a surgical procedure. Each container 61' for
subsets 60a, 60b, and 60c (FIGS. 5A, 5B, and 5C, respectively) may
have a different color or other identifying structure to facilitate
use with a surgical procedure.
[0047] Container 61' may also include a plurality of removable
portions or trays 72. Each removable tray 72 may be positioned in a
corresponding recess 74 in container 61'. Removable tray 72 may
include one or more modular necks 44 which may be less often used
in a surgical procedure. Removable trays 72 may be snap-fit into
engagement with recess 74 when necessary. If the modular necks 44
in removable trays 72 are not necessary, container 61' may be used
without trays 72 positioned therein.
[0048] Although illustrated throughout as having intervals of 4 mm
for both offset and leg length, system 60 could be arranged to have
intervals of any dimension to accommodate the needs of a particular
patient or the desires of a particular surgeon. For example, the
interval could be 1, 2, 3, 4, or 5 mm, or any fraction thereof, for
both offset and leg length.
[0049] The above-described concept has generally been described as
a system having three variables, i.e., leg length, offset, and
anteversion. The system has been described in which one of these
three variables, i.e., the anteversion component, is constant for
any given subset of implants having various offsets and leg
lengths. For example, the surgeon may pre-operatively choose a
desired anteversion component, which may not change
intraoperatively, and then need only choose various modular necks
44 from the subset corresponding to the desired anteversion
component of system 60 based only on offset and leg length.
Alternatively, the system may be constructed such that leg length
is the constant variable and the implants of each subset of system
60 are arranged to have identical leg lengths and varying offset
and anteversion components. In another alternative embodiment, the
system may be constructed such that offset is the constant variable
and the implants of each subset of system 60 are arranged to have
identical offsets and varying leg lengths and anteversion
components.
[0050] Although described throughout with respect to a hip implant,
the method could be utilized in any procedure which uses modular
components, for example, but not limited to, shoulder implant
procedures, knee implant procedures, etc.
[0051] While this disclosure has been described as having exemplary
designs, the present disclosure can 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
disclosure 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
disclosure pertains and which fall within the limits of the
appended claims.
* * * * *