U.S. patent application number 15/224741 was filed with the patent office on 2016-11-24 for patient-specific tools and implants.
The applicant listed for this patent is Biomet Manufacturing, LLC. Invention is credited to Jason D. Meridew, Robert Metzger, John R. White.
Application Number | 20160338838 15/224741 |
Document ID | / |
Family ID | 49914650 |
Filed Date | 2016-11-24 |
United States Patent
Application |
20160338838 |
Kind Code |
A1 |
Meridew; Jason D. ; et
al. |
November 24, 2016 |
PATIENT-SPECIFIC TOOLS AND IMPLANTS
Abstract
A method for preparing a femoral neck for receiving a neck
implant includes resecting a femoral head from a femoral neck of a
patient according to a pre-operative patient-specific plan. The
method also includes removing only cancellous bone from the femoral
neck and proximal femoral bone of the patient using a
patient-specific broach. The patient-specific broach has a
three-dimensional cutting surface matching as a negative mold a
cortical/cancellous bone interface surface of the femoral neck of
the patient.
Inventors: |
Meridew; Jason D.; (Warsaw,
IN) ; White; John R.; (Winona Lake, IN) ;
Metzger; Robert; (Wakarusa, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Biomet Manufacturing, LLC |
Warsaw |
IN |
US |
|
|
Family ID: |
49914650 |
Appl. No.: |
15/224741 |
Filed: |
August 1, 2016 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14027340 |
Sep 16, 2013 |
9445907 |
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15224741 |
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13041665 |
Mar 7, 2011 |
8535387 |
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14027340 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61B 17/809 20130101;
A61F 2/3609 20130101; A61F 2002/30617 20130101; Y10T 29/49826
20150115; A61B 2034/105 20160201; B33Y 70/00 20141201; A61F 2/30942
20130101; A61F 2/3601 20130101; A61B 34/10 20160201; A61F 2250/0097
20130101; A61B 17/1659 20130101; A61B 2034/108 20160201; B33Y 80/00
20141201; A61F 2002/30593 20130101; A61B 17/164 20130101; A61F
2002/30574 20130101; A61B 17/1668 20130101; A61B 17/1624
20130101 |
International
Class: |
A61F 2/36 20060101
A61F002/36 |
Claims
1-20. (canceled)
21. A femoral neck implant comprising: a body for implantation into
a femoral neck of a patient, the body having a patient-specific
cross-section of variable size and shape along a longitudinal axis
of the body and a patient-specific three-dimensional outer surface
that nests and conforms complementarily to a cortical boundary
surface corresponding to a cortical/cancellous bone interface
surface of the femoral neck of the specific patient after removing
only the cancellous bone from the femoral neck; and a neck portion
extending from the body and configured for coupling with a femoral
head implant.
22. The femoral neck implant of claim 21, wherein the neck portion
is configured to be aligned along a patient-specific articulation
axis.
23. The femoral neck implant of claim 21, further comprising a
flange coupled to the body and configured for abutting a resected
surface of the femoral neck of the specific patient.
24. The femoral neck implant of claim 21, wherein the body is sized
to extend only into the femoral neck of the specific patient and
has a patient-specific length.
25. The femoral neck implant of claim 21, wherein the femoral head
implant is coupled to the neck portion and has a patient-specific
shape.
26. The femoral neck implant of claim 21, in further combination
with a femoral neck cutting tool comprising: a body having a
patient-specific cross-section of variable size and shape along a
longitudinal axis and a patient-specific three-dimensional outer
cutting surface that nests and conforms complementarily to the
cortical boundary surface corresponding to the cortical/cancellous
bone interface surface of the femoral neck of the specific patient,
wherein the body is configured for removing only the cancellous
bone from the femoral neck of the specific patient to facilitate
implantation of the femoral neck implant.
27. The femoral neck implant of claim 21, in further combination
with a patient-specific guide for preparing the femoral neck of the
specific patient for receiving the femoral neck implant, the guide
comprising: a first wall having a first inner surface with a
patient-specific inner bore therethrough, wherein the first inner
surface is configured to mate with a resected surface of the
femoral neck, wherein the patient-specific inner bore is configured
for guiding a cutting tool to remove only the cancellous bone from
the femoral neck to the cortical boundary surface corresponding to
the cortical/cancellous bone interface surface of the femoral neck
for receiving the femoral neck implant; and a peripheral wall
extending from the first wall, wherein the peripheral wall includes
a three-dimensional patient-specific peripheral inner surface
configured to mate in only one position with an outer peripheral
surface of the femoral neck after resection by the cutting
tool.
28. A patient-specific guide for preparing a femoral neck of a
patient for receiving a femoral neck implant comprising: a first
wall having a first inner surface with a patient-specific inner
bore therethrough, wherein the first inner surface is configured to
mate with a resected surface of the femoral neck, wherein the
patient-specific inner bore is configured for guiding a cutting
tool to remove only a cancellous bone from the femoral neck to a
cortical boundary surface corresponding to a cortical/cancellous
bone interface surface of the femoral neck of a specific patient;
and a peripheral wall extending from the first wall, wherein the
peripheral wall includes a three-dimensional patient-specific
peripheral inner surface configured to mate in only one position
with an outer peripheral surface of the femoral neck after
resection by the cutting tool.
29. The patient-specific guide of claim 28, in further combination
with the cutting tool which includes a body having a
patient-specific cross-section of variable size and shape along a
longitudinal axis and a patient-specific three-dimensional outer
cutting surface that nests and conforms complementarily to the
cortical boundary surface corresponding to the cortical/cancellous
bone interface surface of the femoral neck of the specific patient,
wherein the body is configured for removing only the cancellous
bone from the femoral neck of the specific patient.
30. The patient-specific guide of claim 28, in further combination
with the patient-specific femoral neck implant, the femoral neck
implant comprising: a body for implantation into a femoral neck of
a patient, the body having a patient-specific cross-section of
variable size and shape along a longitudinal axis of the body and a
patient-specific three-dimensional outer surface that nests and
conforms complementarily to the resected surface corresponding to
the cortical boundary surface at the cortical/cancellous bone
interface surface of the femoral neck of the specific patient; and
a neck portion extending from the body and configured for coupling
with a femoral head implant.
31. A femoral neck cutting tool comprising: a body having a
patient-specific cross-section of variable size and shape along a
longitudinal axis and a patient-specific three-dimensional outer
cutting surface that closely nests and conforms complementarily to
a cortical boundary surface corresponding to a cortical/cancellous
bone interface surface of a femoral neck of the specific patient
and configured for removing only the cancellous bone from the
femoral neck of the patient; and a non patient-specific coupling
component for engaging a non patent-specific driver tool.
32. The cutting tool of claim 31, wherein the coupling component
includes a protrusion extending from a proximal surface of the
cutting tool and a bore defined through the proximal surface of the
cutting tool.
33. The cutting tool of claim 32, in combination with a driver tool
having a distal surface with a driver tool bore for receiving the
protrusion and a retractable rod having a distal portion insertable
into the bore of the cutting tool for holding the cutting tool.
34. The cutting tool of claim 31, in further combination with a
patient-specific guide for preparing the femoral neck of the
specific patient, the guide comprising: a first wall having a first
inner surface with a patient-specific inner bore therethrough,
wherein the first inner surface is configured to mate with a
resected surface of the femoral neck, wherein the patient-specific
inner bore is configured for guiding the cutting tool to remove
only the cancellous bone from the femoral neck to the cortical
boundary surface corresponding to the cortical/cancellous bone
interface surface of the femoral neck for receiving a femoral neck
implant; and a peripheral wall extending from the first wall,
wherein the peripheral wall includes a three-dimensional
patient-specific peripheral inner surface configured to mate in
only one position with an outer peripheral surface of the femoral
neck after resection.
35. The cutting tool of claim 31, in further combination with a
patient-specific neck implant having a body with a patient-specific
cross-section of variable size and shape along a longitudinal axis
of the body and a patient-specific three-dimensional outer surface
that nests and conforms complementarily to the resected surface
which corresponds to cortical boundary surface at the
cortical/cancellous bone interface surface of the femoral neck of
the specific patient after removal of only the cancellous bone from
the femoral neck.
36. A system for preparing a femoral neck of a specific patient
comprising: a cutting tool having a patient-specific cross-section
of variable size and shape along a longitudinal axis and a
patient-specific three-dimensional outer cutting surface that nests
and conforms complementarily to a cortical boundary surface
corresponding to a cortical/cancellous bone interface surface of
the femoral neck of the specific patient, wherein the cutting tool
is configured for removing only a cancellous bone from the femoral
neck of the specific patient to create a resected surface; and a
femoral neck implant for implantation into the femoral neck of a
patient, the femoral neck implant having a body with a
patient-specific cross-section of variable size and shape along a
longitudinal axis of the body and a patient-specific
three-dimensional outer surface that nests and conforms
complementarily to the resected surface which corresponds to
cortical boundary surface at the cortical/cancellous bone interface
surface of the femoral neck of the specific patient after removal
of only the cancellous bone from the femoral neck.
37. The system of claim 36, in further combination with a
patient-specific guide comprising: a first wall having a first
inner surface with a patient-specific inner bore therethrough,
wherein the first inner surface is configured to mate with the
resected surface; and a peripheral wall extending from the first
wall, wherein the peripheral wall includes a three-dimensional
patient-specific peripheral inner surface configured to mate in
only one position with an outer peripheral surface of the femoral
neck after resection.
38. The system of claim 36, wherein the femoral neck implant
further includes a neck portion extending from the body, the neck
portion is configured to be aligned along a patient-specific
articulation axis.
39. The system of claim 36, wherein the femoral neck implant
further includes a flange coupled to the body and configured for
abutting the resected surface of the femoral neck of the specific
patient.
40. The system of claim 36, wherein the body of the femoral neck is
sized to extend only into the femoral neck of the specific patient
and has a patient-specific length.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 13/041,665 filed on Mar. 7, 2011.
[0002] The disclosure of the above application is incorporated
herein by reference.
INTRODUCTION
[0003] The present teachings provide a bone-preserving design for a
hip prosthesis. More specifically, the present teachings are
directed to patient-specific femoral neck implants and associated
tools and methods
SUMMARY
[0004] The present teachings provide various methods, tools and
implants for preparing a femoral neck to receive a neck
implant.
[0005] The present teachings provide a method for preparing a
femoral neck for receiving a neck implant. The method includes
obtaining image data of a proximal femoral bone and femoral neck of
a patient by a medical imaging method and constructing a
three-dimensional image model of the proximal femoral bone and neck
of the patient using the image data. The method further includes
identifying a three-dimensional cortical boundary surface at an
interface between cortical and cancellous bone of the patient using
the image model. A patient-specific broach having a
three-dimensional cutting surface closely matching and
complementary to the cortical boundary surface of the patient using
the image model is designed and manufactured.
[0006] Another method according to the present teachings includes
resecting a femoral head from a femoral neck of a patient according
to a pre-operative patient-specific plan. The method further
includes removing only cancellous bone from the femoral neck and
proximal femoral bone of the patient using a patient-specific
broach having a three-dimensional cutting surface closely matching
and complementary to a cortical/cancellous bone interface surface
of the femoral neck of the patient.
[0007] The present teachings provide a femoral neck implant. The
femoral neck implant includes a body for implantation into a
femoral neck of a patient. The body has a patient-specific
cross-section of variable size and shape along a longitudinal axis
of the body and a patient-specific three-dimensional outer surface
that closely nests and conforms complementarily to a cortical
boundary surface corresponding to a cortical/cancellous bone
interface surface of the femoral neck of the specific patient after
removing only the cancellous bone from the femoral neck. The neck
implant can include a neck portion extending from the body and
configured for coupling with a femoral head implant.
[0008] The present teachings provide a femoral neck cutting tool,
such as a broach for preparing a femoral neck for a femoral neck
implant. The cutting tool includes a body having a patient-specific
cross-section of variable size and shape along a longitudinal axis
and a patient-specific three-dimensional outer cutting surface that
closely nests and conforms complementarily to a cortical boundary
surface corresponding to a cortical/cancellous bone interface
surface of a femoral neck of the specific patient and configured
for removing only the cancellous bone from the femoral neck of the
patient. The cutting tool can include a non patient-specific
coupling component for engaging a non patent-specific driver
tool.
[0009] The present teachings also provide a patient-specific guide
for preparing a femoral neck of a patient for receiving a femoral
neck implant. The patient-specific guide includes a first wall
having a first inner surface with a patient-specific inner bore
therethrough, and a peripheral wall extending from the first wall.
The first inner surface is configured to mate with a resected
surface of the femoral neck. The peripheral wall includes a
three-dimensional patient-specific peripheral inner surface
configured to mate in only one position with an outer peripheral
surface of the femoral neck after resection.
[0010] Further areas of applicability of the present teachings will
become apparent from the description provided hereinafter. It
should be understood that the description and specific examples are
intended for purposes of illustration only and are not intended to
limit the scope of the present teachings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The present teachings will become more fully understood from
the detailed description and the accompanying drawings,
wherein:
[0012] FIG. 1 is a perspective view of a patient-specific neck
implant according to the present teachings;
[0013] FIG. 1A is a perspective view of a patient-specific neck
implant according to the present teachings;
[0014] FIG. 2 is an environmental view of the neck implant of FIG.
1;
[0015] FIG. 3 is a plan view of the proximal femur showing a
resection of the femoral neck at a plane C;
[0016] FIG. 4 is an environmental view showing a patient-specific
broach for the femoral neck implant;
[0017] FIG. 5 is a perspective view of a patient-specific broach
according to the present teachings;
[0018] FIG. 6 is a plan view of a driver tool for the broach of
FIG. 5;
[0019] FIG. 7 is a plan view of the driver tool of FIG. 6 coupled
to the broach of FIG. 5;
[0020] FIG. 8 is a flow chart of a method according to the present
teachings;
[0021] FIG. 9 is a flow chart of a method according to the present
teachings;
[0022] FIG. 10 is an exploded environmental view of a
patient-specific cutting guide for a neck implant according to the
present teachings; and
[0023] FIG. 10A is an environmental view of the cutting guide of
FIG. 10.
DESCRIPTION OF VARIOUS EMBODIMENTS
[0024] The following description is merely exemplary in nature and
is in no way intended to limit the present teachings, applications,
or uses.
[0025] The present teachings provide patient-specific tools and
implants designed for a conservative hip procedure that conserves a
portion of femoral neck of a specific patient.
[0026] As described in commonly assigned U.S. application Ser. No.
11/756,057, filed on May 31, 2007, during a preoperative planning,
imaging data of the relevant anatomy of a patient can be obtained
at a medical facility or doctor's office. The imaging data can
include, for example, a detailed scan of a pelvis, hip, knee, ankle
or other joint or relevant portion of the patient's anatomy. The
imaging data can be obtained using MRI, CT, X-Ray, ultrasound or
any other imaging system. The imaging data obtained can be used to
construct a three-dimensional computer image of the joint and
prepare an initial pre-operative plan that can include bone or
joint preparation, including planning for resections, milling,
reaming, broaching, implant selection and fitting, design of
patient-specific guides, templates, tools and alignment protocol
for the surgical procedure.
[0027] Computer modeling for obtaining three-dimensional computer
images of the relevant patient's anatomy can be provided by various
CAD programs and/or software available from various vendors or
developers, such as, for example, from Materialise USA, Plymouth,
Mich. The computer modeling program can be used to plan a
preoperative surgical plan, including planning various bone
preparation procedures, selecting or designing/modifying implants
and designing patient-specific guides and tools including
patient-specific prosthesis components, and patient-specific tools,
including reaming, broaching, milling, drilling or cutting tools,
alignment guides, templates and other patient-specific
instruments.
[0028] The pre-operative plan can be stored in any computer storage
medium, in a computer file form or any other computer or digital
representation. The pre-operative plan, in a digital form
associated with interactive software, can be made available via a
hard medium, a web-based or mobile or cloud service, a cellular
portable device to the surgeon or other medical practitioner, for
review. Using the interactive software, the surgeon can review the
plan, and manipulate the position of images of various implant
components relative to an image of the anatomy. The surgeon can
modify the plan and send it to the manufacturer with
recommendations or changes. The interactive review process can be
repeated until a final, approved plan, is sent to the
manufacturer.
[0029] After the surgical plan is approved by the surgeon,
patient-specific implants and associated tools, including, for
example, alignment guides, cutting/milling/reaming/broaching or
other tools for the surgical preparation of the joint or other
anatomy portion of the specific patient can be designed using a CAD
program or other three-dimensional modeling software, such as the
software provided by Materialise, for example, according to the
surgical plan. Computer instructions of tool paths for machining
the patient-specific tools and/or implants can be generated and
stored in a tool path data file. The tool path data can be provided
as input to a CNC mill or other automated machining system, and the
tools and implants can be machined from polymer, ceramic, metal or
other suitable material depending on the use, and sterilized. The
sterilized tools and implants can be shipped to the surgeon or
medical facility for use during the surgical procedure.
[0030] Patient-specific components or tools or portions discussed
below are generally constructed by a surgical plan approved by the
surgeon using thee-dimensional images of the specific patient's
anatomy and made to closely conform and mate substantially as a
negative mold of corresponding portions of the patient's anatomy,
including bone surfaces with or without associated soft tissue. MRI
scans, for example, allow modeling of soft tissue, such as
articular cartilage, and modeling of bone portions of different
densities, such as inner surfaces matching cortical and cancellous
bone, as discussed below.
[0031] The present teachings provide a bone-preserving design for a
hip prosthesis and associated tools. The procedure can conserve as
much of the natural femoral neck 82 of the patient as determined by
the surgeon depending on the specific patient by providing a
patient-specific femoral neck implant 100 for supporting a femoral
head implant 150, as illustrated in FIGS. 1, 1A and 2.
[0032] Referring to FIGS. 1 and 1A, an exemplary patient-specific
neck-preserving ("neck implant" for short) 100 can include a body
or stem 102 for introduction into the femoral neck 82 as described
below and an optional flange or collar 104 for abutment on a
resected surface 90 corresponding to a resection plane C of the
femoral neck 82 (shown in FIG. 4). A neck implant 100 without the
collar 104 is illustrated in FIG. 1A. The neck implant 100 can also
include a neck portion 106 which can be coupled to a corresponding
bore 152 of the femoral head implant 150 using a taper-to-taper
connection or other type of coupling. The stem 102 of the neck
implant 100 is designed to be patient-specific with a
three-dimensional outer surface 108 that is complementary and
closely nests and conforms to a cortical/cancellous interface
surface 88 where the cortical and cancellous bone layers meet
(referred to as cortical boundary surface 88 after the cancellous
bone is removed) of the femoral neck 82 of the patient only in one
position. Identifying the cortical/cancellous interface 88 enables
removing only the cancellous bone 84, thereby conserving the hard
cortical bone unmodified for engaging the complementary outer
surface 108 of the neck implant 100.
[0033] Specifically, the neck implant 100 is designed during the
pre-operative plan based on a three-dimensional computer model of
the femoral neck 82 of the patient as reconstructed from MRI, CT,
X-ray or other scans of the patient. Referring to FIG. 3, the
cortical/cancellous interface surface 88 between the cortical bone
86 and the cancellous bone 84 is illustrated after a planar neck
resection C is made to separate the natural femoral head from the
portion of the femoral neck 82 to be preserved below resected
surface 90. As can be seen from FIG. 2, the neck implant 100 can be
sized and shaped such that it does not extend beyond the femoral
neck 82 into the intramedullary canal of the femoral bone of the
patient. The neck implant 100 has a patient-specific depth into the
femoral neck 82 and a patient-specific angle relative to the femur.
Further, because the cortical/cancellous interface surface 88 has a
variable size and shape cross-section, the neck implant 100 has a
corresponding variable size and shape cross-section along a
longitudinal axis A of the neck implant 100, which is also specific
to each patient. For simplicity, the neck implant 100 is shown in
FIG. 1 with a variable oval/elongated and tapering cross-section
103, 103 (in two different locations), although it should be
understood that this geometry is merely exemplary and that the
shape and size cross-section 103 along the body of the neck implant
100 is patient-specific and mirrors the corresponding shape and
size of the cortical/cancellous interface surface 88 along the
femoral neck 82 of the specific patient. The cross-section 103 can
be oval or elongated and decreasing or tapering in size, but not
necessarily linearly. Further, the cross-section 103 may be and
generally is non-symmetric for a specific patient. The neck portion
106 of the neck implant 100 can also be designed to be aligned to a
patient-specific articulation direction along a second axis A'
which may be at an angle to the longitudinal axis A of the neck
implant A, as illustrated in FIG. 2. The neck portion 106 can be
also adjusted for an out-of-plane angle or neck version
adjustment.
[0034] Referring to FIGS. 3-5, to remove only the spongy cancellous
bone 84 while preserving substantially all the cortical bone 86, a
patient-specific cutting tool, broach or other bone-removing tool
200 can be designed during the preoperative plan based on the
three-dimensional computer model of the neck 82 of the patient.
Specifically, the broach 200 is designed to have a body 201 with an
outer peripheral three-dimensional cutting surface 202 extending
from a proximal end surface 204 to a distal end surface 210 of the
body 201 that closely nests and conforms or matches and is
complementary to the cortical/cancellous interface surface 88 only
in one position and such that only cancellous bone 84 is removed
and the cortical boundary surface 88 is exposed and maintained.
Similarly to the neck implant 100, the broach 200 is also a
patient-specific and has a variable in shape and size cross-section
203, which is generally oval/elongated and tapering, but not
necessarily linearly, along a longitudinal axis B of the broach.
Further, the cross-section 203 may be non-symmetric for a specific
patient. The cutting surface 202 is provided with cutting teeth and
channels or grooves for moving bone chips away from the cavity
created by the broach 200, as shown in FIG. 4.
[0035] Referring to FIGS. 5-7, the patient-specific broach 200 can
be coupled to a non-custom driver tool 300 by providing a coupling
interface between the proximal end surface 204 of the broach to a
distal surface 314 of the driver tool 300. The coupling interface
can include, for example, a broach coupling component 220, such as
a finger or rod or other protrusion 208 extending from the proximal
end surface 204 of the broach 200 to be received in a corresponding
bore or other opening 312 defined through the distal surface 314 of
the driver tool 300. The coupling interface can also include a
driver coupling component 320, such as an opening or bore 206
defined through the proximal end surface 204 for receiving a distal
portion 316 of a retractable bar or rod 310 of the driver tool 300.
The driver tool 300 can include a body 302, a handle bar 304, and a
proximal flange 318 for impaction. The retractable rod 310 extends
along the length of the body 302 and is biased by a proximal spring
308. The rod 310 can be deployed for engaging the broach 200 by
using a trigger 306 which can be operated by holding with one hand
the handle 304 and squeezing the trigger opening 305 with an index
finger. The broach 200 can be held securely with the driver tool
300, as shown in FIG. 7 and inserted into the femoral neck 82 to
remove the cancellous bone 84 and expose the cortical/cancellous
interface surface 88 for receiving the patient-specific neck
implant, as shown in FIGS. 1 and 2.
[0036] Referring to FIGS. 8 and 9 according to present teachings,
image data from CT, MRI, X-ray, ultrasound or other scanning of the
proximal femoral bone 80 and femoral neck 82 of a patient are
obtained at block 400. For modeling the cortical/cancellous
interface and identifying the cortical boundary surface 88, the
image data may be obtained from MRI scanning or other methods that
provide differentiation of bone and tissue layers based on density,
composition or other parameters. A three-dimensional computer image
model of the proximal femoral bone 80 and femoral neck 82 of the
patient can be constructed at block 402 using commercially
available software, as discussed above. The three-dimensional
cortical boundary surface 88 can be visible and identified and
confirmed in the image model at block 404 by the surgeon. A neck
resection plane can be selected and corresponding patient-specific
femoral alignment guides and/or femoral head resection guides can
be designed, as discussed, for example, in commonly assigned U.S.
application Ser. No. 12/893,306, filed Sep. 29, 2010 and U.S.
application Ser. No. 12/486,992, filed Jun. 18, 2009 of the
cross-reference section, and incorporated herein by reference. A
patient-specific broach 200 having a three-dimensional cutting
surface 202 matching and complementary to the cortical boundary
surface 88 in only one position can be designed at block 406 using
the computer image model of the patient's anatomy. A
patient-specific neck implant 100 having a three-dimensional
surface 108 matching and complementary to the cortical boundary
surface 88 in only one position can be designed and manufactured
using the computer image model of the patient's anatomy (block
408). The implant 100 can be impacted into the femoral neck 82 and
can also be porous coated for bone in-growth. As discussed above,
other patient-specific tools, including femoral alignment/cutting
guides to be used for resecting the femoral head, can also be
designed and manufactured using the image model of the patient's
anatomy according to the pre-operative plan.
[0037] The patient-specific neck implant 100, patient-specific
broach 200 and other custom or non-custom tools are sterilized and
shipped to the surgeon's site. Referring to FIG. 9,
intra-operatively, the natural femoral head can be resected from
the femoral neck 82 at a selected position and orientation (plane C
in FIG. 4) using, for example, patient-specific alignment guides,
patient-specific resection guides, non-custom guides and cutting
tools or combinations thereof (block 410). The resection plane C is
selected to preserve as much of the natural femoral neck 82 as
determined in the pre-operative plan. After the natural femoral
head is removed intra-operatively, the patient-specific broach 200
can be used to remove only the cancellous bone 84 from the femoral
neck 82 and expose the cortical boundary surface 88 of the femoral
neck 82, at block 412. The patient-specific neck implant 100 can
then be implanted, for example, by impaction, in only one position
(block 414), and mate with the exposed cortical boundary surface
88, as shown in FIG. 2. A femoral head implant 150 can be coupled
to the neck portion 106 of the neck implant 100. The femoral head
implant 150 can articulate with the natural acetabulum or an
acetabular implant 151, as determined and planned by the surgeon
for the specific patient.
[0038] Referring to FIGS. 10 and 10A, in some embodiments, a
patient-specific milling or cutting guide 600 can be used with a
milling tool 500 to remove the cancellous bone 84 and prepare the
femoral neck 82 for receiving a neck implant 100. The
patient-specific milling guide 600 can be designed during the
preoperative plan such that it can be mounted only in one position
on the femoral neck 82, after the femoral head is resected and
removed. The milling guide 600 can include a peripheral wall 602
and a first wall 608. The first wall 608 can be substantially flat
and have a first inner surface 609. The peripheral wall 602 extends
from the first wall 608 to a second surface 610 that is opposite
the first wall 608. The peripheral wall 602 includes a
three-dimensional patient-specific peripheral inner surface 604
that is configured to nestingly mate and conform only in one
position to a remaining (after resection) three-dimensional outer
peripheral surface 83 of the femoral neck 82. The first wall 608
includes a patient-specific bore 606 therethrough. The first inner
surface 609 is patient-specific and configured to mate and conform
to the resected surface 90, as shown in FIGS. 10 and 10A. The
patient-specific bore 606 is sized and shaped during the
preoperative plan to be patient-specific for guiding a cutting
portion 502 of a milling or other cutting tool 500 to remove the
cancellous bone 84 from the femoral neck 82 to the cortical
boundary 88 (interface between cortical and cancellous bone) for
receiving a neck implant, such as the patient-specific neck implant
100 discussed above. It is noted that the dimensions the
patient-specific milling guide 600, including the depth and size
the peripheral inner surface 604, is such that the patient-specific
milling guide 600 can be mounted over the resected femoral neck 82.
In some embodiments, the patient-specific milling guide can include
a split or hinge (not shown) along the insertion axis or can be
formed in two pieces couplable pieces in clamshell fashion, as
discussed in commonly assigned U.S. patent application Ser. No.
12/486,992, filed Jun. 18, 2009 and incorporated herein by
reference.
[0039] The patient-specific broach 200, the patient-specific
milling guide 600 and the patient-specific implant 100 can be
manufactured from biocompatible materials using machining, rapid
manufacturing by stereolithography, laser welding,
computer-assisted manufacturing using numerical machining or
robotic controllers. Patient-specific alignment and/or resection
guides for resecting and removing the femoral head can also be
designed from the image model and manufactured by the above methods
according to the pre-operative plan for the patient.
[0040] The foregoing discussion discloses and describes merely
exemplary arrangements of the present teachings. Furthermore, the
mixing and matching of features, elements and/or functions between
various embodiments is expressly contemplated herein, so that one
of ordinary skill in the art would appreciate from this disclosure
that features, elements and/or functions of one embodiment may be
incorporated into another embodiment as appropriate, unless
described otherwise above. Moreover, many modifications may be made
to adapt a particular situation or material to the present
teachings without departing from the essential scope thereof. One
skilled in the art will readily recognize from such discussion, and
from the accompanying drawings and claims, that various changes,
modifications and variations can be made therein without departing
from the spirit and scope of the present teachings as defined in
the following claims.
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