U.S. patent application number 14/483214 was filed with the patent office on 2014-12-25 for alignment guides with patient-specific anchoring elements.
The applicant listed for this patent is Biomet Manufacturing, LLC. Invention is credited to Thomas J. MAUCH, Robert METZGER, Kevin T. STONE.
Application Number | 20140378979 14/483214 |
Document ID | / |
Family ID | 44225128 |
Filed Date | 2014-12-25 |
United States Patent
Application |
20140378979 |
Kind Code |
A1 |
STONE; Kevin T. ; et
al. |
December 25, 2014 |
Alignment Guides With Patient-Specific Anchoring Elements
Abstract
A method for preparing a bone of a joint during joint
arthroplasty. The method includes mounting an alignment guide on
the bone of a patient along an alignment direction. The method
further includes anchoring the alignment guide into a cartilage of
the bone using a plurality of patient-specific anchoring elements
extending from an inner surface of alignment guide, each anchoring
element having a patient-specific length extending between the
inner surface and an end point of the corresponding anchoring
element.
Inventors: |
STONE; Kevin T.; (Winona
Lake, IN) ; MAUCH; Thomas J.; (South Bend, IN)
; METZGER; Robert; (Wakarusa, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Biomet Manufacturing, LLC |
Warsaw |
IN |
US |
|
|
Family ID: |
44225128 |
Appl. No.: |
14/483214 |
Filed: |
September 11, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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13041495 |
Mar 7, 2011 |
8864769 |
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14483214 |
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12973214 |
Dec 20, 2010 |
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13041495 |
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12955361 |
Nov 29, 2010 |
8591516 |
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12973214 |
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12938905 |
Nov 3, 2010 |
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12955361 |
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12938913 |
Nov 3, 2010 |
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12938905 |
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12893306 |
Sep 29, 2010 |
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12938905 |
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12893306 |
Sep 29, 2010 |
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12938913 |
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Sep 22, 2010 |
8377066 |
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12893306 |
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12714023 |
Feb 26, 2010 |
8241293 |
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12571969 |
Oct 1, 2009 |
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Jun 18, 2009 |
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Feb 20, 2009 |
8133234 |
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12211407 |
Sep 16, 2008 |
8608748 |
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12389901 |
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12039849 |
Feb 29, 2008 |
8282646 |
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May 31, 2007 |
8092465 |
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Jan 9, 2008 |
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Dec 20, 2010 |
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Current U.S.
Class: |
606/88 ; 606/87;
606/89 |
Current CPC
Class: |
A61B 17/152 20130101;
A61B 2034/108 20160201; A61B 17/151 20130101; A61B 34/10 20160201;
A61B 17/1764 20130101; A61B 2034/105 20160201 |
Class at
Publication: |
606/88 ; 606/87;
606/89 |
International
Class: |
A61B 17/17 20060101
A61B017/17 |
Claims
1. A method for preparing a bone of a joint during joint
arthroplasty comprising: mounting an alignment guide on the bone of
a patient along an alignment direction; and anchoring the alignment
guide into a cartilage of the bone using a plurality of
patient-specific anchoring elements extending from an inner surface
of alignment guide, each anchoring element having a
patient-specific length extending between the inner surface and an
end point of the corresponding anchoring element.
2. The method of claim 1, wherein the end points of the anchoring
elements define a geometric envelope that traces an outer surface
of the bone.
3. The method of claim 1, wherein the anchoring elements are
parallel to the alignment direction.
4. The method of claim 1, further comprising customizing the
plurality of patient-specific anchoring elements based on imaging
of a particular patient's anatomy.
5. The method of claim 1, wherein the inner surface is a
three-dimensional patient-specific surface including a customized
shape based on a multi-dimensional image of an outer cartilage
surface of the bone of the patient and configured to nestingly mate
to and be mounted on the outer cartilage surface of the bone of the
patient in only one position.
6. The method of claim 1, further comprising positioning the
aligning guide such that the anchoring elements penetrate through
an outer cartilage surface of the bone and penetrate through the
outer bone surface of the bone to anchor the alignment guide on the
bone of the patient.
7. The method of claim 6, wherein each anchoring element includes a
patient-specific cartilage-anchoring portion and a bone-anchoring
portion, the cartilage-anchoring portion having first and second
ends, the first end extending from the inner surface of the
alignment guide, the bone-anchoring portion extending from a
portion of the second end of the cartilage-anchoring portion.
8. The method of claim 1, further comprising mounting and anchoring
the alignment guide to a distal femoral bone.
9. The method of claim 1, further comprising mounting and anchoring
the alignment guide to a proximal tibial bone.
10. A method for preparing a bone of a joint during joint
arthroplasty comprising: mounting an alignment guide on an outer
cartilage surface of an articular cartilage of an underlying bone
of the patient; anchoring the alignment guide on the patient's
anatomy using a plurality of patient-specific anchoring elements
extending from a cartilage-engaging surface of alignment guide;
penetrating the cartilage with cartilage-engaging portions of the
anchoring elements, each cartilage-engaging portion having a length
extending between first and second ends; and penetrating an outer
bone surface of the underlying bone with bone-engaging portions of
the anchoring elements.
11. The method of claim 10, further comprising abutting and mating
the outer cartilage surface of the bone with shoulder surfaces of
the cartilage-engaging portions of the anchoring elements.
12. The method of claim 10, further comprising determining
patient-specific lengths of the cartilage-engaging portions of the
anchoring elements from the cartilage thickness at corresponding
locations of the bone of the patient.
13. The method of claim 12, further comprising determining the
cartilage thickness from a three-dimensional computer image of the
bone and articular cartilage reconstructed from medical scans of
the patient during a preoperative plan for the patient.
14. The method of claim 10, further comprising nestingly mating a
three-dimensional patient-specific cartilage engaging surface of
the alignment guide on the outer cartilage of the patient in only
one position.
15. The method of claim 10, wherein the inner surface is a
three-dimensional patient-specific surface including a customized
shape based on a multi-dimensional image of an outer cartilage
surface of the bone of the patient and configured to nestingly mate
to and be mounted on the outer cartilage surface of the bone of the
patient in only one position.
16. A method for preparing a bone of a joint during joint
arthroplasty comprising: mounting an alignment guide on the bone of
a patient along an alignment direction; and positioning the
aligning guide such that a plurality of patient-specific anchoring
elements extending from an inner surface of the alignment guide
penetrate through an outer cartilage surface of the bone and
penetrate through an outer bone surface of the bone for anchoring
the alignment guide on the bone of the patient, each
patient-specific anchoring element having a patient-specific length
extending between the inner surface and an end point of the
corresponding anchoring element.
17. The method of claim 16, wherein the inner surface is a
three-dimensional patient-specific surface including a customized
shape based on a multi-dimensional image of the outer cartilage
surface and configured to nestingly mate to and be mounted on the
outer cartilage surface in only one position.
18. The method of claim 16, further comprising abutting and mating
the outer cartilage surface of the bone with shoulder surfaces of
cartilage-engaging portions of the anchoring elements.
19. The method of claim 16, further comprising customizing the
plurality of patient-specific anchoring elements based on imaging
of the patient's own anatomy.
20. The method of claim 16, further comprising determining
patient-specific lengths of the cartilage-engaging portions of the
anchoring elements from cartilage thickness at corresponding
locations of the bone of the patient.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a divisional of U.S. application Ser.
No. 13/041,495, filed on Mar. 7, 2011, which claims the benefit of
U.S. Provisional Application No. 61/446,660, filed on Feb. 25, 2011
and is a continuation-in-part of U.S. application Ser. No.
12/973,214, filed Dec. 20, 2010, which is a continuation-in-part of
U.S. application Ser. No. 12/955,361 filed Nov. 29, 2010, which is
a continuation-in-part of U.S. application Ser. Nos. 12/938,905 and
12/938,913, both filed Nov. 3, 2010, each of which is a
continuation-in-part of U.S. application Ser. No. 12/893,306, filed
Sep. 29, 2010, which is a continuation-in-part of U.S. application
Ser. No. 12/888,005, filed Sep. 22, 2010, which is a
continuation-in-part of U.S. application Ser. No. 12/714,023, filed
Feb. 26, 2010, which is: a continuation-in-part of U.S. application
Ser. No. 12/571,969, filed Oct. 1, 2009, which is a
continuation-in-part of U.S. application Ser. No. 12/486,992, filed
Jun. 18, 2009, and is a continuation-in-part of U.S. application
Ser. No. 12/389,901, filed Feb. 20, 2009, which is a
continuation-in-part of U.S. application Ser. No. 12/211,407, filed
Sep. 16, 2008, which is a continuation-in-part of U.S. application
Ser. No. 12/039,849, filed Feb. 29, 2008, which: (1) claims the
benefit of U.S. Provisional Application No. 60/953,620, filed on
Aug. 2, 2007, U.S. Provisional Application No. 60/947,813, filed on
Jul. 3, 2007, U.S. Provisional Application No. 60/911,297, filed on
Apr. 12, 2007, and U.S. Provisional Application No. 60/892,349,
filed on Mar. 1, 2007; (2) is a continuation-in-part U.S.
application Ser. No. 11/756,057, filed on May 31, 2007, which
claims the benefit of U.S. Provisional Application No. 60/812,694,
filed on Jun. 9, 2006; (3) is a continuation-in-part of U.S.
application Ser. No. 11/971,390, filed on Jan. 9, 2008, which is a
continuation-in-part of U.S. application Ser. No. 11/363,548, filed
on Feb. 27, 2006; and (4) is a continuation-in-part of U.S.
application Ser. No. 12/025,414, filed on Feb. 4, 2008, which
claims the benefit of U.S. Provisional Application No. 60/953,637,
filed on Aug. 2, 2007.
[0002] This application is a divisional of U.S. application Ser.
No. 13/041,495, filed on Mar. 7, 2011, which is a
continuation-in-part of U.S. application Ser. No. 12/872,663, filed
on Aug. 31, 2010, which claims the benefit of U.S. Provisional
Application No. 61/310,752 filed on Mar. 5, 2010.
[0003] This application is a divisional of U.S. application Ser.
No. 13/041,495, filed on Mar. 7, 2011, which is a
continuation-in-part of U.S. application Ser. No. 12/483,807, filed
on Jun. 12, 2009, which is a continuation-in-part of U.S.
application Ser. No. 12/371,096, filed on Feb. 13, 2009, which is a
continuation-in-part of U.S. application Ser. No. 12/103,824, filed
on Apr. 16, 2008, which claims the benefit of U.S. Provisional
Application No. 60/912,178, filed on Apr. 17, 2007.
[0004] This application is a divisional of U.S. application Ser.
No. 13/041,495, filed Mar. 7, 2011, which is also a
continuation-in-part of U.S. application Ser. No. 12/103,834, filed
on Apr. 16, 2008, which claims the benefit of U.S. Provisional
Application No. 60/912,178, filed on Apr. 17, 2007.
[0005] This application is a divisional of U.S. application Ser.
No. 13/041,495, filed Mar. 7, 2011, which is also a
continuation-in-part of U.S. application Ser. No. 12/978,069, filed
Dec. 23, 2010, which is a continuation-in-part of U.S. application
Ser. No. 12/973,214, filed Dec. 20, 2010.
[0006] The disclosures of the above applications are incorporated
herein by reference.
INTRODUCTION
[0007] The present teachings provide various alignment guides with
patient-specific anchoring elements for joint arthroplasty.
SUMMARY
[0008] The present teachings provide for a method for preparing a
bone of a joint during joint arthroplasty. The method includes
mounting an alignment guide on a bone of a joint of a patient along
an alignment direction; and anchoring the alignment guide into a
cartilage of the bone using a plurality of patient-specific
anchoring elements extending from an inner surface of alignment
guide, each anchoring element having a patient-specific length
extending between the inner surface and an end point of the
corresponding anchoring element.
[0009] The present teachings further provide for a method for
preparing a bone of a joint during joint arthroplasty including:
mounting an alignment guide on an outer cartilage surface of an
articular cartilage of an underlying bone of the patient; anchoring
the alignment guide on the patient's anatomy using a plurality of
patient-specific anchoring elements extending from a
cartilage-engaging surface of alignment guide; penetrating the
cartilage with cartilage-engaging portions of the anchoring
elements, each cartilage-engaging portion having a length extending
between first and second ends; and penetrating an outer bone
surface of the underlying bone with bone-engaging portions of the
anchoring elements.
[0010] The present teachings still further provide for a method for
preparing a bone of a joint during joint arthroplasty. The method
includes mounting an alignment guide on a bone of a joint of a
patient along an alignment direction; and positioning the aligning
guide such that a plurality of patient-specific anchoring elements
extending from an inner surface of the alignment guide penetrate
through an outer cartilage surface of the bone and penetrate
through the outer bone surface of the bone for anchoring the
alignment guide on the bone of the patient, each anchoring element
having a patient-specific length extending between the inner
surface and an end point of the corresponding anchoring
element.
[0011] 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
[0012] The present teachings will become more fully understood from
the detailed description and the accompanying drawings,
wherein:
[0013] FIG. 1 is a plan view of a patient-specific alignment guide
with anchoring elements according to the present teachings;
[0014] FIG. 2 is an environmental sectional view of a
patient-specific alignment guide with anchoring elements according
to the present teachings;
[0015] FIG. 3 is an environmental perspective view of a
patient-specific femoral alignment guide with anchoring elements
according to the present teachings;
[0016] FIG. 4 is an environmental perspective view of a
patient-specific tibial guide with anchoring elements according to
the present teachings;
[0017] FIG. 5 is an environmental sectional view of a
patient-specific alignment guide with anchoring elements according
to the present teachings;
[0018] FIG. 5A is a detail of an anchoring element of FIG. 5;
[0019] FIG. 6 is an environmental perspective view of a
patient-specific femoral alignment guide with anchoring elements
according to the present teachings; and
[0020] FIG. 7 is an environmental perspective view of a
patient-specific tibial guide with anchoring elements according to
the present teachings.
DESCRIPTION OF VARIOUS ASPECTS AND EMBODIMENTS
[0021] The following description is merely exemplary in nature and
is in no way intended to limit the present teachings, applications,
or uses.
[0022] The present teachings generally provide various
patient-specific alignment and resection guides and other
associated instruments for use in orthopedic surgery, such as, for
example, in joint replacement or revision surgery. The
patient-specific guides can be used either with conventional or
patient-specific implant components and can be prepared with
computer-assisted image methods. Computer modeling for obtaining
three-dimensional (3-D) images of the patient's anatomy using MRI
or CT scans of the patient's anatomy, modeling of patient-specific
prosthesis components and the patient-specific guides and templates
can be configured and designed using various commercial CAD
programs and/or software, such as, for example, software by
Materialise USA, Ann Arbor, Mich.
[0023] Patient-specific alignment guides and implants are generally
configured to match the anatomy of a specific patient. The
patient-specific alignment guides are generally formed using
computer modeling based on the patient's 3-D anatomic image and
have an engagement surface that is made to conformingly contact and
match a three-dimensional image of the patient's bone surface (with
or without cartilage or other soft tissue) in only one position, by
the computer methods discussed above. The patient-specific
alignment guides are designed and prepared preoperatively using
anatomic landmarks, such as osteophytes, for example, and can be
mounted intra-operatively without any registration or other
guidance based on their unique patient-specific surface guided by
the patient's anatomic landmarks.
[0024] The patient-specific alignment guides can include
custom-made guiding formations, such as, for example, guiding bores
or cannulated guiding posts or cannulated guiding extensions or
receptacles that can be used for supporting or guiding other
non-custom instruments, such as drill guides, reamers, cutters,
cutting guides and cutting blocks or for inserting pins or other
fasteners according to a surgeon-approved pre-operative plan for
performing various resections as indicated for an arthroplasty,
joint replacement, resurfacing or other procedure for the specific
patient.
[0025] The patient-specific guides can also include resection or
cutting formations, such as cutting slots or cutting edges or
planes used for guiding a cutting blade to perform bone resections
directly through the patient-specific cutting guide. The
patient-specific guides can be used in minimally invasive surgery.
Various alignment/resection guides and preoperative planning
procedures are disclosed in commonly assigned and co-pending U.S.
patent application Ser. No. 11/756,057, filed on May 31, 2007; U.S.
patent application Ser. No. 12/211,407, filed Sep. 16, 2008; U.S.
patent application Ser. No. 11/971,390, filed on Jan. 9, 2008, U.S.
patent application Ser. No. 11/363,548, filed on Feb. 27, 2006; and
U.S. patent application Ser. No 12/025,414, filed Feb. 4, 2008. The
disclosures of the above applications are incorporated herein by
reference.
[0026] As disclosed, for example, in the above-referenced U.S.
patent application Ser. No. 11/756,057, filed on May 31, 2007, in
the preoperative planning stage for a joint replacement or revision
procedure, an MRI scan or a series of CT scans of the relevant
anatomy of the patient, such as, for example, the entire leg of the
joint to be reconstructed, can be performed at a medical facility
or doctor's office. The scan data obtained can be sent to a
manufacturer. The scan data can be used to construct a
three-dimensional image of the joint and provide an initial implant
fitting and alignment in a computer file form or other computer
representation. The initial implant fitting and alignment can be
obtained using an alignment method, such as alignment protocols
used by individual surgeons.
[0027] The outcome of the initial fitting is an initial surgical
plan that can be printed or provided in electronic form with
corresponding viewing software. The initial surgical plan can be
surgeon-specific, when using surgeon-specific alignment protocols.
The initial surgical plan, in a computer/digital file form
associated with interactive software, can be sent to the surgeon,
or other medical practitioner, for review. The surgeon can
incrementally manipulate the position of images of various implant
components in an interactive image of the joint. Additionally, the
surgeon can select or modify resection planes, types of implants
and orientations of implant insertion. After the surgeon modifies
and/or approves the surgical plan, the surgeon can send the final,
approved plan to the manufacturer.
[0028] After the surgical plan is approved by the surgeon,
patient-specific alignment/resection guides can be designed by
configuring and using a CAD program or other imaging 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 alignment guides can be generated
and stored in a tool path data file. The tool path can be provided
as input to a CNC mill or other automated machining system, and the
alignment guides can be machined from polymer, ceramic, metal or
other suitable material. The guides can also be manufactured by
various other methods, stereolithography, laser deposition,
printing, and rapid prototyping methods. The alignment guides are
sterilized and shipped to the surgeon or medical facility, for use
during the surgical procedure. Various patient-specific knee
alignment guides and associated methods are disclosed in the
commonly assigned U.S. application Ser. No. 11/756,057, filed on
May 31, 2007 (published as 2007/0288030 on Dec. 13, 2007), which is
incorporated herein by reference.
[0029] A patient-specific alignment guide can be used to drill
holes through corresponding bone of the joint surface and to guide
alignment pins through the holes. The alignment guide is then
removed leaving the alignment pins for supporting and cutting
instruments to make various resections in the bone in preparation
for receiving a joint implant.
[0030] The various patient-specific alignment guides can be made of
any biocompatible material, including, polymer, ceramic, metal or
combinations thereof. The patient-specific alignment guides can be
disposable and can be combined or used with other reusable non
patient-specific cutting and guiding components.
[0031] Referring to FIGS. 1 and 2, an exemplary alignment guide 100
is generally illustrated according to the present teachings. The
alignment guide 100 has a three-dimensional, curved inner surface
102. In some embodiments, the inner surface 102 nestingly matches
and is complementary to a corresponding surface of a patient
including various anatomic landmarks, such that the alignment guide
100 can be positioned and nested only in one position relative to
the anatomy of the specific patient along an alignment orientation
A. The patient's anatomy can be, for example, a bone 80 related to
a joint of the patient and including a layer of articular cartilage
83 over an outer bone surface 82. The articular cartilage 83 can
extend between the outer bone surface 82 and an outer cartilage
surface 84. In this embodiment, the inner surface 102 of the
patient-specific guide 100 is designed to match and mate with the
outer cartilage surface 84. The alignment guide 100 is designed to
be light-weight and can include various cut-outs or windows, such
as 104. The alignment guide 100 can include a plurality of
patient-specific anchoring elements 111 with end points 113. The
anchoring elements 111 can be, for example, spikes, or teeth or
pins extending from the anatomy-engaging surface 102 and sized and
configured to penetrate the cartilage up to the outer bone surface
82. The anchoring elements 111 can be engage the cartilage 83 at
several points for providing three-dimensional anchoring stability.
Multiple anchoring elements 111, such as, for example, five or
more, can be positioned uniformly or randomly relative to the inner
surface 102. Alternatively, a few anchoring elements 111, such as,
for example about three to five, can be included at selected or
pre-determined and relative positions.
[0032] In some embodiments, the anchoring elements 111 can be
configured to be parallel to an alignment/mounting direction A for
mounting and removing the guide 100, as shown in FIG. 2. Using
parallel anchoring elements 111 can avoid tearing the cartilage and
thereby reducing the anchoring stability of the alignment guide
100. The alignment/mounting direction can be determined during the
preoperative plan for the patient. In some embodiments, the
three-dimensional shape of the outer bone surface 82 (and,
optionally, the outer cartilage surface 84) can be represented in
three-dimensional computer models generated from the medical scans
of the patient and used to design the variable and patient-specific
height (or length) of each anchoring element 111 such that a
geometric envelope of the end points 113 traces a surface
complementary and mating with the outer bone surface 82.
Accordingly, only the outer bone surface 82 needs to be imaged
using standard bone imaging methods, such as CT and two-dimensional
X-rays, for example. Therefore, for these embodiments, is not
necessary to use methods, such as MRI, that can image the cartilage
or other soft tissue. In some embodiments, the length of the
anchoring elements is patient-specific. In some embodiments, the
length of the anchoring elements 111 can be greater that the
corresponding thickness of the cartilage 83, such that the inner
surface 102 of the alignment guide 100 does not contact the
cartilage.
[0033] In some embodiments, each anchoring element 111 can have a
length extending from the end point 113 to the inner surface 102
and approximating the thickness of the articular cartilage 83 of
the particular bone 80 of the patient at each specific location of
the anchoring element 111. The thickness of the cartilage 83 can
generally vary with the topography of the joint, i.e., the
cartilage distribution is non-uniform over a bone surface for a
single patient. There may also be additional gender-, age-, weight-
and disease-related cartilage variations. The cartilage of a
specific patient can also have various defects or other
idiosyncratic features. A detailed cartilage topography of a
specific patient can be determined during the pre-operative plan
from medical scans/images that can depict bone and soft tissue
surfaces, such as, for example, MRI images, CT images or other
imaging methods capable of showing bone and/or soft tissue.
[0034] In some embodiments, a uniform and constant height can be
selected for all the anchoring elements, equal, for example, to the
mean or the median or maximum or other value based on the thickness
variation of the cartilage of a particular joint surface of the
patient. When the maximum thickness of the cartilage is used as the
height of all the anchoring elements 111, the inner surface 102 of
the patient-specific guide 100 may not contact points of the outer
cartilage surface 84 where the cartilage 83 is thinner than the
maximum, i.e., there may be some areas of non-contact forming gaps
between the cartilage 83 and the anatomy-engaging surface 102.
Depending on the location of the cartilage 83, the thickness of the
cartilage 103 can vary from 0 to 6-7 mm, with higher thickness
generally corresponding to the knee patella of healthy young males.
In some embodiments, the inner surface 102 of the guide 100 does
not engage the cartilage 83 at all.
[0035] Referring to FIG. 3, an exemplary femoral alignment guide
200 according to the present teachings is configured for use with
the patient's distal femoral bone 80 (an example of the bone 80 of
FIG. 2). The femoral alignment guide 200 can have a light-weight
body 201 with a three-dimensional inner surface 202. In some
embodiments, the inner surface 202 may be a patient-specific
engagement surface that is complementary and made to closely
conform and mate with a portion of the anterior-distal articulating
or outer cartilage surface 84 of the patient's femur 80 based on
the pre-operative plan, as described above. The femoral alignment
guide 200 can include a window/opening 204 and first and second
distal guiding formations 206 defining guiding bores 207 for
guiding corresponding distal alignment pins 220. The femoral
alignment guide 200 can also include first and second anterior
guiding formations 208 defining guiding bores 209 for drilling
holes through the distal femur 80 and guiding corresponding
anterior alignment pins 222. Additionally, the femoral alignment
guide 200 can include a plurality of anchoring elements 211 that
are similar to the anchoring elements 111 described above in
reference to FIG. 2. The anchoring elements 211 are also designed
to penetrate the articular cartilage 83 for preventing small
rotational and/or translational displacements of the femoral
alignment guide 200 during use. The anchoring elements 211 can be
distributed randomly or uniformly to penetrate the entire outer
cartilage surface 84 which the patient-specific femoral guide 200
engages. Alternatively, a few discrete anchoring elements 211 can
be used instead, including at least three elements. The anchoring
elements 211 can be parallel defining an alignment/mounting
direction for inserting and removing the femoral alignment guide
200, as discussed above in connection with FIG. 2, and can engage
the cartilage at points arranged in a three-dimensional pattern for
providing anchoring stability. The length of the anchoring elements
211 can be variable and patient-specific such that a geometric
envelope of their end points traces a surface complementary and
mating with the outer bone surface 82.
[0036] Referring to FIG. 4, a representative tibial
alignment/resection guide 300 is illustrated according to the
present teachings. The tibial alignment guide 300 can include a
body 301 having a proximal portion 303, an anterior portion 305 and
a three-dimensional inner surface 302. In some embodiments, the
inner surface can be a patient-specific surface that is
complementary and made to closely conform and mate with a portion
of an anterior surface 76 and a portion of a proximal surface or
outer cartilage surface 74 of the patient's tibia 70 in only one
position based on the pre-operative plan. The tibial alignment
guide 300 can include first and second proximal guiding formations
306 defining guiding bores 307 for corresponding proximal alignment
pins or other fasteners 323. The tibial alignment/resection guide
300 can also include first and second anterior guiding formations
308 defining guiding bores 309 for corresponding anterior alignment
pins or other fasteners 327. As discussed above in connection with
alignment guides in general and the femoral alignment guide 200 in
particular, the tibial alignment guide 300 can be used to drill
reference holes for the corresponding proximal and anterior
alignment pins 323, 327, which can then be re-inserted as needed
for each resection and corresponding resection block after the
tibial alignment/resection guide 300 is removed. The tibial
alignment/resection guide 300 can optionally include a resection
guiding slot 310 for guiding a tibial resection according to the
pre-operative plan for the patient. Additionally, the tibial
alignment guide 300 can include a plurality of anchoring elements
311 that are similar to the anchoring elements 111 described above
in reference to FIG. 2. The anchoring elements 311 are designed to
penetrate the tibial cartilage 73 for preventing small rotational
and/or translational displacements of the tibial alignment guide
300 during use. The anchoring elements 311 can be distributed
randomly or uniformly to penetrate the tibial cartilage 73 between
the bone surface 72 and the outer cartilage surface 74 of the
proximal tibia over the area that the proximal portion 303 of the
patient-specific tibial alignment guide 300 engages. Alternatively,
a few discrete anchoring elements 311 can be used instead,
including at least three elements in a three-dimensional
arrangement. Generally, the anchoring elements 311 can be parallel
to an alignment/mounting direction (see FIG. 2) and engage the
cartilage at points arranged in a three-dimensional pattern for
stability. The length of the anchoring elements 311 can be variable
and patient-specific such that a geometric envelope of their end
points traces a surface complementary and mating with the outer
bone surface 72, as discussed above.
[0037] Referring to FIGS. 5 and 5A, a detail of an alignment guide
400 with patient-specific anchoring elements 450 is illustrated
according to the present teachings. FIG. 6 illustrates a femoral
alignment guide 500 similar to the femoral alignment guide 200, but
with patient-specific anchoring elements 550 similar to the
patient-specific anchoring elements 450 of FIG. 5. Similar elements
between alignment guides 200 and 500 are referenced with numerals
having the same second and third digits. FIG. 7 illustrates a
tibial alignment guide 600 similar to the tibial alignment guide
300, but with patient-specific anchoring elements 650 similar to
the patient-specific anchoring elements 450 of FIG. 5. Similar
elements between alignment guides 300 and 600 are referenced with
numerals having the same second and third digits. The
patient-specific anchoring elements 450, 550 and 650 are similar
and are described in reference to FIG. 5, which illustrates
generically a portion of a patient-specific alignment guide 400. At
least three anchoring elements 450 in a three dimensional pattern
can be used for providing anchoring stability in three dimensions.
In some embodiments, the alignment guides 400, 500 and 600 can also
be patient-specific with three-dimensional cartilage engaging
surfaces that can nestingly mate to and be mounted on the outer
surface of the articular cartilage of the patient in only one
position.
[0038] The patient-specific anchoring elements 450 can be designed
using a three-dimensional computer image of the patient's anatomy
including the articular cartilage surface and the underlying bone
during a preoperative plan for the patient. The three-dimensional
image can be constructed based on medical scans of he patient, such
as MRI, CT, ultrasound or other scans equipped or modified to image
soft tissue, such as articular cartilage and using commercially
available CAD/CAD imaging software.
[0039] Referring to FIGS. 5 and 5A, the patient-specific anchoring
elements 450 are configured for penetrating the articular cartilage
83 and anchoring into the underlying bone 80 through the outer bone
surface 82. Each anchoring element 450 can include a
cartilage-anchoring portion 452 and a bone-anchoring portion 454.
The cartilage-anchoring portion 452 can be in the form of an
elongated element having a first end 458 attached to an
anatomy-engaging surface 402 of the alignment guide 400 and an
opposite second end 456 in the form of a patient-specific surface
460 designed for abutting and closely mating with the outer bone
surface 82. The geometric envelope of the patient-specific surfaces
460 of all the anchoring elements 450 can be designed during the
pre-operative plan to be patient-specific relative to the outer
bone surface 82, such that the surface 460 to be complementary and
closely mate and conform to the outer bone surface 82. Accordingly,
the length of each cartilage-anchoring portion 452 from the first
end 458 to the second end 456 is patient-specific and can be
selected to be equal to the thickness of the patient's cartilage 83
at the corresponding location for each anchoring element 450. The
bone-anchoring portion 454 can be in the form of a spike or pin
extending from the second end 456 of the cartilage-anchoring
portion 452 for penetrating the outer bone surface 82 and lodging
into the bone 80.
[0040] With continued reference to FIGS. 5 and 5A, the
patient-specific surface 460 forms a shoulder or step 463 between
the second end 456 of the cartilage-anchoring portion 452 and the
bone-anchoring portion 454. The cartilage-anchoring portion 452
penetrates the cartilage 83 and can be seated in a pocket formed in
the cartilage 83 when the alignment guide 400 is pressed against
the bone 80 until the bone-anchoring portion 454 penetrates the
bone 80 and the patient-specific surface 460 nestingly mates and
seats on the outer bone surface 82 under the cartilage. The bone
anchoring portion 454 can be made of a material of sufficient
strength and/.or rigidity to penetrate the bone 80. In some
embodiments, the bone anchoring portion 454 and the
cartilage-anchoring portion 452 can be made of different materials.
In some embodiments, the bone-anchoring portion 454 can be made
separately from the cartilage-anchoring portion 452 and have a
portion 459 inserted permanently or removably into the
cartilage-anchoring portion 452. In other embodiments, the bone
anchoring portion 454 and the cartilage-anchoring portion 452 can
be made as one integral or monolithic piece. In some embodiments,
the anchoring elements can be parallel to an alignment orientation
A. In some embodiments, the anchoring elements can be perpendicular
to bone surface 82.
[0041] With continued reference to FIGS. 5 and 5A, the
cartilage-engaging surface 402 can be designed during the
pre-operative plan of the patient as a three-dimensional
patient-specific surface that complementarily and nestingly mates
with the outer cartilage surface 84 in only one position. In some
embodiments, conformance to small variations, such as minute
defects, in the outer cartilage surface 84 may be relaxed, although
the alignment guide 400 can still be mounted on the outer cartilage
surface in only one position and is still patient-specific. In this
respect, a small gap "g" may be formed between the outer cartilage
surface 84 and the anatomy-engaging surface 402 of the alignment
guide 400 in certain locations depending on the profile and
condition of the cartilage 83. The cartilage-anchoring portion 452
of each anchoring element 450 has a patient specific length and a
patient-specific bone-abutting surface 460. The cartilage-anchoring
portion 452 can generally have a diameter or major cross-sectional
dimension of about 2-5 mm, while the major cross-sectional
dimension of the bone-anchoring portion 454 can be about 1-2 mm.
The gap g can also be of the order of 1-2 mm.
[0042] As discussed above, the patient-specific anchoring elements
111, 211, 311, 450, 550, 650 can be integrated with various
patient-specific guides designed to engage a cartilage bearing
articulating surface of a joint, such as the distal femur and the
proximal tibia for a knee joint. The patient-specific anchoring
elements can also be used, for example, with guides designed to
engage the articular surfaces of the hip joint or shoulder
joint.
[0043] 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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