U.S. patent application number 13/042382 was filed with the patent office on 2011-09-01 for tibial resurfacing system and method.
This patent application is currently assigned to Arthrosurface, Inc.. Invention is credited to Steven W. Ek, George Sikora.
Application Number | 20110213375 13/042382 |
Document ID | / |
Family ID | 44542620 |
Filed Date | 2011-09-01 |
United States Patent
Application |
20110213375 |
Kind Code |
A1 |
Sikora; George ; et
al. |
September 1, 2011 |
Tibial Resurfacing System and Method
Abstract
An implant resection system for preparing an implant site to
replace a defect in an articular surface of a first bone includes a
guide configured to be coupled generally perpendicular to the first
bone proximate to the defect. The guide includes a body portion
defining a plurality of excision passageways. The excision
passageways each define a generally cylindrical core pathway
configured to extend generally perpendicular to the first bone
which partially overlaps with an adjacent generally cylindrical
core pathway. A projection associated with each of the plurality of
the generally cylindrical core pathways defines a truncated
cylindrical excision site extending through a portion of the
articular surface. Each truncated cylindrical excision site
partially overlaps with at least one adjacent truncated cylindrical
excision site.
Inventors: |
Sikora; George;
(Bridgewater, MA) ; Ek; Steven W.; (Bolton,
MA) |
Assignee: |
Arthrosurface, Inc.
Franklin
MA
|
Family ID: |
44542620 |
Appl. No.: |
13/042382 |
Filed: |
March 7, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11779044 |
Jul 17, 2007 |
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13042382 |
|
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61310774 |
Mar 5, 2010 |
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60807538 |
Jul 17, 2006 |
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Current U.S.
Class: |
606/87 |
Current CPC
Class: |
A61F 2/389 20130101;
A61B 17/1764 20130101; A61B 17/1637 20130101; A61B 17/1675
20130101; A61B 17/157 20130101; A61B 2090/062 20160201 |
Class at
Publication: |
606/87 |
International
Class: |
A61B 17/56 20060101
A61B017/56 |
Claims
1. An implant resection system for preparing an implant site to
replace a defect in an articular surface of a first bone, said
implant resection system comprising: a guide configured to be
coupled generally perpendicular to said first bone proximate to
said defect, said guide comprising a body portion defining a
plurality of excision passageways, said excision passageways each
defining a generally cylindrical core pathway configured to extend
generally perpendicular to said first bone which partially overlaps
with an adjacent generally cylindrical core pathway, wherein a
projection associated with each of said plurality of said generally
cylindrical core pathways defines a truncated cylindrical excision
site extending through a portion of said articular surface, and
wherein each truncated cylindrical excision site partially overlaps
with at least one adjacent truncated cylindrical excision site.
2. The implant resection system of claim 1, further comprising: an
arm extending outwardly from a distal face of said body portion of
said guide; and a spoon disposed about a distal end of said arm,
said spoon configured to be disposed between said articular surface
of said first bone and an articular surface of a cooperating
bone.
3. The implant resection system of claim 2, wherein said spoon
further comprises a generally convex base portion configured to
abut against said articular surface of said first bone.
4. The implant resection system of claim 3, wherein said spoon
further comprises a generally concaved upper portion configured to
abut against said articular surface of said cooperating bone.
5. The implant resection system of claim 2, further comprising: a
locking passageway extending through a portion of said arm; and at
least one pin configured to be advanced through said locking
passageway and into said first bone and to secure said spoon
relative to said first bone.
6. The implant resection system of claim 5, wherein said locking
passageway is configured to align said at least one pin such that
said at least one pin extends into said first bone proximate to the
meniscus.
7. The implant resection system of claim 1, further comprising: a
locking passageway extending through a portion of said body
portion; and at least one pin configured to be advanced through
said locking passageway and into said first bone and to secure said
body portion relative to said first bone.
8. The implant resection system of claim 1, further comprising: a
dowel having a longitudinal passageway, said dowel configured to be
advanced through a first of said plurality of excision passageways
and to abut against said first bone; and a pin configured to be
advanced through said longitudinal passageway of said dowel and
into said first bone; wherein said dowel and said pin are
configured to secure said body portion relative to said first
bone.
9. The implant resection system of claim 8, further comprising a
locking feature to secure said dowel within said first excision
passageway.
10. The implant resection system of claim 1, further comprising a
core drill configured to advanced through a first one of said
plurality of excision passageways along a first of said generally
cylindrical core pathways to remove a portion of said bone and said
articular surface to define a first of said plurality of partially
overlapping truncated cylindrical excision sites.
11. The implant resection system of claim 10, further comprising: a
pin configured to be advanced through said first excision
passageway and into said first bone; wherein said core drill
further comprises a centering bushing disposed within a core cavity
of said core drill, said centering bushing configured to be
advanced over said pin and to center said core drill along said
generally cylindrical core pathway associated with said first
excision passageway.
12. The implant resection system of claim 1, wherein said plurality
of excision passageways includes a first, a second, and a third
excision passageway, said third excision passageway partially
overlapping said first and said second excision passageways;
wherein said guide further comprises a first and a second
protrusion configured to extend from said body portion and to be
received in a truncated cylindrical excision site associated with
said first and said second excision passageway, respectively.
13. The implant resection system of claim 12, wherein said first
and said second protrusions further comprise alignment passageways,
each alignment passageway configured to be advanced over an
associated pin to secure said guide to said first bone while a core
drill is advanced through said third excision passageway to form an
excision site associated with said third excision passageway.
14. The implant resection system of claim 1, further comprising an
implant comprising: a load bearing surface having a contour
substantially corresponding to a contour of the articular surface
corresponding to said implant site; and a bone facing surface
having a contour substantially corresponding to the contour of said
plurality of truncated cylindrical excision sites formed in said
first bone.
15. The implant resection system of claim 14, wherein said bone
facing surface further comprises a plurality of relief cavities
configured secure said implant to said bone.
16. The implant resection system of claim 14, further comprising a
keel extend generally away from said bone facing surface, said keel
configured to engage a corresponding notch formed in one of said
plurality of truncated cylindrical excision sites.
17. The implant resection system of claim 14, wherein said first
bone is a tibia, and wherein said implant includes a "D" shaped
cross-section.
18. The implant resection system of claim 14, wherein said implant
comprises an upper portion configured to be secured to a lower
portion, said upper portion comprising said load bearing surface
and said lower portion comprising said bone facing surface.
19. A method for preparing an implant site to replace a defect in
an articular surface, said method comprising: securing a guide to
bone proximate said defect, said guide comprising a body portion
defining a plurality of excision passageways, each excision
passageway defining a generally cylindrical core pathway which
partially overlap with an adjacent generally cylindrical core
pathway; and advancing at least one drill through said plurality of
excision passageways along said generally cylindrical core pathways
to form a plurality of partially overlapping truncated cylindrical
excision sites extending through said articular surface.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional
Patent Application No. 61/310,774, filed Mar. 5, 2010, which is
fully incorporated herein by reference. This application is also a
continuation-in-part of U.S. patent application Ser. No.
11/779,044, filed Jul. 17, 2007, entitled SYSTEM AND METHOD FOR
TISSUE RESECTION, which claims the benefit of U.S. Provisional
Patent Application Serial No. 60/807,538, filed Jul. 17, 2006, the
entire disclosures of all of which are incorporated fully herein by
reference.
FIELD
[0002] This disclosure relates to devices and methods for the
repair of defects that occur in articular cartilage on the surface
of bones, particularly the knee.
BACKGROUND
[0003] Articular cartilage, found at the ends of articulating bone
in the body, is typically composed of hyaline cartilage, which has
many unique properties that allow it to function effectively as a
smooth and lubricious load-bearing surface. When injured, however,
hyaline cartilage cells are not typically replaced by new hyaline
cartilage cells. Healing is dependent upon the occurrence of
bleeding from the underlying bone and formation of scar or
reparative cartilage called fibrocartilage. While similar,
fibrocartilage does not possess the same unique aspects of native
hyaline cartilage and tends to be far less durable.
[0004] In some cases, it may be necessary or desirable to repair
the damaged articular cartilage using an implant. While implants
may be successfully used, the implant should have a shape
substantially corresponding to the articular cartilage proximate
the area where the implant is to be placed in order to maximize the
patient's comfort, minimize damage to surrounding areas, and
maximize the functional life of the implant.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] Features and advantages of the present invention are set
forth by description of embodiments consistent with the present
invention, which description should be considered in conjunction
with the accompanying drawings wherein:
[0006] FIG. 1 is a schematic diagram illustrating an incision
proximate the knee;
[0007] FIG. 2 is a perspective view illustrating one embodiment of
a drill guide coupled to the tibia consistent with the present
disclosure;
[0008] FIG. 3 is a perspective view illustrating dowels advanced
within the drill guide consistent with the present disclosure;
[0009] FIG. 4 is a perspective view illustrating pin advanced
within the dowels in the drill guide consistent with the present
disclosure;
[0010] FIG. 5 is a bottom plan view of one embodiment of a drill
guide as generally shown in FIG. 4 consistent with the present
disclosure;
[0011] FIG. 6 is a perspective view illustrating a drill bit
advanced into the drill guide consistent with the present
disclosure;
[0012] FIG. 7 is a perspective view of one embodiment of a drill
bit consistent with the present disclosure;
[0013] FIG. 8 illustrates one embodiment of a first and second
excision site formed on the tibial articular surface and a second
drill guide coupled thereto consistent with the present
disclosure;
[0014] FIG. 9 is a perspective view of one embodiment of a third
excision site formed on the tibial articular surface using the
second drill guide consistent with the present disclosure;
[0015] FIG. 10 is a perspective view of another embodiment of a
first, second, and third excision site formed on the tibial
articular surface using the first and/or second drill guides
consistent with the present disclosure;
[0016] FIG. 11 is a perspective bottom view of one embodiment of an
implant consistent with the present disclosure;
[0017] FIG. 12 is a cross-sectional side view of another embodiment
of an implant consistent with the present disclosure; and
[0018] FIG. 13 is a cross-sectional view of yet another embodiment
of an implant consistent with the present disclosure.
DETAILED DESCRIPTION
[0019] By way of summary, one embodiment of the present disclosure
may feature a system and method for repairing a portion of the
articular surface proximate to a defect. While the present
disclosure will be described in terms of a system and method for
repairing a portion of the tibial articular surface, it should be
understood that the system and method may be used to repair other
articular surfaces (such as, but not limited to, femoral articular
surfaces and the like). The system and method may include securing
a one or more guides/jigs defining one or more passageways to a
portion of the tibia (e.g., immediately below the tibial articular
surface) proximate to the defect. The passageways may define a
generally cylindrical core pathway for a drill bit (i.e., a coring
drill bit). When the guide is secured to the femur, the generally
cylindrical core pathway may partially intersect/overlap with the
articular surface and a portion of the bone beneath the articular
surface. A first truncated cylindrical excision site may be formed
in the articular surface and/or bone beneath the articular surface
by advancing the drill along the core pathway. The drill may have a
diameter large enough to remove a portion of the articular surface
as it is advanced through the guide and into the articular surface.
Additional truncated cylindrical excision sites may also be formed.
One or more of the additional truncated cylindrical excision sites
may partially overlap with adjacent truncated cylindrical excision
sites.
[0020] The guide and/or the drill may include a depth feature
configured to control the depth of the truncated cylindrical
excision site formed in the articular surface/bone. The depth
feature may prevent the drill from being advanced too far, thereby
preventing the drill from accidentally damaging any structures
proximate to the excision sites (e.g., nerves). The system and
method may also include an implant having a load bearing surface
having a surface contour/geometry based on the surface
contour/geometry of the patient's original removed articular
surface. For example, the surface contour/geometry of the load
bearing surface may be based on one or more measurements taken of
the patient's original articular surface. The implant may also
feature a bone facing or distal surface having a surface
contour/geometry configured to be received in the truncated
cylindrical excision sites.
[0021] Turning now to FIG. 1, a tibia 10 is generally illustrated.
As may be appreciated, the tibial articular surface 12 may include
a tibial plateau comprising a plurality of concaved surfaces 14a,
14b configured to articulate with the femoral condyles (not shown
for clarity). It may be further appreciated that the tibial
articular surface 12 may include additional concaved surfaces not
shown for the sake of clarity. One or more of the concaved surfaces
(e.g., concaved surface 14a) may include a defect 13 in the tibial
articular surface 12 to be repaired. On the distal side of the
tibia 10, a nerve bundle 16 is located. As described herein, the
system and method according to one embodiment of the present
disclosure may be configured to avoid damaging the nerve bundle
when forming the excision site(s).
[0022] For illustrative purposes, the following will describe a
system and method for preparing an implant site comprising three
partially overlapping truncated cylindrical excision sites and an
implant configured to fit therein. As may be appreciated, the
system and method according to the present disclosure may be used
to form an implant site having greater than or fewer than three
partially overlapping truncated cylindrical excision sites. As will
be evident from the following description, the truncated
cylindrical excision sites may be formed by drilling along the
anterior-posterior plane (i.e., from an anterior face of the tibia
10 and extending generally towards the posterior face of the tibia
10).
[0023] Turning now to FIG. 2, one embodiment of a first guide 20
secured to the tibia 10 is generally illustrated consistent with
the present disclosure. The first guide 20 may include a jig 22 and
a spoon 24. The jig 22 may include a body portion 26 defining two
excision passageways 28a, 28b. As explained herein, the excision
passageways 28a, 28b may each define a generally cylindrical core
pathway for a drill bit which may be used to form a first and a
second truncated cylindrical excision site on the tibial articular
surface 12. As shown, the first and the second excision passageways
28a, 28b may be offset relative to each other (i.e., the first and
the second excision passageways 28a, 28b may be separated by a
distance generally perpendicular to the longitudinal axes of the
first and the second excision passageways 28a, 28b such that the
first and the second truncated cylindrical excision sites formed in
the articular surface 12 do not overlap as described herein).
[0024] The position of the jig 22 (and in particular, the excision
passageways 28a, 28b) may be set based on, at least in part, the
spoon 24. In particular, the spoon 24 may include a generally
convex base portion 30 having a surface contour substantially
corresponding to the curvature of the concaved surface 14a being
repaired (e.g., the concaved surface 14a which has the defect 13).
The upper portion 32 of the spoon 24 may have a generally concaved
surface (e.g., generally corresponding to the curvature of the
concaved surface 14a being repaired). The spoon 24 may have a
cross-sectional thickness configured to facilitate advancement of
the spoon 24 between the tibial articular surface 12 and the
femoral condyles (not shown). For example, the cross-sectional
thickness of the spoon 24 may be selected to provide sufficient
rigidity to align the jig 22 relative to the tibial articular
surface 12 (and in particular, the defect 13 on the concaved
surface 14a) while also minimizing the required separation between
the tibia 10 and the femur.
[0025] The spoon 24 may be an integral component of the jig 22
(e.g., a unitary or single one-piece structure) or may be
configured to be releasably coupled to the jig 22. For example, the
spoon 24 may include an arm portion 36 configured to extend
generally outwardly from a distal face 38 (e.g., a bone facing
surface) of the jig 22. The size and shape of the arm portion 36
may be configured to allow a portion of the distal face 38 to be
disposed proximate to the perimeter (e.g., proximate to the
meniscus 40) when the spoon 24 is disposed on the concaved surface
14a such that the generally cylindrical core pathways associated
with the first and second excision passageways 28a, 28b partially
overlap with the tibial articular surface 12.
[0026] In practice, the first guide 20 may be positioned relative
to the defect 13 on the concaved surface 14a by advancing the spoon
24 between the tibial articular surface 12 and the femur such that
the base portion 30 of the spoon 24 is disposed over at least a
portion of the defect 13 on the tibial articular surface 12. The
spoon 24 may be advanced until the distal face 38 of the jig 22
generally abuts against a portion of the tibia 10 (e.g., proximate
to the meniscus 40). The size and shape of the base portion 30 as
well as the arm portion 36/distal face 38 may be configured to
generally center the spoon 24 within the concaved surface 14a.
[0027] Once the spoon 24 is positioned over the defect 13, the
spoon 24 and the jig 22 may be secured to the tibia 10 using one or
more pins 32 or the like extending through one or more locking
passageways 34 in the spoon 24 and/or the jig 22. For example, the
spoon 24 may include a spoon locking passageway 34a extending
through a portion of the spoon 24 (e.g., the arm portion 36)
configured to align a pin 32a into the tibial bone beneath the
tibial articular surface 12. Alternatively (or in addition), the
jig 22 may include a jig locking passageway 34b extending through a
portion of the body 26 configured to align a pin 32b into the
tibial bone beneath the tibial articular surface 12. While two pins
32a, 32b are shown, it should be appreciated that the first guide
20 may be secured using greater than or fewer than two pins 32a,
32b.
[0028] The pins 32a, 32b may include depth feature 33a, 33b
configured to control the depth of the pins 32a, 32b in the bone 10
(i.e., to prevent the pins 32a, 32b from being set too deep or too
shallow into the bone 10). The depth feature 33a, 33b may comprise
an indicia (e.g., but not limited to, a laser marking, groove, or
the like) which may be aligned with the proximal end of the
passageways 34a, 34b. Pin 32a may extend a smaller distance into
the tibia 10 compared to pin 32b.
[0029] Turning now to FIG. 3, the first guide 20 may optionally be
secured to the tibia 10 by advancing one or more dowels or bushings
40a, 40b against the bone 10. For example, a first and a second
dowel 40a, 40b may be advanced through the first and second
excision passageways 28a, 28b, respectively. One or more of the
dowels 40a, 40b may feature a tapered tip 42a, 42b and a
longitudinally disposed passageway 44a, 44b (a proximal end of the
dowels 40a, 40b is shown in cross-section to better illustrate the
passageway 44a, 44b). The dowels 40a, 40b may be advanced through
the passageways 28a, 28b until the tapered tip 42a, 42b engages
against (e.g., abuts) a portion of the tibia 10 (e.g., proximate to
the meniscus 40). Once the dowels 40a, 40b abut the tibia 10, the
dowels 40a, 40b may be locked into position relative to the jig 22
using locking fasteners 46a, 46b. The locking fasteners 46a, 46b
may include, but are not limited to, a set screw, biased tab,
ratchet mechanism, or the like.
[0030] Alignment pins 48a, 48b may be advanced through the
passageways 44a, 44b in the dowels 40a, 40b and into the tibia 10
as generally illustrated in FIG. 4. Similar to the pins 34a, 34b,
the alignment pins 48a, 48b may include a depth feature 50a, 50b
configured to control the depth of the alignment pins 48a, 48b into
the bone 10 (i.e., to prevent the alignment pins 48a, 48b from
being set too deep or too shallow within the bone 10). The depth
feature 50a, 50b may comprise an indicia (e.g., but not limited to,
a laser marking, groove, or the like) which may be aligned with the
proximal end of the passageway 44a, 44b in the dowels 40a, 40b.
[0031] FIG. 5 is a bottom plan view of the first guide 20 generally
illustrating one embodiment of the position of the alignment pins
48a, 48b as well as pin 32b relative to the spoon 24. As can be
seen, depth features 50a, 50b, 33b are generally aligned with the
respective passageways 44a, 44b, 34b such that the distal ends of
the pins 48a, 48b, 32b are generally aligned with the distal
perimeter of the spoon 24. As such, the distal ends of the pins
48a, 48b, 32b do not extend beyond the tibial bone 10. It should be
appreciates, however, that the position of the distal ends of the
pins 48a, 48b, 32b may be disposed shallower (i.e., closer towards
the first guide 20).
[0032] Once the first guide 20 is secured to the tibia 10, a first
and a second truncated cylindrical excision site may be formed in
the tibial articular surface 12 and/or bone 10. The first and
second truncated cylindrical excision sites may correspond to a
projection of the cylindrical core pathways defined by the excision
passageways 28a, 28b intersecting with the tibial articular surface
12 and/or bone 10. For example, a dowel 40a may be removed from the
excision passageway 28a, leaving the pin 48a remaining as generally
illustrated in FIG. 6. A cannulated drill 60 may then be advanced
over the pin 48a and through the excision passageway 28a to form a
first truncated cylindrical excision site. While dowel 40a is shown
removed, the order in which the dowels 40a, 40b are removed may be
altered.
[0033] One embodiment of a cannulated drill 60 is generally
illustrated in FIG. 7. The cannulated drill 60 may feature a core
drill bit 62 and optionally a shank portion 64. The shank portion
64 may include a multi-faceted proximal end configured to be
secured to a drill (e.g., a hand drill, electric drill, pneumatic
drill or the like). Alternatively, a proximal end of the core drill
bit 62 may be directly coupled to the drill.
[0034] The core drill bit 62 may include a cutting surface 66 (for
example, comprising a plurality of cutting teeth 67) disposed about
a distal end of the barrel 63. The cutting surface 66 may be evenly
disposed around the generally circular distal end of the barrel 63.
The barrel 63 may include an outer diameter substantially
corresponding to the inner diameter of the excision passageway 28a.
For example, the core drill 62 may have an outer diameter selected
from the range of 8-12 mm, for example, 10-11 mm. The barrel 63 may
define a core cavity 68 configured to receive the removed portion
of the tibial articular surface 12 and bone 10. As may be
appreciated, the only portion of the tibial articular surface 12
and bone 10 that is cut by the core drill bit 60 corresponds to the
thickness of the cutting surface 66, which itself is a function of
the wall thickness of the barrel 63. As such, these thicknesses may
be selected to remove the least amount of material while also
providing the necessary rigidity and/or strength to the core drill
bit 60.
[0035] The core drill bit 62 may optionally feature one or more
windows 70 disposed along the length of the barrel 63. The window
70 may allow air, fluid, and cutting chips to exit the barrel 63.
In addition, the window 70 may also allow the user to align the
core drill bit 62 with the first guide 20 and/or pins to control
the depth of the excision site (i.e., the length of the excision
site as measured across the tibial articular surface 12). For
example, a proximal end of the window 70 may be generally aligned
with the opening on the excision passageway 28a to control the
depth of the resulting excision site.
[0036] The core drill bit 62 may also optionally include a
centering bearing 72 configured facilitate alignment of the core
drill bit 62 as the core drill bit 62 is advanced into the tibial
articular surface 12 and bone 10. The centering bearing 72 may be
translatably disposed along the longitudinal axis of the core drill
bit 62 and may include a passageway 74 configured to receive the
pin 48a. For example, the centering bearing 72 may be initially
located near the distal end of the barrel 62. As the core drill bit
62 is advanced within the excision passageway 28a, the pin 48a may
be received in the passageway 74 and the centering bearing 72 may
translate towards the proximal end as the core is received in the
passageway 74.
[0037] As the drill bit 60 is advanced through the excision
passageway 28a in the first guide 20, a portion of the cutting
surface 66 may engage the tibial articular surface 12 and/or the
bone 10, thereby forming a truncated cylindrical excision site.
Once the drill bit 60 has been advanced through the excision
passageway 28a to create the first excision site, the second
truncated cylindrical excision site may be formed. For example, the
second dowel 40b may be removed and a second drill bit 60 may be
advanced through the second excision passageway 28b in a manner
similar to that described herein. The first and second drill bits
60 may have the same or different outer diameters.
[0038] As discussed herein, the first and the second excision
passageways 28a, 28b may be offset relative to each other. Put
another way, the first and the second excision passageways 28a, 28b
may be separated by a distance generally perpendicular to the
longitudinal axes of the first and the second excision passageways
28a, 28b such that the first and the second truncated cylindrical
excision sites do not overlap.
[0039] FIG. 8 generally illustrates one embodiment of the first and
the second truncated cylindrical excision sites 80a, 80b
corresponding to the drill bit 60 and the first and the second
excision passageways 28a, 28b. As can be seen, a center section 81
of articular surface 12/bone 10 remains separating the first and
the second truncated cylindrical excision sites 80a, 80b. This
center section 81 may optionally be removed using second guide/jig
82.
[0040] The second guide 82 may comprise one or more alignment
passageways 83a, 83b as well as a third excision passageway 28c
extending through the body portion 85. The third excision
passageway 28c may also define a generally cylindrical core pathway
for a drill bit. Once the first and the second truncated
cylindrical excision sites 80a, 80b have been formed, the first
guide 20 and pins 32a, 32b may be removed and pins 48a, 48b may
remain secured to the bone 10. The second guide 82 may then be
advanced over the pins 48a, 48b to align the second guide 82 (and
in particular the third excision passageway 28c) relative to the
articular surface 12 and the center section 81. Optionally, the
second guide 82 may feature protrusions 84a, 84b configured to be
at least partially received in the first and the second truncated
cylindrical excision sites 80a, 80b to further align and secure the
position of the second guide 82 and the third excision passageway
28c relative to the articular surface 12/center section 81. The
second guide 82 may therefore be advanced along the pins 48a, 48b
and the protrusions 84aa, 84b may be received into the first and
the second truncated cylindrical excision sites 80a, 80b until at
least a portion of the distal face 86 of the second guide 82
generally abuts against the bone 12 and a projection of the third
core pathway associated with the third excision passageway 28c
partially intersects with the center section 81.
[0041] Once the second guide 82 is aligned with the first and
second excision sites 80a, 80b and the pins 48a, 48b, a third drill
60 may be advanced through the third excision passageway 28c
extending through the body 85 to remove the center section 81 and
form the third truncated cylindrical excision site 80c as generally
illustrate in FIG. 9. The third excision passageway 28c may be
configured to align the third drill 60 such that the resulting
third truncated cylindrical excision site 80c partially overlaps
with the first and the second truncated cylindrical excision sites
80a, 80b. For example, the third excision passageway 28c may have a
diameter which would partially overlap with the first and the
second excision passageways 28a, 28b if the three excision
passageways 28a-28c were transposed on each other and aligned with
the pins 48a, 48b.
[0042] The resulting implant site may therefore comprise the first,
second, and third truncated cylindrical excision sites 80a-80c
wherein the first and the second truncated cylindrical excision
sites 80a, 80b partially overlap with the third truncated
cylindrical excision site 80c. The truncated cylindrical excision
sites 80a-80c may be centered/revolved around the pins 48a, 48b,
32b and may extend along the articular surface 12 generally along
the anterior-posterior plane. For example, the truncated
cylindrical excision sites 80a-80c may extend from the anterior
face of the tibial articular surface 12 generally towards the
posterior face. The implant site may therefore include a base
portion 90 comprising three overlapping truncated cylindrical
extensions or scallops defined by the three excision passageways
28a-28c. The resulting implant site therefore may generally
eliminate/reduce the occurrence of 90 degree cuts and therefore
more evenly distribute loads/forces to the bone 10 compared a
traditional 90 degree notch cut.
[0043] The truncated cylindrical excision sites 80-80c have been
illustrated extending partially across the tibial articular surface
12 (i.e., one or more of the truncated cylindrical excision sites
80-80c do not extend completely across the articular surface 12
thus leaving a portion 99 of the tibial articular surface 12 and/or
bone 10 remaining). This embodiment may be particularly beneficial
since it further minimizes the potential for accidentally damaging
the nerve bundle. However, the system and method according to the
present disclosure may also allow for one or more of the truncated
cylindrical excision sites 80a-80c to extend completely across the
articular surface 12 as generally illustrate in FIG. 10. In
particular, the system and method according to the present
disclosure may be able to accurately enough form the truncated
cylindrical excision sites 80a-80c to minimize the potential of
damaging the nerve bundle to an acceptable level.
[0044] While the system and method has been described having a
first and a second guide 20, 82, the system and method may utilize
a single guide. For example, the first guide 20 may include
alignment dowels (not shown) configured to be advanced and/or
secured within the first and second excision passageways 28a, 28b.
The alignment dowels may include protrusions 84a, 84b configured to
engage the first and second truncated excision sites 80a, 80b as
generally described herein. In addition, the guide 20 may include a
third excision passageway 28c extending generally along the locking
passageway 34b (which itself may be formed in a removable bushing).
The alignment dowels may have an outer shape such that the third
excision passageway 28c defines a generally cylindrical core
pathway for the drill 60.
[0045] Turning now to FIG. 11, one embodiment of an implant 100
consistent with the present disclosure is generally illustrated.
The implant 100 may comprise a load bearing surface 102 and a bone
facing or distal surface 104. The load bearing surface 102 may have
a surface contour/geometry substantially corresponding to the
contour/geometry of the removed tibial articular surface 12
proximate the defect 13. The contour/geometry of the load bearing
surface may be based on a plurality of measurement take of the
patient's tibial articular surface 12, for example, as described in
U.S. patent application Ser. No. 10/373,463, filed on Feb. 24,
2003, entitled System and Method for Joint Resurface Repair, which
is fully incorporated herein by reference.
[0046] The bone facing surface 104 may have an overall
contour/geometry generally corresponding to the contour/geometry of
the base portion 90 of the three truncated cylindrical excision
sites 80a-80c and the removed bone 10. Optionally, the bone facing
surface 104 may include one or more relief cavities, pockets and/or
cross-cuts 106 configured to enhance securing the implant 100 to
the bone 10 within the truncated cylindrical excision sites
80a-80c. The relief cavities 106 may be configured to allow bone
regrowth around a portion of the implant 100 and/or promote cement
adhesion. As shown, the implant 100 may comprise a generally
unitary structure (i.e., the implant 100 may be a solid, one-piece
component). For example, the implant 100 may be made from
ultra-high molecular weight polyethylene (UHMWPE).
[0047] Turning now to FIG. 12, a cross-sectional view of another
embodiment of an implant 100b consistent with the present
disclosure is generally illustrated. Implant 100b may comprise
multiple portions configured to be coupled together, for example,
an upper and a lower portion 110, 112. The upper portion 110 may
include a load bearing surface 102 as described herein while the
lower portion 112 may comprise a bone facing surface 104 as
described herein. The upper and lower portions 110, 112 may be
configured to be coupled together. For example, the lower portion
112 may be based on the guides 20, 82 used to form the truncated
cylindrical excision sites 80a-80c while the upper portion 110 may
be based on the contour/geometry of the patient's removed articular
surface 12. Put another way, the lower portion 112 may be
considered "generic" or common in that it is based on the guides
20, 82 rather than measurements of the patient's articular surface
12 while the upper portion 110 may be selected based specifically
on measurements of the patient's articular surface 12.
[0048] Turning now to FIG. 13, a cross-sectional view of another
implant 100c is shown generally implanted within the implant site
120 formed by truncated cylindrical excision sites 80a-80c. As
shown, the bone facing surface 104 of the implant 100c may be
generally disposed along the base portion 90 of the truncated
cylindrical excision sites 80a-80c while the load bearing surface
102 may be substantially continuous with the surrounding tibial
articular surface 12 (i.e., the tibial articular surface 12
adjacent to and abutting the implant 100c). The implant 100c may
optionally comprise one or more keels, tails, protrusions or the
like 122. The keel 122 may extend generally downwardly from the
bone facing surface 104 and away from the load bearing surface 102.
The keel 122 may be configured to engage a corresponding notch 124
formed in the base portion 90 of the truncated cylindrical excision
sites 80a-80c. While the implant 100c is illustrated having an
upper and a lower portion 110, 112, the implant 100 as illustrated
in FIG. 11 may optionally include one or more keels 122. The keel
122 may be an integral component of the implant 100 or the lower
portion 112 or alternatively may be a separate component coupled
thereto.
[0049] As may be appreciated from FIGS. 11-13, an implant
consistent with at least one embodiment of the present disclosure
may have a load bearing surface 102 which is non-planar. While
traditional tibial implants have had a generally planar or flat
load bearing surface, an implant consistent with at least one
embodiment of the present disclosure may have a concaved geometry
which may better approximate the geometry of the patient's removed
tibial articular surface 12. For example, the implant as shown in
FIG. 13 may have a first side (e.g., but not limited to, a medial
side) having a height L less than a height H of a second side
(e.g., but not limited to, the lateral side).
[0050] Turning now to FIG. 14, a top view of one embodiments of the
implant 100 consistent with the present disclosure is generally
illustrated. When viewed from the top side (i.e., when viewing the
load bearing surface 102), the implant 100 may have a generally "D"
shape. This "D" shape may correspond to an implant site which
extends all the way cross the anterior-posterior plane of the
articular surface (e.g., as generally shown in FIG. 10). As shown
in FIG. 15, the implant 100 may also have a modified or notched "D"
shape. In particular, the implant 100 may include a notched region
130 which may correspond to the area 99 of the tibial articular
surface 12 proximate to the posterior face of the tibia 10 which is
not removed (e.g., as generally shown in FIG. 9). As discussed
herein, leaving this portion 99 of the tibial articular surface 12
and/or bone 10 intact may minimize the potential of damaging the
nerve bundle 16 (FIG. 1).
[0051] According to one aspect, the present disclosure features an
implant resection system for preparing an implant site to replace a
defect in an articular surface of a first bone. The implant
resection system includes a guide configured to be coupled
generally perpendicular to the first bone proximate to the defect.
The guide includes a body portion defining a plurality of excision
passageways. The excision passageways each define a generally
cylindrical core pathway configured to extend generally
perpendicular to the first bone which partially overlaps with an
adjacent generally cylindrical core pathway. A projection
associated with each of the plurality of the generally cylindrical
core pathways defines a truncated cylindrical excision site
extending through a portion of the articular surface. Each
truncated cylindrical excision site partially overlaps with at
least one adjacent truncated cylindrical excision site.
[0052] According to another aspect, the present disclosure features
a method for preparing an implant site to replace a defect in an
articular surface. The method includes securing a guide to bone
proximate the defect. The guide includes a body portion defining a
plurality of excision passageways. Each excision passageway defines
a generally cylindrical core pathway which partially overlaps with
an adjacent generally cylindrical core pathway. The method further
includes advancing at least one drill through the plurality of
excision passageways along the generally cylindrical core pathways
to form a plurality of partially overlapping truncated cylindrical
excision sites extending through the articular surface.
[0053] While the principles of the present disclosure have been
described herein, it is to be understood by those skilled in the
art that this description is made only by way of example and not as
a limitation as to the scope of the invention. The features and
aspects described with reference to particular embodiments
disclosed herein are susceptible to combination and/or application
with various other embodiments described herein. Such combinations
and/or applications of such described features and aspects to such
other embodiments are contemplated herein. Other embodiments are
contemplated within the scope of the present invention in addition
to the exemplary embodiments shown and described herein.
Modifications and substitutions by one of ordinary skill in the art
are considered to be within the scope of the present invention,
which is not to be limited except by the following claims.
[0054] All definitions, as defined and used herein, should be
understood to control over dictionary definitions, definitions in
documents incorporated by reference, and/or ordinary meanings of
the defined terms.
[0055] The indefinite articles "a" and "an," as used herein in the
specification and in the claims, unless clearly indicated to the
contrary, should be understood to mean "at least one."
[0056] The phrase "and/or," as used herein in the specification and
in the claims, should be understood to mean "either or both" of the
elements so conjoined, i.e., elements that are conjunctively
present in some cases and disjunctively present in other cases.
Other elements may optionally be present other than the elements
specifically identified by the "and/or" clause, whether related or
unrelated to those elements specifically identified, unless clearly
indicated to the contrary.
[0057] All references, patents and patent applications and
publications that are cited or referred to in this application are
incorporated in their entirety herein by reference.
[0058] Additional disclosure in the format of claims is set forth
below.
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