U.S. patent application number 13/156246 was filed with the patent office on 2012-01-19 for implant components and methods.
This patent application is currently assigned to SMITH & NEPHEW, INC.. Invention is credited to Jeffrey A. Sharp.
Application Number | 20120016485 13/156246 |
Document ID | / |
Family ID | 45098648 |
Filed Date | 2012-01-19 |
United States Patent
Application |
20120016485 |
Kind Code |
A1 |
Sharp; Jeffrey A. |
January 19, 2012 |
IMPLANT COMPONENTS AND METHODS
Abstract
Systems, devices, and methods are provided for orthopedic
implants. The implants may include a base member, such as an
acetabular shell or an augment, that is configured to couple with
an augment, flange cup, mounting member, or any other suitable
orthopedic attachment. An implant component may be expandable to
allow for adjustment and custom fitting during implantation. An
expandable implant may have a first portion and a second portion
separated by a slit. An expansion member can be disposed between
the first and second portions and can be actuated to displace the
two portions relative to each other, increasing the size of the
implant. Any number of slits and expandable sections can be
included in the implant to provided more flexibility in the
expansion of the implant.
Inventors: |
Sharp; Jeffrey A.; (Salt
Lake City, UT) |
Assignee: |
SMITH & NEPHEW, INC.
Cordova
TN
|
Family ID: |
45098648 |
Appl. No.: |
13/156246 |
Filed: |
June 8, 2011 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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61352705 |
Jun 8, 2010 |
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61352722 |
Jun 8, 2010 |
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61422903 |
Dec 14, 2010 |
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61466817 |
Mar 23, 2011 |
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Current U.S.
Class: |
623/22.21 ;
606/91 |
Current CPC
Class: |
A61B 17/866 20130101;
A61F 2/30942 20130101; A61F 2/4609 20130101; A61F 2002/3092
20130101; A61F 2002/30387 20130101; A61F 2002/30462 20130101; A61F
2002/30579 20130101; A61F 2002/3429 20130101; A61F 2002/30891
20130101; A61F 2002/4615 20130101; A61F 2002/30617 20130101; A61F
2002/30449 20130101; A61F 2002/3441 20130101; A61F 2002/30538
20130101; A61F 2002/30507 20130101; A61F 2002/3082 20130101; A61F
2002/30189 20130101; A61F 2002/30985 20130101; A61F 2/34 20130101;
B33Y 80/00 20141201; A61F 2002/30011 20130101; A61F 2002/30326
20130101; A61F 2002/30578 20130101; A61B 17/8685 20130101; A61F
2002/4619 20130101; A61F 2/30734 20130101; A61F 2002/30169
20130101; A61F 2002/3487 20130101; A61F 2002/30471 20130101; A61B
17/8066 20130101; A61F 2002/30604 20130101; A61F 2002/30331
20130101; A61B 17/82 20130101; A61F 2002/30841 20130101; A61F
2002/3096 20130101; A61F 2002/348 20130101; A61F 2002/30736
20130101; A61F 2002/3412 20130101; A61F 2/30749 20130101; A61F
2002/3448 20130101; A61F 2002/30952 20130101; A61F 2002/3093
20130101; A61F 2/30771 20130101; A61F 2/30965 20130101; A61F
2/30907 20130101; G06F 9/45533 20130101; A61F 2002/30474
20130101 |
Class at
Publication: |
623/22.21 ;
606/91 |
International
Class: |
A61F 2/34 20060101
A61F002/34; A61B 17/56 20060101 A61B017/56 |
Claims
1. An orthopedic implant comprising: an acetabular implant having a
first portion and a second portion, the first and second portions
being separated along a first side of the implant by a slit; and an
expansion member disposed between the first and second portions,
the expansion member being adjustable by a tightening tool to
displace the two portions relative to each other.
2. The orthopedic implant of claim 1, further comprising a hinge
that joins the first and second portions along a second side of the
implant.
3. The orthopedic implant of claim 2, wherein the implant is a
flange that is connected to an acetabular shell.
4. The orthopedic implant of claim 1, wherein the expansion member
is a shaped memory plug or a screw.
5. The orthopedic implant of claim 4, wherein the implant is an
augment with a curved side and a connection site that attaches to
an acetabular shell.
6. The orthopedic implant of claim 1, wherein the implant is an
acetabular shell or cage.
7. The orthopedic implant of claim 1, further comprising a screw
that passes through the implant to connect the implant to the
patient's acetabulum.
8. The orthopedic implant of claim 1, wherein the first and second
portions, proximate the slit, comprise a solid portion.
9. The orthopedic implant of claim 8, wherein the volume of the
acetabular implant not including the solid portion comprises a
porous portion.
10. The orthopedic implant of claim 1, further comprising
intersecting slits perpendicular to the slit for dividing the
augment into a plurality of portions.
11. A method of implanting an orthopedic device in a patient's
joint, comprising: installing an acetabular shell or cage within
the joint; placing an augment between the shell and the patient's
bone; expanding two portions of the augment until a first portion
abuts the patient's bone and a second portion abuts the acetabular
shell or cage; and anchoring the augment to the bone.
12. The method of claim 11, wherein the expanding comprises using a
tightening tool coupled to an expansion member disposed between the
two portions of the augment to displace the two portions relative
to each other.
13. The method of claim 12, wherein the expansion member is a
shaped memory plug or a screw.
14. The method of claim 12, wherein the expansion member is a
wedge.
15. The method of claim 12, wherein the tightening tool includes a
torque-limiting device.
16. The method of claim 11, further comprising expanding the two
portions of the augment along a hinge that joins the first and
second portions.
17. The method of claim 11, further comprising passing a screw
through the shell to connect the shell to the patient's
acetabulum.
18. The method of claim 11, further comprising applying a porous
surface to a portion of the augment.
19. The method of claim 11, wherein the two portions of the augment
are biased toward one another.
20. The method of claim 11, further comprising removing the augment
via slits or flexible hinge portions provided thereon.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S Provisional
Patent Application No. 61/352,705, filed Jun. 8, 2010, U.S.
Provisional Application No. 61/352,722, filed Jun. 8, 2010, U.S.
Provisional Application No. 61/422,903, filed Dec. 14, 2010, and
U.S. Provisional Application No. 61/466,817, filed Mar. 23, 2011,
which are hereby incorporated by reference herein in their
entireties.
BACKGROUND
[0002] Joints often undergo degenerative changes due to a variety
of reasons. When joint degeneration becomes advanced or
irreversible, it may become necessary to replace the natural joint
with a prosthetic joint. Artificial implants, including hip joints,
shoulder joints, and knee joints are widely used in orthopedic
surgery. Specifically, hip joint prostheses are common. The human
hip joint acts mechanically as a ball and socket joint, wherein the
ball-shaped head of the femur is positioned within the
socket-shaped acetabulum of the pelvis. Various degenerative
diseases and injuries may require replacement of all or a portion
of a hip using synthetic materials, typically metals, ceramics, or
plastics.
[0003] More particularly, natural hips often undergo degenerative
changes, requiring replacement of the hip joint with a prosthetic
joint. Often, the hip is replaced with two bearing surfaces between
the femoral head and the acetabulum. The first bearing surface is
typically a prosthesis shell or acetabular cup, which may be formed
of metal, ceramic material, or as otherwise desired. A liner
(conventionally formed of polyethylene material such as ultra high
molecular weight polyethylene, a ceramic material, or in some
cases, even a metal liner) is then fit tightly within the shell to
provide an inner bearing surface that receives and cooperates with
an artificial femoral head in an articulating relationship to track
and accommodate the relative movement between the femur and the
acetabulum.
[0004] The cup (or a cup and liner assembly) is typically fixed
either by placing screws through apertures in the cup or by
securing the cup with cement. In some cases, only a liner is
cemented in a patient due to poor bone stock. In other cases, a cup
having a porous surface may be press fit into the reamed acetabular
surface.
[0005] It may become necessary to conduct a second or subsequent
surgery in order to replace a prosthetic joint with a (often
larger) replacement joint. Such surgeries often become necessary
due to further degeneration of bone or advancement of a
degenerative disease, requiring removal of further bone and
replacement of the removed, diseased bone with a larger or enhanced
prosthetic joint, often referred to as a revision prosthesis. For
example, bone is often lost around the rim of the acetabulum, and
this may provide less rim coverage to securely place a press-fit
cup. Such surgeries may thus be referred to as revision
surgeries.
[0006] In acetabular revision surgery, an acetabular prosthesis
generally includes additional mounting elements, such as augments,
flanges, hooks, plates, or any other attachment or mounting points
or members that provide additional support and/or stability for the
replacement prosthesis once positioned. These additional mounting
or attachment members are often required due to bone degeneration,
bone loss, or bone defects in the affected area (in this instance,
the hip joint).
[0007] Various types of these mounting members (which term is
intended to include but not be limited to flanges, blades, plates
and/or hooks) may be provided in conjunction with a prosthesis
system in order to help the surgeon achieve optimal fixation,
non-limiting examples of which include iliac flanges (providing
securement and fixation in and against the ilium region of the
pelvis), ischial blades (providing securement and fixation in and
against the ischium), and obturator hooks (providing securement and
inferior fixation by engaging the obturator foramen). Although
there have been attempts to provide such mounting attachments with
modularity, the solutions to date have generally fallen short of
providing true modularity. Instead, they typically provide a few
discrete positions at which the mounting members may be positioned,
without providing the surgeon a fuller range of decision
options.
[0008] Additionally, in some primary surgeries and more often in
revision surgeries, the acetabulum may have a bone defect or void
that the surgeon must fill with bone grafts before inserting a new
shell. This can be time consuming and expensive, and may subject
the patient to additional health risks. Some techniques use an
augment in connection with the acetabular shell, which can be
coupled to or otherwise attached to the outer surface of the
shell.
[0009] With current augments, the surgeon can attach the augment to
the bone and then implant the cup. However, many acetabular shells
rely on bone screws to achieve proper fixation and the augment
often gets in the way of a screw. In short, surgeons need the
freedom to place screws in the best location, but this compromises
their ability to use augments. With current systems, it also takes
an increased amount of time surgical time to trial the component
orientation and then try to find good bone fixation for the cup.
The surgeon will often have to free-hand the amount of bone removed
while estimating the size of augment needed. In the cases where
bone is often deficient, surgeons are hesitant to take away any
more bone than necessary.
[0010] Various additional features and improved features intended
for use and application with various types of joint implants are
also described herein, such as improved bone screws, improved
coatings, and various augment removal and insertion options.
SUMMARY
[0011] Disclosed herein are systems, devices, and methods for
providing modular orthopedic implants. The implants may include a
base member, such as an acetabular shell or an augment, that is
configured to couple with an augment, flange cup, mounting member,
any other suitable orthopedic attachment, or any combinations
thereof. Mounting members include, for example, flanges, blades,
hooks, and plates. In some embodiments, the orthopedic attachments
may be adjustably positionable about the base member or other
attachments thereby providing modularity for assembling and
implanting the device. Various securing and/or locking mechanisms
may be used between the components of the implant. In certain
embodiments, the orthopedic attachments are removably coupled to
the base member or other components. In certain embodiments, the
orthopedic attachments are integrally provided on the base member
or other components, yet may still be adjustably positionable
thereabout. In some embodiments, expandable augments, base members,
or other bone filling devices are provided. In some embodiments,
surface features are provided that create friction and allow for
surrounding bone ingrowth at the interface of the implants and a
patient's bone.
[0012] Systems, devices, and methods described herein provide
implants that can be expanded or adjusted to fill bone voids in a
patient's anatomy surrounding the implant. In certain embodiments,
an orthopedic implant includes an acetabular implant with first and
second portions that are separated along a side of the implant by a
slit and an expansion member disposed between the first and second
portions and adjustable by a tightening tool to displace the two
portions relative to each other. The implant may also include a
hinge that joins the first and second portions along a side of the
implant. The first and second portions of an implant may comprise a
solid portion, and the volume of the implant not including the
solid portion may be porous. Any number of portions may be provided
in the implant, and the implant may have any number of intersecting
perpendicular slits for dividing the portions. The implant may be a
flange connected to an acetabular shell, or may be an acetabular
shell or cage. The implant may include a screw that passes through
the implant to connect the implant to a patient's acetabulum.
[0013] In certain embodiments, an expansion member used in an
expandable or adjustable implant may be a shaped memory plug or a
screw. The expansion member may be an augment with a curved side
and a connection site that attaches to an acetabular shell.
[0014] In certain embodiments, an orthopedic device is implanted in
a patient's joint by installing an acetabular shell or cage within
the joint and placing an augment between the shell and the
patient's bone. Two portions of the augment are expanded until a
first portion abuts the patient's bone and a second bone abuts the
acetabular shell or cage, and the augment is anchored to the bone.
The portions of the augment may be expanded using a tightening tool
coupled to an expansion member disposed between the portions of the
augment to displace the portions relative to each other. The
expansion member used may be a shaped memory plug, a screw, or a
wedge, and the tightening tool may include a torque-limiting
device. The two portions of the augment may be expanded along a
hinge that joins the portions. The portions of the augment may be
biased towards one another. A screw may be passed through the shell
to connect the shell to the patient's acetabulum. A porous surface
may be applied to a portion of the augment. The augment may be
removed via slits or flexible hinge portions provided on the
augment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] The foregoing and other objects and advantages will be
apparent upon consideration of the following detailed description,
taken in conjunction with the accompanying drawings, in which like
reference characters refer to like parts throughout, and in
which:
[0016] FIGS. 1-5 show illustrative expandable/adjustable
augments;
[0017] FIG. 6 shows an illustrative expansion member;
[0018] FIGS. 7-11 show illustrative expandable/adjustable
augments;
[0019] FIG. 12 shows an illustrative expandable/adjustable augment
with multiple expansion screws;
[0020] FIG. 13 shows an illustrative expandable/adjustable implant
shell; and
[0021] FIG. 14 shown an illustrative augment having recess portions
alongside a split portion.
DETAILED DESCRIPTION
[0022] To provide an overall understanding of the systems, devices,
and methods described herein, certain illustrative embodiments will
be described. Although the embodiments and features described
herein are specifically described for use in connection with
acetabular systems, it will be understood that all the components,
connection mechanisms, adjustable systems, fixation methods,
manufacturing methods, coatings, and other features outlined below
may be combined with one another in any suitable manner and may be
adapted and applied to medical devices and implants to be used in
other surgical procedures, including, but not limited to: spine
arthroplasty, cranio-maxillofacial surgical procedures, knee
arthroplasty, shoulder arthroplasty, as well as foot, ankle, hand,
and other extremity procedures.
[0023] Various implants and other devices described herein in their
various embodiments may be used in conjunction with any appropriate
reinforcement material, non-limiting examples of which include bone
cement, appropriate polymers, resorbable polyurethane, and/or any
materials provided by PolyNovo Biomaterials Limited, or any
suitable combinations thereof Further non-limiting examples of
potential materials that may be used are described in the following
references: U.S. Patent Application Publication No. 2006/0051394,
entitled "Biodegradable Polyurethane and Polyurethane Ureas," U.S.
Patent Application Publication No. 2005/0197422, entitled
"Biocompatible Polymer Compositions for Dual or Multi Staged
Curing," U.S. Patent Application Publication No. 2005/0238683,
entitled "Biodegradable Polyurethane/Urea Compositions," U.S.
Patent Application Publication No. 2007/0225387, entitled "Polymer
Compositions for Dual or Multi Staged Curing," U.S. Patent
Application Publication No. 2009/0324675, entitled "Biocompatible
Polymer Compositions," U.S. Patent Application Publication No.
2009/0175921, entitled "Chain Extenders," and U.S. Patent
Application Publication No. 2009/0099600, entitled "High Modulus
Polyurethane and Polyurethane/Urea Compositions." Each of the prior
references is incorporated by reference herein in its entirety.
[0024] Referring now to FIGS. 1-13, there are some instances during
hip arthroplasty when an expandable augment or expandable shell
implant may be desired. Initial fixation during hip arthroplasty is
important, but the shapes of conventional augments may not be ideal
and conventional bone preparation for receiving shaped augments and
shells may not be precise. For example, hand-reaming is typically
used to prepare an affected area of bone and create a shaped void
for receiving an augment or shell. Although surgeons try not to
remove more bone than necessary, in some instances, the surgeon may
unintentionally create a slightly larger opening or an oblong void
that does not precisely fit the shape of outer surfaces of an
augment or shell to be implanted. Moreover, poor bone quality may
affect the press fit and/or total interference between bone and an
augment or shell even if the bone is well-shaped to fit external
geometries of the augment or shell. Cement, allograft, and bone
pastes have been used in the past to fill in the gaps between
augments, bone, and implants. However, FIGS. 1-13 show several
embodiments of augments, shells, and/or mounting members that may
be expanded to compensate for poor bone quality or non-precise bone
preparation (e.g., over-reaming). The augments, shells, and/or
mounting members are preferably manufactured by a rapid
manufacturing method (e.g., stereolithography, 3D-printing,
selective laser sintering (SLS), electron beam welding (EBM),
etc.). The augments, shells, and/or mounting members may also be
machined or casted from a bulk material and then plasma-sprayed or
otherwise coated with a surface texture or porous ingrowth
structure. They may have a generally porous outside for contact
with bone, and may have one or more non-porous external or internal
surfaces and volumes for attaching to implants or improving
strength and flexibility of the augments, shells, and/or mounting
members.
[0025] The expandable augments, mounting members, or other
implants, including shells and cages, have at least first and
second portions that are connected, for example, by a soft or
adjustable hinge portion or by a wire fixation or other suitable
means, and the connections allow for separation of the portions.
The separation is controlled by actuating an expansion member
disposed between the at least two portions. As shown in FIGS. 1-5,
an expansion member 1602, non-limiting examples of which may
include a wedge, fastener, mandrel, screw, or other component, is
inserted into an augment in order to expand the augment once it is
placed inside or adjacent to a prepared bone cavity. The expansion
member 1602 is actuatable, for example, by a surgical tightening
rod or driver. A torque wrench can be utilized to ensure that the
augment, shell, or mounting member has a proper interference or
"press-fit" with surrounding bone, without fracturing the bone.
Alternatively, as shown in the expansion member 1630 in FIG. 6, an
expansion member itself may comprise torque-limiting means such as
a frangible driver portion 1632 with a calibrated circumferential
notch or groove 1634 that is designed to shear off after a
specified torque is reached. By controlling the amount of torque
applied to an expansion member, a proper press fit and interference
with surrounding bone is achieved.
[0026] As shown in augments 1600, 1610, and 1620 in FIGS. 1-5, the
outer geometries, shape, or size of an augment may be initially
biased inwardly or undersized, and then expanded with an expansion
member, which may alternatively comprise or be provided by a shape
memory polymer or wedging action from a setscrew. For example, two
portions 1604 and 1606 of augment 1600 in FIG. 1 are initially
biased toward each other but are displaced away from each other
upon actuation of the expansion member 1602. An augment, shell, or
mounting member may have one or more flexible hinge portions, such
as hinge area 1608 of augment 1600 to create a fulcrum for two or
more other augment, shell, or mounting member portions to move in
relation with each other. The geometries or portions of the
augment, shell, or mounting member may also or alternatively be
connected by a wire, screw, staple, threaded expansion rod or other
structure, which holds the portions together but still allows them
to expand under actuation of the expansion member. Additionally or
alternatively, the augment or mounting member may have one or more
slit portions, such as slit 1609 of augment 1600, to allow for even
radial expansion. In certain embodiments, there may be a slit
portion, a cruciform, or any other appropriately shaped cut or
division in the augment, shell, or mounting member positioned a set
desired distance or a set angle from one another so that the
augment, shell, or mounting member portions expand evenly when one
or more expansion members are positioned.
[0027] In FIGS. 2 and 3, an augment is provided that has two
augment portions 1612 and 1614 separated by a slit 1616 and hinged
together by a flexible hinge portion 1618. It will be understood
that additional or fewer augment portions may be provided, and that
the portions may also be provided on one or more mounting members
and that the following description would be related thereto. The
flexible hinge portion 1618 allows the augment portions 1612 and
1614 to move away from each other upon insertion of an expansion
member 1602, which is shown as an expansion screw, but may be any
other type of expansion member, such as a wedge, a plug, a bone
screw, a set screw, a member having a smooth bore with a taper, a
shape memory plug, or any other component, which, in turn, expands
the entire augment. While not shown, one or more additional slits
and/or flexible hinge portions may be added to allow a more uniform
radial expansion.
[0028] The augment 1610 shown in FIGS. 2 and 3 may include one or
more porous portions to facilitate bone ingrowth into the augment.
For example, each of augment portions 1612 and 1614 may be porous.
All of augment 1610 may be porous for bone ingrowth, or some
portions of augment 1610 may be porous and some may be solid to
provide strength to augment 1610. It may be desirable to provide a
solid core in augment 1610 surrounded by porous outer portions to
provide needed strength at the interface between augment 1610 and
expansion member 1602 while still providing porous portions 1612
and 1614 for bone in growth. For example, the inner core of augment
1610 outlined by the dotted line in FIGS. 2 and 3 may be solid to
provide needed strength around expansion member 1602 while augment
portions 1612 and 1614 may be porous for ingrowth.
[0029] FIGS. 4 and 5 show an expandable augment 1620 that may be
implanted and expanded similar to augments 1600 and 1610 discussed
above in FIGS. 1-3. In particular, Augment 1620 includes two
portions 1622 and 1624 that move radially outward when expansion
member 1602 is inserted into augment 1620. Augment 1620 may be made
of a solid material with surface treatment, a porous material, or
may be a combination of solid and porous sections to provide both
strength and bone ingrowth for the augment. The dotted line in
FIGS. 4 and 5 may separate a solid core of augment 1620 that
surrounds the threaded hole for expansion member 1602 from a porous
peripheral portion of the augment, as discussed above with respect
to FIGS. 2 and 3. The solid and porous portions may be located and
separated within the augment in any suitable geometry, as shown in
the different solid and porous geometries in augment 1610 of FIGS.
2 and 3 and augment 1620 of FIGS. 4 and 5.
[0030] During replacement or revision surgery, a surgeon may use
any of the augments shown in FIGS. 1-5 to fill bone voids
surrounding an implant. Depending on the anatomy of a certain
patient and the surgical procedure, the augment may be placed into
a bone void either before or after an implant shell is inserted.
The augment may also be attached to the shell before implantation,
before expansion begins, or after the augment is expanded to its
final size. The surgeon positions the augment within the bone void
in a contracted state such that there is space in the bone void
that is not initially filled by the augment. The surgeon then
activates an expanding component of the augment, for example, by
turning a set screw with a surgical tool, to cause two or more
portions of the augment to expand. The surgeon expands the augment
until the augment fills substantially the entire bone void and
abuts both the implanted shell and the patient's bone. The augment
is then fixed in place, either by mechanical fasteners such as
screws or by allowing surrounding bone to grow into ingrowth
surfaces on the augment.
[0031] Because the augments, shells or mounting members shown and
disclosed in FIGS. 1-13 are slowly expanded in-situ within the
prepared bone void, impaction forces are avoided, but bone
interference and press-fit is still achieved. Moreover, the risks
of bone fracture, sitting too proud from a bone surface, and too
much bone interference/press-fit (all generally being associated
with impaction techniques) are mitigated or eliminated. It should
be noted that one advantage of the devices shown in FIGS. 1-13 is
that augments, shells, or mounting members may be more easily
removed during revision surgeries due to the slits and flexible
hinge portions provided thereon.
[0032] For example, in a revision hip surgery, a surgeon may first
remove the expansion member and then simply impact the augment,
shell, or mounting member radially-inwardly from a side portion to
fold the augment or mounting member, urging the augment or mounting
member portions towards each other and away from outer areas of
bone ingrowth. In another example, the one or more slits generally
"compartmentalize" the augment, shell, or mounting member into
several smaller outer ingrowth surface areas. Therefore, each
augment, shell, or mounting member portion may be removed
individually from well-fixed bone with greater ease than for a
well-fixed non-adjustable/expandable implant that may have an
entire outer solid surface that is well-fixed with bone ingrowth.
Lastly, slits may facilitate the entry of a saw blade, osteotome,
or other cutting tool (e.g., a Midas Rex.RTM. pneumatic tool by
Medtronic) for removing the augment, shell, or mounting member from
well-fixed bone. The threaded openings provided in the augment,
shell, or mounting member may be engaged by a threaded distal end
of a slap hammer tool for removal from well-fixed bone in a manner
similar to that used for hip stem removal during revision total hip
arthroplasty (THA).
[0033] FIG. 7 shows an expandable/adjustable augment 1640 related
to the embodiments described above and shown in FIGS. 1-6. The
augment 1640 may have any outer peripheral shape to accommodate
various bone voids and defects. While the entire augment 1640 may
be solid and simply surface textured to improve bone ingrowth
properties, volume portions of the expandable/adjustable augment
1640 may be fully porous. In FIG. 7, the augment 1640 comprises at
least two fully-porous volume portions 1642 and 1644 separated by a
solid portion 1646. The fully-porous volume portions 1642 and 1644
are movable with respect to each other. The solid portion 1646 may
extend all the way to an outer periphery of the augment 1640
proximate a hinge region 1648 as shown in order to better
distribute stresses and maintain the integrity of the struts and
nodes of the ingrowth structures contained within the fully-porous
volume portions 1642 and 1644. This design may help reduce cracks
and fatigue failure. As shown in dotted lines in FIG. 7, the
expandable/adjustable augments disclosed herein may comprise
additional intersecting slits to separate portions of the augment
into multiple portions, such as thirds, quarters, or any other
appropriate division.
[0034] An expansion member 1650, which may be any of the
above-described expansion members such as a screw, wedge, or plug,
may be inserted into the augment 1640 to expand the augment 1640 in
at least one direction, such as in a radial direction or a width. A
receiving portion 1652 may be provided on the expandable/adjustable
augment 1640 which receives the expansion member 1650, and is
generally complementary to the shape of the expansion member 1650.
For example while it may not be shown, either the expansion member
1650 or the receiving portion 1652 may be tapered, undersized,
oversized, threaded, shim or wedge-shaped, threaded, smooth,
symmetrical, non-symmetrical, conical, cylindrical, concentric,
eccentric, and may be provided with various cross-sectional
geometries, non-limiting examples of which are shown in FIGS. 8 and
9. In some non-limiting examples, the expansion member 1650 may
comprise a screw, a quarter-turn fastener, a shape-memory plug, a
wedge, or a settable or injectable material such as an injectable
polyurethane, or packed graft material.
[0035] FIGS. 8 and 9 show non-limiting examples of a wedge
expansion member for use with expandable/adjustable augments and
mounting members disclosed herein. FIG. 8 shows a locking wedge
1690, and FIG. 9 shows a locking pin 1692 with a removal head 1694,
which, when inserted into a recess of an expandable/adjustable
augment or mounting member, may keep the augment or mounting member
in a desired expanded state. The wedge expansion member shown in
either FIG. 8 or 9 may be inserted at different depths within the
expandable/adjustable augment to expand or contract the
expandable/adjustable augment or flange to different diameters or
peripheral shapes.
[0036] FIG. 10 shows an expandable/adjustable augment 1660 that is
similar to the ones shown in FIGS. 1-7, incorporating a tapered
plug expansion member 1662. The tapered plug expansion member 1662
may have an inclined or otherwise tapered outer surface that wedges
against a complementary inclined or otherwise tapered inner surface
provided within the body of the expandable/adjustable augment
1660.
[0037] FIG. 11 shows an expandable augment 1670 similar to the one
shown in FIG. 10, wherein expansion of the augment 1670 is
controlled by the turning of one or more positioning screws 1672.
An upper plate member 1674 having an expansion member 1676 provided
thereon is placed on top of an expandable augment portion. As the
positioning screws 1672 are introduced and tightened, the upper
plate member 1674 moves closer to the augment 1670, and the
expansion member 1676 moves into a receiving portion 1678 located
adjacent an expandable region in the augment 1670 to bulge the
augment 1670 radially-outwardly.
[0038] FIG. 12 illustrates an expandable/adjustable augment 1680
similar to the ones shown in FIGS. 1-11, wherein expansion of the
augment 1680 is controlled by the turning of multiple expansion
screws 1682. The augment 1680 may be configured to expand by
different amounts in different regions of the augment 1680. A
plurality of slots 1684 may split the augment 1680 into several
portions that are moveable relative to each other. The
expandable/adjustable augment 1680 may be used to secure a press
fit around its entire perimeter even if a surgeon wobbles a reamer,
or if the bone void is prepared with a slightly different shape
and/or size than the undeformed expandable/adjustable augment
1680.
[0039] FIG. 13 shows an expandable/adjustable implant shell 1700
that provides an implant having an adjustable size to allow for
precise fit to a reamed bone void, similar to the expandable and
adjustable augments discussed with respect to FIGS. 1-12. The shell
1700 has a threaded hole 1704 that receives an expansion member
1702. Expansion member 1702 may be a mandrel, screw, wedge, plug,
or any other suitable expanding component. Depending on the
expansion member used, threaded hole 1704 may be replaced by a
non-threaded hole and may have any shape or contour needed to
receive expansion member 1702 and cause the shell 1700 to expand.
The shell 1700 has slits 1706 cut into shell 1700 to allow for
flexibility needed to expand the shell. The slits 1706 create
multiple segments 1708 around the shell that can be forced outward
for expansion. Any number of slits 1706 and segments 1708 may be
used to provide the desired amount of flexibility and expansion. As
expansion member 1702 is placed into the shell 1700, for example,
by a surgeon manually screwing expansion member 1702 into threaded
hole 1704, the shell 1700 expands as segments 1708 are forced
radially outwards, increasing the profile of the shell 1700 and
allowing the shell 1700 to fill surrounding bone voids.
[0040] Expandable and adjustable augments may also be used to
facilitate removal of the augments in revision surgeries. Implant
shells occasionally require revision surgery due to wear of the
implant or changes in a patient's anatomy, and revision surgeries
to improve the implants may involve removing augments as well as
implanted shells. An expanding augment that is used to fill a
patient's bone void can make the removal process easier by allowing
a surgeon to reverse the expansion and return the augment to its
contracted state for quick removal. A modified expandable augment
that provides for convenient removal is shown in FIG. 14.
[0041] FIG. 14 shows an augment 1240 that may be provided with
recess portions 1242, which, in this embodiment, are shown
alongside a split portion 1244, but which can be provided anywhere
on the augment 1240, or even on augments not having a split
portion. Recess portions 1242 are configured to receive a clamp or
other instrument 1246. Recess portions 1242 may be curved or
otherwise shaped to correspond to the instrument to be used. For
removal of the augment 1240, arms 1248 of the instrument 1246 may
be inserted into recess portions 1242 in order to securely grasp
the augment 1240, squeeze the augment 1240, and pull the augment
1240 from bone. The mechanical advantage of the clamp 1246 causes
the augment 1240 to squeeze or shut slightly or otherwise flex
inwardly, particularly in split augment embodiments, so that the
augment 1240 may be removed, even if well fixed in bone.
[0042] The split augment 1240 shown may move from a first position,
shown as the outer boundary 1250 in solid lines, to a second
compressed position, shown in dotted lines 1252 in a direction
shown by inward arrows 1254. This compression allows removal of the
augment 1240 in a relatively easier and more efficient manner than
chipping away at the augment 1240 or cutting the augment 1240 out
in separate portions with a blade.
[0043] Recess portions 1242 and instrument 1246 may also be used to
initially position or introduce the augment 1240 into a bone void.
Once positioned, an expansion member, such as any of the expansion
members shown and described herein, may be used to expand and lock
the augment 1240 into place. Although not shown, it may be
desirable to insert plugs or any other appropriate recess portion
cover to prevent bone ingrowth therein. Alternatively, bone graft
material or injectable polymers or any other filler material may be
inserted into recess portions, particularly if recess portions are
to be used solely for insertion and are not envisioned for use in
subsequent removal.
[0044] The foregoing is merely illustrative of the principles of
the disclosure, and the systems, devices, and methods can be
practiced by other than the described embodiments, which are
presented for purposes of illustration and not of limitation. It is
to be understood that the systems, devices, and methods disclosed
herein, while shown for use in acetabular systems, may be applied
to medical devices to be used in other surgical procedures
including, but not limited to, spine arthroplasty,
cranio-maxillofacial surgical procedures, knee arthroplasty,
shoulder arthroplasty, as well as foot, ankle, hand, and
extremities procedures.
[0045] Variations and modifications will occur to those of skill in
the art after reviewing this disclosure. The disclosed features may
be implemented, in any combination and subcombinations (including
multiple dependent combinations and subcombinations), with one or
more other features described herein. The various features
described or illustrated above, including any components thereof,
may be combined or integrated in other systems. Moreover, certain
features may be omitted or not implemented.
[0046] Examples of changes, substitutions, and alterations are
ascertainable by one skilled in the art and could be made without
departing from the scope of the information disclosed herein. All
references cited herein are incorporated by reference in their
entirety and made part of this application.
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