U.S. patent application number 13/736614 was filed with the patent office on 2013-07-11 for porous metal implants with bone cement.
This patent application is currently assigned to Zimmer, Inc.. The applicant listed for this patent is Timothy A. Hoeman, Matthew E. Monaghan. Invention is credited to Timothy A. Hoeman, Matthew E. Monaghan.
Application Number | 20130178947 13/736614 |
Document ID | / |
Family ID | 47628446 |
Filed Date | 2013-07-11 |
United States Patent
Application |
20130178947 |
Kind Code |
A1 |
Monaghan; Matthew E. ; et
al. |
July 11, 2013 |
POROUS METAL IMPLANTS WITH BONE CEMENT
Abstract
An orthopaedic implant for filling a bone void and a method of
using the same. The orthopaedic implant comprises an open porous
metal portion and a bone cement portion. At a first surface region,
the open porous metal portion facilitates bone and/or soft tissue
ingrowth into the pores of the first surface region of the open
porous metal. At a second surface region, the open porous metal
facilitates reception of the bone cement into the pores of the
second surface region of the open porous metal. The open porous
metal portion of the orthopaedic implant may also be formed of a
plurality of porous metal fragments aggregated together with the
cement portion of the orthopaedic implant. Additionally, the
orthopaedic implant may be pliable and thereby capable of being
molded to the shape of a void in a bone.
Inventors: |
Monaghan; Matthew E.; (Fort
Wayne, IN) ; Hoeman; Timothy A.; (Morris Plains,
NJ) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Monaghan; Matthew E.
Hoeman; Timothy A. |
Fort Wayne
Morris Plains |
IN
NJ |
US
US |
|
|
Assignee: |
Zimmer, Inc.
Warsaw
IN
|
Family ID: |
47628446 |
Appl. No.: |
13/736614 |
Filed: |
January 8, 2013 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61584463 |
Jan 9, 2012 |
|
|
|
Current U.S.
Class: |
623/23.55 |
Current CPC
Class: |
A61L 27/446 20130101;
A61F 2002/2892 20130101; A61F 2002/2825 20130101; A61L 27/04
20130101; A61F 2/2846 20130101; A61F 2/34 20130101; A61L 27/34
20130101; A61F 2002/2835 20130101; A61F 2/28 20130101; A61F 2/30767
20130101; A61L 27/427 20130101; A61L 27/56 20130101; A61L 2430/02
20130101; A61F 2002/2832 20130101; A61L 27/34 20130101; C08L 33/12
20130101 |
Class at
Publication: |
623/23.55 |
International
Class: |
A61F 2/30 20060101
A61F002/30 |
Claims
1. An orthopaedic implant for filling a bone void, comprising: an
open porous metal portion having a first porous layer and a second
porous layer; and a curable fixative at least partially disposed
over an area of said first porous layer, said curable fixative also
at least partially disposed within said first porous layer.
2. The orthopaedic implant of claim 1, wherein said first porous
layer comprises a plurality of first pores having a first nominal
pore diameter for contacting tissue, and said second porous layer
comprises a plurality of second pores having a second nominal pore
diameter.
3. The orthopaedic implant of claim 2, wherein said first porous
layer comprises a thickness of between one and ten first pore
diameters and said second porous layer comprises a thickness of
between one and ten second pore diameters.
4. The orthopaedic implant of claim 2, wherein said second nominal
pore diameter is greater than said first nominal pore diameter.
5. The orthopaedic implant of claim 1, wherein said open porous
metal portion comprises a flexible sheet having a thickness of no
more than twelve pore diameters.
6. An orthopaedic implant for filling a bone void, comprising: a
plurality of open porous metal fragments arranged in a layer having
first and second sides; a curable fixative at least partially
disposed over an area of said first side of said layer, said
curable fixative also at least partially disposed within said open
porous fragments; and a backing member contacting said second side
of said layer.
7. The orthopaedic implant of claim 6, wherein pores of said metal
fragments on said second side of said layer have a first nominal
pore diameter for contacting tissue, and said pores of said metal
fragments on said first side of said layer have a second nominal
pore diameter.
8. The orthopaedic implant of claim 7, wherein said second nominal
pore diameter is greater than said first nominal pore diameter.
9. The orthopaedic implant of claim 6, wherein said backing member
includes an adhesive surface contacting said second side of said
layer.
10. An orthopaedic implant for filling a bone void, comprising: a
first plurality of open porous metal fragments arranged in a first
layer having first and second sides; a second plurality of open
porous metal fragments arranged in a second layer having first and
second sides; and a curable fixative disposed between said first
side of said first layer and said first side of said second player,
said curable fixative also at least partially disposed within said
first and second plurality of open porous metal fragments.
11. The orthopaedic implant of claim 10, wherein pores on said
first side of said first layer and said second layer comprise a
first nominal pore diameter for contacting tissue, and pores on
said second side of said first layer and second layer comprise a
second nominal pore diameter.
12. The orthopaedic implant of claim 11, wherein said second
nominal pore diameter is greater than said first nominal pore
diameter.
13. The orthopaedic implant of claim 10, wherein pores on said
second side of said first layer comprise a first nominal pore
diameter and pores on said second side of said second layer
comprise a second nominal pore diameter, wherein said second
nominal pore diameter is greater than said first nominal pore
diameter.
14. The orthopaedic implant of claim 10 further comprising a
backing member contacting said second side of said first layer.
15. The orthopaedic implant of claim 14 further comprising a second
backing member contacting said second side of said second
layer.
16. The orthopaedic implant of claim 15, wherein said backing
member includes an adhesive surface contacting said second side of
said first layer and said second backing member includes an
adhesive surface contacting said second side of said second
layer.
17. The orthopaedic implant of claim 10, wherein said first layer
comprises a thickness of no more than twelve pore diameters and
said second layer comprises a thickness of no more than twelve pore
diameters.
18. The orthopaedic implant of claim 17, wherein said thickness of
said first layer is greater than said thickness of said second
layer.
19. The orthopaedic implant of claim 10, wherein said first
plurality of open porous metal fragments comprise a substantially
uniform size and a substantially uniform shape.
20. The orthopaedic implant of claim 19, wherein said second
plurality of open porous metal fragments also comprise a
substantially uniform size and a substantially uniform shape, said
size and shape of said first plurality of open porous metal
fragments being substantially the same as said size and shape of
said second plurality of open porous metal fragments.
Description
CLAIM OF PRIORITY
[0001] This application claims the benefit of priority under 35
U.S.C. .sctn.119(e) of Monaghan et al., U.S. Provisional Patent
Application Ser. No. 61/584,463, entitled "POROUS METAL IMPLANTS
WITH BONE CEMENT", filed on Jan. 9, 2012, which is herein
incorporated by reference in its entirety.
BACKGROUND
[0002] 1. Field of the Disclosure
[0003] The present invention relates to filling voids in bones.
More particularly, the present invention relates to orthopaedic
implants having a porous metal portion and bone cement portion for
filling voids in bones, and methods for using the same.
[0004] 2. Description of the Related Art
[0005] Bone voids may result for a number of reasons. For example,
joint injuries or disease may result in the formation of defects
and voids in a bone. Additionally, many orthopaedic surgical
procedures require drilling into bone, thereby creating bone voids.
Further, the locations at which bone voids occur, and the size of
bone voids, are patient specific. Thus, the use of standard
implants for filling bone voids may not be possible.
SUMMARY
[0006] The present disclosure provides a porous metal implant with
bone cement for filling voids in bones.
[0007] According to an embodiment of the present disclosure, an
orthopaedic implant for filing a bone void is provided. The
orthopaedic implant comprises an open porous metal portion having a
first porous layer opposite a second porous layer, and a curable
fixative portion at least partially disposed over an area of the
first porous layer. The curable fixative is also at least partially
disposed within a portion of the first porous layer.
[0008] According to another embodiment of the present disclosure,
the first porous layer further comprises a plurality of first pores
having a first nominal pore diameter for contacting tissue and the
second porous layer further comprises a plurality of second pores
having a second nominal pore diameter.
[0009] According to yet another embodiment of the present
disclosure, the first porous layer comprises a thickness of between
one and ten first pore diameters and the second porous layer
comprises a thickness of between one and ten second pore
diameters.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The above-mentioned and other features and advantages of
this disclosure, and the manner of attaining them, will become more
apparent and the disclosure itself will be better understood by
reference to the following description of embodiments of the
disclosure taken in conjunction with the accompanying drawings,
wherein:
[0011] FIG. 1 is an enlarged view of the structure of an open
porous metal according to the instant disclosure;
[0012] FIG. 2 is a cross-sectional view of the open porous metal of
FIG. 1 having bone cement applied at the first surface region and
being received within the plurality of pores of the open porous
metal to a depth of approximately one-half the thickness of the
open porous metal;
[0013] FIG. 3 is a perspective view of the open porous metal of
FIGS. 1 and 2 showing the application of bone cement to the first
surface region of the open porous metal;
[0014] FIG. 4a is a cross-sectional view of an embodiment of an
open porous metal having larger pore sizes proximate the first
surface region and smaller pore sizes proximate the second surface
region;
[0015] FIG. 4b is another cross-sectional view of an embodiment of
an open porous metal having larger pore sizes proximate the first
surface region and smaller pore sizes proximate the second surface
region with an affixation substrate separating the plurality of
pores proximate the first surface region from the plurality of
pores proximate the second surface region;
[0016] FIG. 5a is an enlarged perspective view of an embodiment of
an orthopaedic implant according to the instant disclosure having
an open porous metal encircling a formed portion of bone
cement;
[0017] FIG. 5b is an enlarged perspective view of another
embodiment of an orthopaedic implant according to the instant
disclosure having an open porous metal partially encircling a
formed portion of bone cement;
[0018] FIG. 6 is an enlarged view of an embodiment of an
orthopaedic implant according to the instant disclosure having a
plurality of open porous metal fragments with bone cement applied
to the first surface region;
[0019] FIG. 7a is a cross-sectional view of the orthopaedic implant
of FIG. 6 showing the application of bone cement to the first
surface region of the plurality of open porous metal fragments
positioned within a support form;
[0020] FIG. 7b is another cross-sectional view of another
embodiment of an orthopaedic implant according to the instant
disclosure, illustrating the application of bone cement to the
first surface region of a plurality of open porous metal fragments
positioned on an adhesive surface of a backing film;
[0021] FIG. 7c is an cross-sectional view of another embodiment of
an orthopaedic implant according to the instant disclosure,
illustrating a first and second plurality of open porous metal
fragments spaced apart by bone cement, each plurality of metal
fragments having a first surface region contacting bone cement and
a second surface region positioned on an adhesive surface of a
backing film;
[0022] FIG. 8a is a cross-sectional view illustrating an
orthopaedic implant according to the present disclosure implanted
within a void in a tibia;
[0023] FIG. 8b is an enlarged view of the orthopaedic implant
implanted within the void of FIG. 8a;
[0024] FIG. 9a is another cross-sectional view illustrating an
orthopaedic implant according to the present disclosure implanted
within a void in the femur;
[0025] FIG. 9b is a enlarged view of the orthopaedic implant
implanted within the void of FIG. 9a;
[0026] FIG. 10a is a cross-sectional view illustrating an
orthopaedic implant according to the present disclosure implanted
within a void in the acetabulum;
[0027] FIG. 10b is an enlarged view of the orthopaedic implant
implanted within the void of FIG. 10a; and
[0028] FIG. 11 is a perspective view showing implantation of the
orthopaedic implant of FIG. 5a into a void in a tibia.
[0029] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplifications set out
herein illustrate exemplary embodiments of the disclosure and such
exemplifications are not to be construed as limiting the scope of
the disclosure in any manner.
DETAILED DESCRIPTION
[0030] The present disclosure provides orthopaedic implants having
an open porous metal portion together with a curable fixative, such
as bone cement. Advantageously, the orthopaedic implants disclosed
herein may be sized and shaped by a medical professional at the
time of surgery in a custom manner, in order to accommodate patient
specific needs.
[0031] With reference to FIG. 1, an illustrative embodiment of open
porous metal 100 is depicted. As shown, open porous metal 100
includes a plurality of ligaments 102 defining a plurality of
highly interconnected, three-dimensional open spaces or pores 104
therebetween. Also, the pores 104 of open porous metal 100 may form
a matrix of continuous channels having no dead ends between
ligaments 102. Therefore, it is within the scope of orthopaedic
implant 200 that open porous metal 100 may include up to 75%-85% or
more void space therein. As such, open porous metal 100 may be a
lightweight, strong porous structure which is substantially uniform
and consistent in composition.
[0032] According to the instant disclosure, embodiments of open
porous metal 100 may have a porosity of as low as 55%, 65%, or 75%
or as high as 80%, 85%, or 90%. An example of such an open porous
metal 100, comprising a biocompatible metal, is produced using
Trabecular Metal.TM. Technology generally available from Zimmer,
Inc., of Warsaw, Ind. Trabecular Metal.TM. is a trademark of
Zimmer, Inc. Such an open porous metal 100 may be formed from a
reticulated vitreous carbon foam substrate which is infiltrated and
coated with a biocompatible metal, such as tantalum, by a chemical
vapor deposition ("CVD") process in the manner disclosed in detail
in U.S. Pat. No. 5,282,861, the disclosure of which is expressly
incorporated herein by reference. In addition to tantalum, other
metals such as niobium, or alloys of tantalum and niobium with one
another or with other metals may also be used. Further, other
biocompatible metals, such as titanium, a titanium alloy, cobalt
chromium, cobalt chromium molybdenum, tantalum, or a tantalum alloy
may also be used.
[0033] Additionally, embodiments of open porous metal 100 may
comprise a Ti-6Al-4V ELI alloy, such as Tivanium.RTM. Alloy which
is available from Zimmer, Inc., of Warsaw, Ind. Tivanium.RTM. is a
registered trademark of Zimmer, Inc. Open porous metal 100 may also
comprise a fiber metal pad or a sintered metal layer, such as a
CSTi.TM., Cancellous-Structured Titanium.TM. coating or layer, for
example. CSTi.TM. porous layers are manufactured by Zimmer, Inc.,
of Warsaw, Ind. CSTi.TM. is a trademark of Zimmer, Inc.
[0034] In other embodiments, open porous metal 100 may comprise an
open cell polyurethane foam substrate coated with Ti-6Al-4V alloy
using a low temperature arc vapor deposition process. Ti-6Al-4V
beads may then be sintered to the surface of the Ti-6Al-4V -coated
polyurethane foam substrate. Additionally, another embodiment of
open porous metal 100 may comprise a metal substrate combined with
a Ti-6AL-4V powder and a ceramic material, which is sintered under
heat and pressure. The ceramic particles may thereafter be removed
leaving voids, or pores, in the substrate. Open porous metal 100
may also comprise a Ti-6Al-4V powder which has been suspended in a
liquid and infiltrated and coated on the surface of a polyurethane
substrate. The Ti-6Al-4V coating may then be sintered to form a
porous metal structure mimicking the polyurethane foam substrate.
Further, another embodiment of open porous metal 100 may comprise a
porous metal substrate having particles, comprising altered
geometries, which are sintered to a plurality of outer layers of
the metal substrate.
[0035] Further, other embodiments of open porous metal 100 may
comprise a porous collagen scaffold core with calcium phosphate
embedded therein. Still other embodiments of open porous metal 100
may include a type 1 collagen core matrix with bone and blood
fragments embedded therein. In yet other embodiments, open porous
metal 100 may comprise a synthetic hydroxylapatite scaffold core
having an external negative charge and having various growth
factors (e.g., osteocytic and fibrocytic growth factors) embedded
therein. Still other embodiments of open porous metal 100 within
the scope of the present disclosure may include a resorbable
inorganic calcium phosphate scaffold core with human fibrin
embedded therein. Additionally, some embodiments of open porous
metal 100 may comprise a synthetic biocompatible calcium sulfate
scaffold core.
[0036] Open porous metal 100 may also be fabricated such that it
comprises a variety of densities. In particular, as discussed in
the above-incorporated U.S. Pat. No. 5,282,861, open porous metal
100 may be fabricated to virtually any desired density, porosity,
and pore size. Thus, open porous metal 100 can be matched with
surrounding natural tissue in order to provide an improved matrix
for tissue ingrowth and mineralization, thereby aiding in fixation
of open porous metal 100 to the surrounding natural tissue.
[0037] Additionally, according to the instant disclosure, open
porous metal 100 may be fabricated to comprise substantially
uniform porosity, density, and/or pore size throughout, or to
comprise at least one of pore size, porosity, and/or density being
varied. For example, according to embodiments of orthopaedic
implant 200 disclosed herein, open porous metal 100 may have a
different pore size and/or porosity at different regions or layers
of open porous metal 100. The ability to selectively tailor the
structural properties of open porous metal 100, enables tailoring
of open porous metal 100 for distributing stress loads throughout
the surrounding tissue and tissue ingrown within open porous metal
100.
[0038] With reference to FIG. 2, an illustrative embodiment of
orthopaedic implant 200 is depicted. As shown in FIG. 2,
orthopaedic implant 200 comprises open porous metal 100 and bone
cement 120. According to embodiments of orthopaedic implant 200
disclosed herein, open porous metal 100 may comprise a porous
metallic sheet, being relatively thin (e.g., having a thickness of
four to ten pore diameters) and may also be at least partially
flexible or pliable. Thus, open porous metal 100 may be shaped and
sized according to a particular application. For example, a surgeon
may shape, cut, bend, or trim open porous metal 100 to any desired
custom size and shape in order to meet a particular need. Shaping
and sizing of open porous metal 100 may occur prior to, or after
bone cement 120 is applied to open porous metal 100. As such,
orthopaedic implant 200 may be used to fill unique bone voids
having different shapes and sizes and occurring at various patient
specific locations.
[0039] With reference to FIGS. 4a and 4b, two embodiments of open
porous metal 100, both having regions comprising different pore
sizes and porosity, are shown. Referring specifically to FIG. 4a,
open porous metal 100a comprises first layer 101a, second layer
103a, first surface region 106a, intermediate region 107a, and
second surface region 108a. As illustrated, the nominal pore size
of open porous metal 100a is relatively greater in first layer 101a
and at first surface region 106a as compared to second layer 103a
and second surface region 108a. In some embodiments of open porous
metal 100a, the alteration in pore size and porosity may gradually
occur between first layer 101a and second layer 103a to form a
gradually increasing or decreasing pore size gradient. In other
embodiments of open porous metal 100a, the change in pore size and
porosity may be defined and localized at interface region 107a,
such as illustrated in FIG. 4a.
[0040] Embodiments of open porous metal 100a, such as illustrated
in FIG. 4a, may comprise a reticulated vitreous carbon (RVC)
substrate of a uniform pore size having a biocompatible metal, such
as tantalum, infiltrated and coated thereon such as described in
the above-incorporated U.S. Pat. No. 5,282,861. According to the
instant disclosure, in order to form a porous metal having varying
pore sizes, a greater amount of the biocompatible metal may be
infiltrated and coated on the carbon substrate in the second layer
than in the first layer, resulting in the second layer having
decreased pore size. This may be accomplished by masking a portion
of the carbon substrate during the infiltration and deposition
process, or, following an initial extent of infiltration and
deposition of the metal, by at least partially filling a
sacrificial material into the pores of one of the layers, followed
by carrying out further infiltration and deposition of the metal
into the pores of the other layer and then removing the sacrificial
material.
[0041] Another embodiment of open porous metal 100a may comprise
two or more different carbon substrates, each comprising different
pore size and porosity. The two or more carbon substrates may then
be diffusion bonded together, for example at interface region 107a,
using applied pressure at an elevated temperature for an
appreciable period of time. Further, the two or more carbon
substrates may be combined through an infiltration and deposition
welding process, in which the substrates, perhaps following an
initial extent of infiltration and deposition of the metal into the
substrates as separate components, are held against one another
followed by exposing the combined substrate to a further extent of
infiltration and deposition of the metal to concurrently coat and
thereby fuse the substrates together. In a further embodiment, the
substrates may be fused together by a resistance welding process
using localized heat generated through electric resistance.
[0042] FIG. 4b provides another illustrative embodiment of open
porous metal 100 having regions comprising different pore sizes and
porosity. As shown in FIG. 4b, open porous metal 100b comprises
first layer 101b, second layer 103b, first surface region 106b,
intermediate region 107b, and second surface region 108b.
Intermediate region 107b of open porous metal 100b comprises
affixation substrate 110 positioned between first layer 101b having
greater pore size and decreased porosity, and second layer 103b
having smaller pore size and greater porosity. As shown, first
layer 101b is affixed to first surface 112 or affixation substrate
110 and second layer 103b is affixed to second surface 114 of
affixation substrate 110. Similar to the above-described embodiment
of FIG. 4a, first layer 101b and second layer 103b may be diffusion
bonded to first surface 112 and second surface 114 of affixation
plate 110, respectively, using applied pressure at an elevated
temperature for an appreciable period of time. Further, first layer
101b and second layer 103b may also be affixed to first surface 112
and second surface 114 of affixation plate 110, respectively, by
the infiltration and deposition welding described above, or through
resistance welding using heat generated through electric
resistance.
[0043] With reference to FIG. 3, preparation of an illustrative
embodiment of orthopaedic implant 200 is shown. According to the
embodiment presented in FIG. 3, bone cement 120 is applied, using
applicator 122, to first surface region 106 of open porous metal
100. As intended herein, applicator 122 refers to manual devices,
such as knives, scrapers, brush, depressors, swabs, and the like.
It is also within the scope of the preparation of orthopaedic
implant 200 that applicator 122 may include an automated applicator
capable of mechanically applying and/or spreading bone cement 120
onto first porous surface 106 of plurality of fragments 150.
Further, bone cement 120 may be applied to orthopaedic implant 200
manually, for example by hand.
[0044] Also, as used herein, bone cement 120 refers to a curable
fixative capable of affixing implants to bone and/or replacing or
remodeling lost bone. For example, poly (methyl methacrylate)
("PMMA") is one compound capable of comprising bone cement 120.
Bone cement 120 may also include other moldable materials, such as
biodegradable polymers, for example, polyhydroxyalkanoate.
Additionally, bone cement 120 will typically be capable of bonding
to one of, or both of, bone or an implant. Further, bone cement
120, according to the instant disclosure, may comprise a powder
capable of being mixed with a liquid, or a liquid or gel which
hardens into a solid material.
[0045] Bone cement 120 is applied to orthopaedic implant 200 such
that it is received within pores 104 of first layer 101 proximal
first surface region 106. Typically, bone cement 120 will be
applied in a form in which bone cement 120 is not fully cured,
i.e., is relatively thick and viscous but not fully hardened. As
shown in the illustrative embodiment of orthopaedic implant 200 of
FIG. 2, bone cement 120 may be received within pores 104 of first
layer 101 up to a depth of approximately one half the depth (in
pore diameters) of open porous metal 100. In other embodiments of
orthopaedic implant 200, bone cement 120 may be received within
pores 104 of first layer 101 up to a depth of approximately 10 pore
diameters. In yet other embodiments of orthopaedic implant 200,
bone cement 120 may be received within pores 104 of first layer 101
up to a depth of approximately 4-6 pore diameters. It is also
within the scope of the instant disclosure that bone cement 120 be
received within pores 104 of first layer 101 at a depth of less
than four pore diameters. The receipt of bone cement 120 within
pores 104 of open porous metal 100 creates a strong, rigid fixation
of bone cement 120 to open porous metal 100 following curing of the
bone cement 120.
[0046] Also, as shown in FIG. 2, bone cement 120 is not applied to
second surface region 108 of orthopaedic implant 200. Further, bone
cement 120 applied to first surface region 106 is not received
within plurality of pores 104 of first layer 101 such that bone
cement 120 extends through open porous metal 100 to the plurality
of pores 104 of second layer 103 and second surface region 108.
[0047] As referenced above, second surface region 108 provides a
tissue contacting surface of orthopaedic implant 200 which allows
for tissue ingrowth and mineralization within the plurality of
pores 104 proximal second surface region 108. Although not
specifically illustrated in the embodiment of orthopaedic implant
200 shown in FIG. 2, it should be understood that orthopaedic
implant 200 may comprise open porous metal 100 having any of
density, porosity, and pore size at second surface region 108 which
differs from the density, porosity, and pore size at first surface
region 106 (e.g., as depicted in FIGS. 4a and 4b). As such, open
porous metal 100 may be fabricated such that first surface region
106 includes pores 104 of a relatively larger size in order to
facilitate receipt of bone cement 120, and second surface region
108 may include pores 104 of a relatively smaller size that are
more tailored to facilitate ingrowth and/or mineralization of
orthopedic implant 200 with a specific tissue.
[0048] Additionally, it is within the scope of orthopaedic implant
200 that open porous metal 100 may be impregnated with and/or
coated with biologically active agents. Suitable biologically
active agents include, for example, antibiotics to reduce the
potential for infection and to promote healing, and growth factors
to promote bone and/or soft tissue ingrowth into open porous metal
100 comprising a tissue contacting surface of orthopaedic implant
200. By way of example, second surface region 108 may be
impregnated with osteocytic growth factors for promoting bone
ingrowth within the plurality of pores 104 proximal second surface
region 108. In some embodiments, strontium may be combined with the
orthopedic implants disclosed herein as an active agent to promote
bone growth.
[0049] Referring to FIGS. 5a and 5b, additional illustrative
embodiments of orthopaedic implant 200 are shown. According to FIG.
5a, open porous metal 100 may be applied to, or pressed into, a
formed portion of bone cement 120, such that open porous metal 100
encircles (or in some instances encases) bone cement 120. FIG. 5b
presents an illustrative embodiment of orthopaedic implant 200''
having open porous metal 100 applied to another formed portion of
bone cement 120, such that open porous metal 100 partially
encircles the bone cement 120 portion. In both embodiments of
orthopaedic implant 200', 200'' presented in FIGS. 5a and 5b, open
porous metal 100 may comprise a relatively thin metallic, malleable
sheet. As shown, open porous metal 100 is pressed into bone cement
120 such that bone cement 120 is received within the plurality of
pores 104 approximately one-half the depth of the sheet of open
porous metal 100. As such, a surgeon may custom form bone cement
120 of orthopaedic implants 200', 200'' to meet patient specific
needs by shaping and sizing bone cement 120 and the sheet of open
porous metal 100 during the surgical procedure.
[0050] Additionally, as shown in FIGS. 5a and 5b, open porous metal
100 is applied to bone cement 120 such that first surface region
106 contacts bone cement 120 and bone cement 120 is received within
the plurality of pores 104 proximal first surface region 106
similar to the embodiments of orthopaedic implant 200 presented in
FIGS. 2 and 3. Also, bone cement 120 is not applied to second
surface region 108 of orthopaedic implants 200', 200'', and bone
cement 120 received within the plurality of pores 104 proximal
first surface region 106 does not extend through open porous metal
100 to the plurality of pores 104 proximal second surface region
108. In this manner, the pores 104 of second surface region 108,
which may be relatively smaller than the pores 104 of first surface
region 106 and tailored in size to facilitate tissue ingrowth, are
exposed to surrounding bone and/or soft tissue to facilitate tissue
ingrowth and anchoring of orthopaedic implants 200', 200''.
[0051] Referring to FIGS. 6, 7a, 7b, and 7c, illustrative
embodiments of orthopaedic implant 250 are shown. Embodiments of
orthopaedic implant 250 may include any of the characteristics and
features discussed in regard to orthopaedic implant 200. In
addition to the features discussed with regard to orthopaedic
implant 200, embodiments of orthopaedic implant 250, such as
illustrated in FIG. 6, comprise a plurality of fragments 150.
According to the instant disclosure, the plurality of fragments 150
comprise fragments of open porous metal 100, as disclosed herein,
and may be formed in various sizes and shapes. In general, however,
where orthopaedic implant 250 is relatively thin and sheet-like in
shape, the plurality of fragments 150 will together typically have
substantially the same depth. Additionally, according to an
embodiment of orthopaedic implant 250, the plurality of fragments
150 may comprise at least one of pore size, density, and porosity
which is either uniform or varies from first surface region 106 to
second surface region 108 (as shown in FIGS. 4a and 4b).
[0052] With reference to FIGS. 7a, 7b, and 7c, illustrative
embodiments of orthopaedic implants 250, 250', and 250'',
respectively, are depicted.
[0053] According to the instant disclosure, preparation of the
embodiments of orthopaedic implants 250, 250', and 250'' may
comprise a sheet of open porous metal 100 being placed within form
130 (FIG. 7a), or adhered to backing film 140 (FIGS. 7b and 7c),
and then shattered. For example, a sheet of open porous metal 100
may be frozen by exposure to liquid nitrogen prior to being placed
in form 130 (FIG. 7a) or prior to or after being adhered to backing
film 140 (FIGS. 7b and 7c). Once the frozen sheet of open porous
metal 100 is within form 130 (FIG. 7a) or adhered to backing film
140 (FIGS. 7b and 7c), a force may be applied to the sheet of open
porous metal 100, thereby causing the sheet of open porous metal
100 to break into a plurality of fragments 150.
[0054] Additionally, although not depicted, each of the plurality
of fragments 150 may be prepared individually, according to the
fabrication of open porous metal 100 discussed in the
above-incorporated U.S. Pat. No. 5,282,861. In such case, the
plurality of fragments 150 may be positioned within form 130 (FIG.
7a) or adhered to backing film 140 (FIGS. 7b and 7c) prior to
applying bone cement 120.
[0055] According to the illustrative embodiments of orthopaedic
implant 250 depicted in FIGS. 6, 7a, 7b, and 7c, bone cement 120 is
applied to first surface region 106 of the plurality of fragments
150 and is received within the plurality of pores 104 proximal
first surface region 106. Bone cement 120, however, is not applied
to second surface region 108 of the plurality of fragments 150
illustrated in FIGS. 6, 7a, 7b, and 7c. Also, bone cement 120
applied to first surface region 106 is not received within the
plurality of pores 104 proximal first surface region 106 such that
it extends through open porous metal 100 to the plurality of pores
104 proximal second surface region 108.
[0056] With reference to FIGS. 7a and 7b, an illustrative
embodiment of an applicator 122 is depicted. According to the
instant disclosure, applicator 122 may be used for applying bone
cement 120 to first surface region 106 of plurality of fragments
150. As intended herein, applicator 122 refers to manual devices,
such as knives, scrapers, brush, depressors, swabs, and the like.
It is also within the scope of the instant disclosure that
applicator 122 may include an automated applicator capable of
mechanically applying and/or spreading bone cement 120 onto first
surface region 106 of plurality of fragments 150. Further, bone
cement 120 may be applied to orthopaedic implant 250 manually, for
example, by hand.
[0057] Referring specifically to FIG. 7a, a plurality of fragments
150 of orthopaedic implant 250 are positioned within form 130. Also
illustrated, sides 134 of form 130 provide support which aides in
holding plurality of fragments 150 in position during the process
of applying bone cement 120 (shown being applied using applicator
122). Form 130 includes bottom 132 and sides 134, and may be
comprised of a transparent material, thereby aiding in monitoring
the application of bone cement 120. Additionally, according to the
instant disclosure, form 130 may comprise a disposable material
capable of being removed (e.g., peeled or torn away) from
orthopaedic implant 250 upon application of bone cement 120.
Removal of form 130 from plurality of fragments 150 thereby
provides an implantable orthopaedic implant similar to orthopaedic
implant 250 exemplified in FIG. 6.
[0058] With reference to FIG. 7b, an exemplary embodiment of
orthopaedic implant 250' is depicted. As shown, second surface
region 108 of each of a plurality of fragments 150 of orthopaedic
implant 250' are positioned in contact with adhesive surface 142 of
backing film 140. According to the instant disclosure, backing film
140 aides in holding the plurality of fragments 150 in position
during the process of applying bone cement 120 (shown being applied
using applicator 122) to first surface region 106. Following the
application of bone cement 120 to the plurality of fragments 150,
backing film 140 may be removed, thereby exposing the pores of the
surface region adjacent backing film 140 to provide an implantable
orthopaedic implant similar to orthopaedic implant 250 exemplified
in FIG. 6.
[0059] Referring to FIG. 7c, an exemplary embodiment of orthopaedic
implant 250'' is exemplified. According to the illustrative
embodiment orthopaedic implant 250'' presented in FIG. 7c,
orthopaedic implant 250'' includes a first and a second plurality
of fragments 150, 150'. As shown, second surface region 108 of the
first plurality of fragments 150 is positioned in contact with
adhesive surface 142 of backing film 140 and second porous surface
108' of the second plurality of fragments 150' is positioned in
contact with adhesive surface 142' of a second backing film 140'.
Bone cement 120 is then applied to first surface region 106 of both
the first and second plurality of fragments 150, 150''.
[0060] As shown in FIG. 7c, once bone cement 120 has been applied
to the first surface region 106, 106' of the first and second
plurality of fragments 150, 150', the first and second plurality of
fragments 150, 150' are contacted together such that bone cement
120 separates the first surface region 106, of the first plurality
of fragments 150, from the first surface region 106' of the second
plurality of fragments 150'. Prior to implanting orthopaedic
implant 250'', backing films 140, 140' are removed from the first
and second plurality of fragments 150, 150'. Upon removal of
backing films 140, 140', an implantable orthopaedic implant 250''
is provided having second surface region 108, of the first
plurality of fragments 150, and second surface region 108' wherein
the pores of the second plurality of fragments 150' are exposed. As
such, when implanted, orthopaedic implant 250'' may contact bone,
soft tissue, and/or a combination of both at the second surface
region 108, 108' of the first and second plurality of fragments
150, 150'.
[0061] With reference to FIGS. 7b and 7c, backing film 140
(including backing film 140') may comprise a flexible plastic film,
such as tape, a paper film, and/or a metal tape having at least one
adhesive surface. It is also within the scope of the orthopaedic
implants exemplified in FIG. 7b (250') and FIG. 7c (250'') that
backing film 140 may comprise a rigid material.
[0062] According to the instant disclosure, removal of backing film
140 from the plurality of fragments 150 may be accomplished by
peeling away backing film 140 from second surface region 108. For
example, exposed surface 144 of backing film 140 may have a tab
which can be used for peeling or tearing backing film 140 away from
the plurality of fragments 150. Further, removal of backing film
140 may require use of an instrument, such as a surgical pick, to
peel or pry backing film 140 away from the plurality of fragments
150.
[0063] Further, the illustrative embodiments of orthopaedic implant
250 (exemplified in FIGS. 6, 7a, 7b, and 7c), are capable of being
customized in shape, size, depth, and orientation for filling bone
voids of varying sizes and shapes. According to the instant
disclosure, the shape, size, depth, and orientation of orthopaedic
implant 250 may be customized immediately prior to implantation
into a bone void such as by cutting or trimming to shape, for
example, and may be further customized by a surgeon during the
actual implantation process. Also, the ability to customize
orthopaedic implants 250 allows orthopaedic implants 250 to be used
for filling voids at various locations of a bone, and also for
securing soft tissue to bone.
[0064] Still further, in the embodiments described above in which
the porous layer(s) are formed of a plurality of porous metal
fragments which are at least partially coated and infiltrated with
bone cement, the resulting orthopaedic implant 250 may have an
enhanced degree of pliability or flexibility, allowing orthopaedic
implant 250 to accommodate and fill bone voids of complex and/or
geometrically demanding shapes.
[0065] By way of example, one or more of the embodiments of
orthopaedic implant 250 disclosed herein may be used for filling a
void, in a bone, having an uneven surface and depth. According to
the instant disclosure, a surgeon may prepare orthopaedic implant
250 according to any of the preparations depicted in FIGS. 7a, 7b,
and 7c. Orthopaedic implant 250 may be implanted in the void such
that second porous surface of plurality of fragments contacts the
bone lining the void. During implantation into the void, the
medical professional may even further modify the shape, form, size,
and/or depth of orthopaedic implant 250 in order to fill the void
and replace the amount of, and contour of, the lost bone.
[0066] Having described various embodiments of orthopaedic implant
200 according to the instant disclosure, applications illustrating
and exemplifying uses of embodiments of orthopaedic implant 200 for
filling bone voids will now be described. As used in reference to
FIGS. 8-10, unless noted otherwise, reference to orthopaedic
implant 200 is intended to represent any and all embodiments of the
orthopaedic implants disclosed herein.
[0067] According to an embodiment of the instant disclosure,
illustrated in FIGS. 8a and 8b, orthopaedic implant 200 may be used
for filling a void V in a bone B (shown here as a proximal tibia).
FIG. 8a shows implantation of tibial tray 300 and augment 302 into
the intramedullary canal C of the bone B. As explained above, a
void V may occur or form in bone B for any of a number of various
reasons. As such, when tibial tray 300 and augment 302 are
implanted, orthopaedic implant 200 may be used to fill the void V
and reconstruct the natural contour of the intramedullary canal of
bone B such that augment 302 may more closely fit into the canal
C.
[0068] With reference to FIG. 8b, orthopaedic implant 200 is
orientated in the void V such that second surface region 108
contacts the bone B lining the void V. As described above, second
surface region 108 allows for ingrowth of bone into the plurality
of pores 104 proximal second surface region 108, thereby aiding the
initial fixation of orthopaedic implant 200 to the bone B.
[0069] FIG. 8b also illustrates bone cement 120 which is applied to
and received within the pores 104 of first surface region 106 of
orthopaedic implant 200 as described above. The bone cement 120
applied to the top of first surface region 106 may then be further
shaped (prior to or during implantation of orthopaedic implant 200)
to fill the remainder of the void V and reconstruct the contour of
the canal C of bone B.
[0070] Additionally, according to an embodiment of the instant
disclosure augment 302 may itself be formed of open porous metal as
disclosed herein. Thus, when augment 302 is implanted into canal C,
bone cement 120 applied to first surface region 106 of orthopaedic
implant 200 may also be at least partially received within the open
porous metal comprising augment 302, thereby aiding in the initial
fixation of augment 302.
[0071] Referring to FIGS. 9a and 9b, another illustration of an
embodiment of orthopaedic implant 200 being used to fill a void V
in a bone B (shown here as a proximal femur) is provided. As shown,
orthopaedic implant 200 is used to fill a void V in a bone B prior
to implantation of femoral stem 304 into the femoral canal C of
bone B.
[0072] With reference to FIG. 9b, orthopaedic implant 200 is
orientated in the void V such that second surface region 108
contacts the bone B outlining the void V. As described in detail
above, the plurality of pores 104 proximal to second surface region
108 allow for ingrowth of bone in the plurality of pores 104,
thereby aiding the initial fixation of orthopaedic implant 200 to
the bone B.
[0073] FIG. 9b also illustrates bone cement 120 which is applied to
and received within the plurality of pores 104 of first surface
region 106 of orthopaedic implant 200 as described above. The bone
cement 120 applied to the top of first surface region 106 may then
be further shaped (prior to or during implantation of orthopaedic
implant 200) to fill the remainder of void V and reconstructing the
contour of canal of bone B.
[0074] Additionally, according to an embodiment of the instant
disclosure at least a portion of femoral stem 304 may itself be
formed of open porous metal as disclosed herein. Thus, when femoral
stem 304 is implanted into the femoral canal C, bone cement 120
applied to first surface region 106 of orthopaedic implant 200 may
also be at least partially received within the open porous metal
comprising femoral stem 304, thereby aiding in initial fixation of
femoral stem 304.
[0075] Referring to FIGS. 10a and 10b, yet another illustration of
an embodiment of orthopaedic implant 200 being used to fill a void
V in a bone B (shown here as the acetabulum) is depicted. As shown,
orthopaedic implant 200 is used to fill a void V in a bone B prior
to affixation of acetabular cup 306 to the acetabulum.
[0076] With reference to FIG. 10b, orthopaedic implant 200 is
orientated in the void V such that second surface region 108
contacts the bone B outing the void V. As described in detail above
second surface region 108 allows for ingrowth of bone into the
plurality of pores 104 proximal second surface region 108, thereby
aiding the initial fixation of orthopaedic implant 200 to the bone
B.
[0077] Further, orthopaedic implant 200 may be utilized during an
orthopaedic implant revision procedure. With reference to FIGS. 10a
and 10b, orthopaedic implant 200 may be utilized during a hip
implant revision procedure for filling void V within the
acetabulum. As depicted in FIG. 10a, use of orthopaedic implant 200
for filling void V in the acetabulum during a revision procedure,
allows a surgeon to implant a revision acetabular cup 306 (of
identical size to the prior acetabular cup) without requiring
removal of additional bone stock from the surface of the
acetabulum.
[0078] As with FIGS. 8b and 9b, FIG. 10b also illustrates bone
cement 120 which is applied to and received within the plurality of
pores 104 of first surface region 106 of orthopaedic implant 200.
The bone cement 120 applied to the top of first surface region 16
may then be further shaped (prior to or during implantation of
orthopaedic implant 200) to fill the remainder of the void V and
reconstruct the contour of the missing acetabular bone B.
[0079] Additionally, according to an embodiment of the instant
disclosure at least a portion of the outer hemispherical surface of
acetabular cup 306 may itself be formed of open porous metal as
disclosed herein. Thus, when acetabular cup 306 is implanted within
the acetabulum, bone cement 120 applied to the first surface region
106 of orthopaedic implant 200 may be at least partially received
within the open porous metal comprising acetabular cup 306, thereby
aiding in the initial fixation of acetabular cup 306.
[0080] With reference to FIG. 11, an illustrative embodiment of
orthopaedic implant 200 (similar to orthopaedic implant 200'
disclosed in FIG. 5a) being used to fill a void V in a bone B
(shown here as a proximal tibia) is depicted. By way of example,
void V may have resulted following removal of a portion of the
proximal tibia during procurement of a portion of the patellar
tendon for use as a graft.
[0081] As shown, orthopaedic implant 200' is oriented in the void V
such that second surface region 108 contacts the bone B lining the
void V. As described above, second surface region 108 allows for
ingrowth of bone into the plurality of pores 104 proximal second
surface region 108, thereby aiding the initial fixation of
orthopaedic implant 200' to the bone B.
[0082] As with other embodiments of orthopaedic implant 200
described herein, bone cement 120 aides in shaping orthopaedic
implant 200' such that second surface region 108 contacts the bone
B lining the void V. Bone cement 120 further aides in replacing and
reconstructing the contour of the missing bone B.
[0083] While this disclosure has been described as having exemplary
designs, the present disclosure can be further modified within the
spirit and scope of this disclosure. This application is therefore
intended to cover any variations, uses, or adaptations of the
disclosure using its general principles. Further, this application
is intended to cover such departures from the present disclosure as
come within known or customary practice in the art to which this
disclosure pertains and which fall within the limits of the
appended claims.
* * * * *