U.S. patent application number 14/204693 was filed with the patent office on 2014-09-18 for fixation of bone implants.
This patent application is currently assigned to SMED-TA/TD, LLC. The applicant listed for this patent is SMed-TA/TD, LLC. Invention is credited to Travis J. Geels, Troy D. Knapp, Gregory C. Stalcup.
Application Number | 20140277530 14/204693 |
Document ID | / |
Family ID | 51531347 |
Filed Date | 2014-09-18 |
United States Patent
Application |
20140277530 |
Kind Code |
A1 |
Stalcup; Gregory C. ; et
al. |
September 18, 2014 |
FIXATION OF BONE IMPLANTS
Abstract
The present invention provides an orthopaedic implant including
an articulating tray, a support tray connected to the articulating
tray and a bone ingrowth layer connected to the support tray. The
articulating tray has an articulating surface and an interface
surface opposed to the articulating surface. The support tray has a
first connecting surface that is connected to the interface surface
and a second connecting surface that is opposed to the first
connecting surface and connected to the bone ingrowth layer. Also
provided is an orthopaedic implant with an articulating component
and a body component connected to the articulating component. The
articulating component has an articulating surface and an interface
surface opposed to the articulating surface. The body component has
a first surface connected to the interface surface, a second
surface opposed to the first surface and at least one protrusion
that extends away from the second surface.
Inventors: |
Stalcup; Gregory C.;
(Columbia City, IN) ; Knapp; Troy D.; (Alachua,
FL) ; Geels; Travis J.; (Fort Wayne, IN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
SMed-TA/TD, LLC |
Columbia City |
IN |
US |
|
|
Assignee: |
SMED-TA/TD, LLC
Columbia City
IN
|
Family ID: |
51531347 |
Appl. No.: |
14/204693 |
Filed: |
March 11, 2014 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61789158 |
Mar 15, 2013 |
|
|
|
Current U.S.
Class: |
623/20.17 ;
623/20.14 |
Current CPC
Class: |
A61B 17/8605 20130101;
A61B 17/864 20130101; A61F 2/389 20130101; A61F 2002/30578
20130101; A61B 2017/0404 20130101; A61F 2002/30878 20130101; A61B
17/844 20130101; A61F 2002/3895 20130101; A61B 17/8685 20130101;
A61F 2002/30594 20130101; A61B 17/0401 20130101; A61B 17/8635
20130101; A61F 2002/2817 20130101; A61F 2002/30484 20130101; A61B
17/842 20130101; A61F 2/30 20130101; A61F 2002/30886 20130101; A61B
2017/0414 20130101; A61B 2017/8655 20130101; A61F 2002/3068
20130101; A61F 2/30749 20130101; A61F 2002/3092 20130101; A61B
17/1764 20130101; A61F 2/3859 20130101 |
Class at
Publication: |
623/20.17 ;
623/20.14 |
International
Class: |
A61F 2/30 20060101
A61F002/30 |
Claims
1. An orthopaedic implant, comprising: an articulating tray having
an articulating surface and an interface surface opposed to said
articulating surface; a support tray connected to said interface
surface and having a first connecting surface and a second
connecting surface opposed to said first connecting surface, said
first connecting surface being connected to said interface surface;
and a bone ingrowth layer connected to said second connecting
surface.
2. The orthopaedic implant according to claim 1, wherein said bone
ingrowth layer includes a plurality of pores formed throughout that
are configured to encourage bone ingrowth into said bone ingrowth
layer.
3. The orthopaedic implant according to claim 2, wherein said bone
ingrowth layer has at least one biologically active substance
residing within at least one of said plurality of pores.
4. The orthopaedic implant according to claim 3, wherein said
support layer has a reservoir formed therein configured to hold at
least one therapeutic agent and a plurality of openings formed
through said second connecting surface, said plurality of openings
fluidly connecting said reservoir to said bone ingrowth layer.
5. The orthopaedic implant according to claim 4, wherein said
support layer has an exposed surface with a port formed through
said exposed surface to said reservoir.
6. The orthopaedic implant according to claim 2, wherein said
orthopaedic implant is configured as one of a femoral implant and a
tibial implant.
7. The orthopaedic implant according to claim 5, wherein said
support layer is separably connected to at least one of said
interface surface and said bone ingrowth layer.
8. The orthopaedic implant according to claim 5, further comprising
a polymer retention layer connecting said interface surface to said
first connecting surface.
9. An orthopaedic implant, comprising: an articulating component
having an articulating surface and an interface surface opposed to
said articulating surface; and a body component connected to said
interface surface and having a first surface, a second surface
opposed to said first surface and at least one protrusion, said
first surface connected to said interface surface and said at least
one protrusion extending away from said second surface and
configured to be biased toward an anatomy structure by a tensile
force.
10. The orthopaedic implant according to claim 9, wherein said body
component includes a support component connected to said
articulating component and a bone fixation component connected to
said support component.
11. The orthopaedic implant according to claim 10, wherein said at
least one protrusion is angled relative to said second surface.
12. The orthopaedic implant according to claim 10, wherein said at
least one protrusion is an integral part of at least one of said
support component and said bone fixation component.
13. The orthopaedic implant according to claim 10, further
comprising a tensioning member connected to said at least one
protrusion.
14. The orthopaedic implant according to claim 13, wherein said
tensioning member includes an anchor and a tension transmitter
connecting said anchor to said at least one protrusion.
15. The orthopaedic implant according to claim 10, wherein said at
least one protrusion has a bore with an entrance formed
therethrough.
16. The orthopaedic implant according to claim 15, wherein said at
least one protrusion has a locking feature formed one of inside and
outside said bore adjacent to said entrance.
17. The orthopaedic implant according to claim 16, further
comprising a tensioning member connected to said locking
feature.
18. The orthopaedic implant according to claim 13, further
comprising a bone adhesive connected to said second surface.
19. A method of implanting an orthopaedic implant, comprising the
steps of: providing an orthopaedic implant including an
articulating component having an articulating surface and an
interface surface opposed to said articulating surface and a body
component connected to said interface surface having a first
surface, a second surface opposed to said first surface and at
least one protrusion, said first surface being connected to said
interface surface and said at least one protrusion extending away
from said second surface; preparing an anatomical site for
implantation; placing said orthopaedic implant at the prepared
anatomical site; and providing a tensile force to said at least one
protrusion to force said orthopaedic implant into said prepared
anatomical site.
20. The method according to claim 19, wherein said preparing step
includes resectioning said anatomical site and creating at least
one bore through said anatomical site that provides access to said
protrusion when said orthopaedic implant is placed within said
prepared anatomical site.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This is a non-provisional application based upon U.S.
provisional patent application Ser. No. 61/789,158, entitled
"FIXATION OF BONE IMPLANTS", filed Mar. 15, 2013, which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to orthopaedic implants, and,
more particularly, to knee implants.
[0004] 2. Description of the Related Art
[0005] The knee is a common site of orthopaedic problems in
patients that require surgery. The cartilage in the knee is
especially vulnerable to injury throughout a patient's lifetime and
generally does not repair itself like other tissues in the body.
When the cartilage in a knee is damaged or destroyed, the femur and
tibia, which are normally separated and lubricated by the
cartilage, can rub together, which causes various problems.
[0006] If surgical intervention to repair the cartilage of the knee
is insufficient, a knee implant is usually implanted into the
patient on a prepared surface of either the femur or tibia. Knee
implants typically have an articulating surface that simulates the
body's natural cartilage, allowing the femur and tibia to stay
connected and glide relative to each other as they would if healthy
cartilage was present.
[0007] When installing the knee implant, an adhesive is often used
to affix the implant to either the femur or tibia and allow for
proper fixation of the implant. Bone cement is a popular adhesive
choice because it forms a good interface with the bone and has good
biocompatibility. There are several advantages that could be gained
from reducing the use of bone cement to fixate a knee implant to
the prepared bone surface. Bone cement has a putty-like consistency
and is prone to spreading during surgery. When the surgeon presses
the knee implant on to the bone cement on the prepared bone
surface, there is a risk of bone cement squeezing out from between
the knee implant and the prepared bone surface if an excessive
amount of bone cement or pressing force is applied. This loose bone
cement is usually removed during surgery, which prolongs the
surgery.
[0008] What is needed in the art is a way of fixating knee implants
to a femur or tibia that reduces or eliminates the need to use bone
cement.
SUMMARY OF THE INVENTION
[0009] The present invention provides knee implants that take
advantage of natural bone ingrowth or tensile forces to reduce or
eliminate the need for bone cement.
[0010] The invention in one form is directed to an orthopaedic
implant that includes an articulating tray, a support tray
connected to the articulating tray, and a bone ingrowth layer
connected to the support tray. The articulating tray has an
articulating surface and an interface surface that is opposed to
the articulating surface. The support tray has a first connecting
surface connected to the interface surface and a second connecting
surface connected to the bone ingrowth layer.
[0011] The invention in another form is directed to an orthopaedic
implant that includes an articulating component and a body
component connected to the articulating component. The articulating
component has an articulating surface and an interface surface that
is opposed to the articulating surface. The body component has a
first surface connected to the interface surface, a second surface
opposed to the first surface, and at least one protrusion. The
protrusion extends away from the second surface and is configured
to be biased toward an anatomy structure by a tensile force.
[0012] The invention in yet another form is directed to a method of
implanting an orthopaedic implant that includes an articulating
component with an articulating surface and an interface surface
opposed to the articulating surface, and a body component with a
first surface connected to the interface surface, a second surface
opposed to the first surface and at least one protrusion that
extends away from the second surface. An anatomical site is
prepared for implantation and the orthopaedic implant is placed at
the prepared anatomical site. A tensile force is provided to the
protrusion to force the orthopaedic implant into the prepared
anatomical site.
[0013] An advantage of the present invention is that it reduces or
eliminates the need to use bone cement during surgery which can
save time during surgery and reduce the risk of a patient requiring
a revision surgery in the future.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The above-mentioned and other features and advantages of
this invention, and the manner of attaining them, will become more
apparent and the invention will be better understood by reference
to the following description of embodiments of the invention taken
in conjunction with the accompanying drawings, wherein:
[0015] FIG. 1 is a perspective view of an embodiment of an
orthopaedic implant according to the present invention;
[0016] FIG. 2 is a partially exploded view of another embodiment of
an orthopaedic implant according to the present invention;
[0017] FIG. 3 is a cross-sectional view of a tibia with an
orthopaedic implant fixated according to the present invention;
[0018] FIG. 4 is a cross-sectional view of a bone screw according
to the present invention;
[0019] FIG. 5 is a cross-sectional partially exploded view of a
tibia with an orthopaedic implant fixated according to the present
invention;
[0020] FIG. 6 is an exploded view of a jig being used to prepare a
tibia according to the present invention;
[0021] FIG. 7 is an exploded view of a tibia with another
embodiment of an orthopaedic implant fixated according to the
present invention;
[0022] FIG. 8 is a cross-sectional view of the tibia with the
orthopaedic device fixated shown in FIG. 7;
[0023] FIG. 9 is another perspective view of the tibia with the
orthopaedic device fixated shown in FIG. 7;
[0024] FIG. 10 is an exploded view of a tibia with yet another
embodiment of an orthopaedic implant fixated according to the
present invention;
[0025] FIG. 11 is a cross-sectional view of a tibia with yet
another embodiment of an orthopaedic implant fixated according to
the present invention;
[0026] FIG. 12 is a cross-sectional view of the embodiment of the
present invention shown in FIG. 11 having perpendicular protrusions
rather than angled protrusions;
[0027] FIG. 13 is a perspective view of an embodiment of yet
another orthopaedic implant according to the present invention;
[0028] FIG. 14 is another perspective view of the embodiment of the
present invention shown in FIG. 13;
[0029] FIG. 15 is a perspective view of a tibia with yet another
embodiment of an orthopaedic implant fixated according to the
present invention;
[0030] FIG. 16 is a cross-sectional view of the embodiment of the
present invention shown in FIG. 15;
[0031] FIG. 17 is an exploded view of a femur with an orthopaedic
implant fixated according to the present invention;
[0032] FIG. 18 is a cross-sectional view of the embodiment of the
present invention shown in FIG. 17;
[0033] FIG. 19 is yet another embodiment of an orthopaedic implant
according to the present invention;
[0034] FIG. 20 is a cross-sectional view of a femur with the
orthopaedic implant shown in FIG. 19 fixated according to the
present invention;
[0035] FIG. 21 is yet another embodiment of an orthopaedic implant
according to the present invention;
[0036] FIG. 22 is a cross-sectional view of a femur with the
orthopaedic implant shown in FIG. 21 fixated according to the
present invention;
[0037] FIG. 23 is an exploded view of a support body and bone
ingrowth layer according to the present invention;
[0038] FIG. 24 is a partially exploded view of yet another
embodiment of an orthopaedic implant incorporating the support body
and bone ingrowth layer shown in FIG. 23 according to the present
invention;
[0039] FIG. 25 is a perspective view of yet another embodiment of
an orthopaedic implant incorporating the support body and bone
ingrowth layer shown in FIG. 23 according to the present
invention;
[0040] FIG. 26 is a perspective view of a tibia with the
orthopaedic implant shown in FIG. 25 fixated according to the
present invention;
[0041] FIG. 27 is a perspective view of a tibia with yet another
embodiment of an orthopaedic implant fixated according to the
present invention; and
[0042] FIG. 28 is a perspective view of a tibia with yet another
embodiment of an orthopaedic implant fixated according to the
present invention.
[0043] Corresponding reference characters indicate corresponding
parts throughout the several views. The exemplifications set out
herein illustrate embodiments of the invention and such
exemplifications are not to be construed as limiting the scope of
the invention in any manner.
DETAILED DESCRIPTION OF THE INVENTION
[0044] Referring now to the drawings, and more particularly to
FIGS. 1 and 2, there is shown an orthopaedic implant 30 which
generally includes an articulating tray 32, a support tray 34
connected to the articulating tray 32, and a bone ingrowth layer 36
connected to the support tray 34. The articulating tray 32 has an
articulating surface 38 that is shaped to be contacted by either a
femur or tibia when the implant 30 is placed within a patient. The
articulating surface 38 can be shaped to have a concave portion 40
where a head of a femur or tibia will make contact with the
articulating surface 38 during implantation. The concave portion 40
allows the head to glide smoothly across the articulating surface
38 during movement of the femur and tibia. An interface surface 42
(shown in FIG. 2) is a surface of the articulating tray 32 that is
opposite the articulating surface 38. The interface surface 42 can
be a flat surface or can have features (not shown) formed on the
surface 42 that allow the articulating tray 32 to removably connect
to the support tray 34. FIG. 1 shows the articulating tray 32 being
irreversibly attached to the support tray 34 while FIG. 2 shows the
articulating tray 32 being reversibly attachable to the support
tray 34. If the articulating tray 32 is irreversibly attached to
the support tray 34, a polymer retention layer 44 can be attached
to the interface surface 42 and support tray 34 to promote a better
attachment of the articulating tray 32 to the support tray 34. The
articulating tray 32 can be made from any material suitable for
providing an articulating surface 38 that simulates a patient's
natural cartilage. A widely used material for such an application
is ultra-high molecular weight polyethylene (UHMW-PE), but other
biocompatible polymers and metals could also be used.
[0045] A support tray 34 is connected to the interface surface 42
of the articulating tray 32 and has a first connecting surface 46
that connects to the interface surface, and a second connecting
surface (not seen) that is opposed to the first connecting surface
46. The support tray 34 is configured to be a complementary shape
to the articulating tray 32 to provide good attachment between the
two components. The support tray 34 provides additional rigidity
and support to the articulating tray 32, which is typically thinner
and made of lower strength material(s) than the support tray 34. As
previously described, the first connecting surface 46 can either
attach directly to the interface surface 42, or be attached to the
polymer retention layer 44 which will connect the first connecting
surface 46 to the interface surface 42, especially in the case that
irreversible attachment is desired. As shown in FIG. 2, the first
connecting surface 46 can be formed as a recess within the support
tray 34 to allow the articulating tray 32 to snap in to the recess
and attach to the support tray 34. The support tray 34 lends
strength to the articulating tray 32, and can be made of any
appropriate material(s) for this purpose including titanium,
stainless steel, cobalt chrome, hardened polymers and ceramics.
[0046] A bone ingrowth layer 36 is connected to the second
connecting surface of the support tray 34. The bone ingrowth layer
36 can be shaped to entirely cover the second connecting surface of
the support tray 34 or only a portion of the surface. The bone
ingrowth layer 36 allows for bone to grow into the layer 36,
providing fixation for the implant 30 on the femur or tibia. The
bone ingrowth layer 36 is shaped to be complementary to a prepared
section of the femur or tibia where the implant 30 will be fixated.
The bone ingrowth layer is porous and can have a roughened outer
surface 48, which will provide immediate fixation to the prepared
section through frictional forces caused by the abrasiveness of the
roughened outer surface 48. Pores 50 can be formed throughout the
bone ingrowth layer 36 to allow for bone tissue ingrowth into the
layer 36. The pores 50 should be sized, shaped and distributed
throughout the layer 36 to allow for the desired amount of bone
tissue ingrowth, which will provide the fixation necessary for the
implant 30 to stay attached to the femur or tibia in the absence of
bone cement or other attachment features. The pores 50 can also
have biologically active substances, such as growth factors, placed
within to encourage bone tissue growth into the pores 50. Other
biologically active substances that can be included in the pores 50
include anti-inflammatories, antibiotics, painkillers,
anti-rejection drugs and other medically useful substances. The
bone ingrowth layer 36 can be formed from a variety of materials.
Materials that have been found to be particularly useful for
forming the bone ingrowth layer 36 include titanium, cobalt-chrome,
stainless steel, polyether ether ketone (PEEK) and
hydroxyapatite.
[0047] Referring now to FIG. 3, a cross-sectional view of the
implant 30 previously described is shown implanted in a tibia 52.
Protrusions 54, 56 are formed in the implant 30 and rest inside
bores 58, 60 formed in the tibia 52. Although the implant 30 is
shown with the bone ingrowth layer 36 attached, it is also
contemplated that the bone ingrowth layer 36 can be removed if the
implant 30 has the protrusions 54, 56 included. The protrusions 54,
56 are angled relative to the support tray 34 and can provide some
fixation for the implant 30 while resting inside the bores 58, 60
before bone tissue ingrowth has begun in the bone ingrowth layer
36. While protrusion 56 is shown as solid, protrusion 54 has a bore
62 formed within and a pair of lips 64, 66 formed near an entrance
68 of the bore 62. The bore 62 allows for a tensioning member 70,
shown as a compression screw, to be inserted and provide a tensile
force to the protrusion 54 that will bias the implant 30 toward the
tibia 52. Mating features 72 on the screw 70 lock in with the lips
64, 66 to keep the screw 70 locked to the protrusion 54. Once the
screw 70 is locked to the protrusion 54, the screw 70 can be
advanced away from the implant 30, which provides the tensile force
to the protrusion 54 that biases the implant 30 toward the tibia
52. The protrusions 54 and 56 can be formed as an integral part of
the implant 30 or as an attachment to the implant 30. The
protrusion 54 can be formed of any materials capable of
withstanding the tensile force provided to the protrusion 54, which
will be similar to the materials used to create the support layer
34.
[0048] FIG. 4 shows a cross-sectional view of the screw 70 shown in
FIG. 3. The screw has a main body 74 with outer threads 76 formed
thereon and the mating features 72 at one end of the main body 74
and a torqueing end 78 at the other end of the main body 74. The
torqueing end 78 can interact with a corresponding torqueing device
to advance the screw 70 into or out of the bore 62. The screw 70
has an inner chamber 80 formed within which has an inner threading
82 that mates with an internal screw 84 within the inner chamber
80. As can be seen, the internal screw 84 has an elongated support
portion 86 connected to a main body 88 with a bore 90 formed within
to interact with a torqueing device and threads 92 formed on the
surface to interact with the inner threading 82. When the screw 70
has the internal screw 84 fully advanced within, the elongated
support portion 86 is held within a separation gap 94 between the
mating features 72, preventing collapse of the mating features 72
and maintaining the separation gap 94.
[0049] Referring now to FIG. 5, the implant 30 with screw 70
inserted is shown without the internal screw 84 advanced within the
inner chamber 80. Without the internal screw 84, there is nothing
to keep the mating features 72 separated so they can freely move
toward each other. This allows the screw 70 to be advanced toward
the bore 62 of the protrusion 54 until the mating features 72 are
pushed into the bore 62. Tapering of the mating features 72 allows
the lips 64, 66 to push the mating features 72 toward each other as
the screw 70 is advanced into the bore 62 and the mating features
72 to snap out when the tapering advances beyond the lips 64, 66,
providing an abutment of the mating features 72 to the lips 64, 66.
This abutment allows for tension to be transmitted to the
protrusion 54 as the screw 70 is advanced away from the implant 30.
Once the abutment is formed, the internal screw 84 is advanced so
that the elongated support portion 86 occupies the separation gap
94 between the mating features 72, preventing their collapse as the
screw 70 is advanced away from the implant 30. If so desired, the
internal screw 84 can be removed from the screw 70 so that the
screw 70 can be taken out of the bore 62.
[0050] Referring now to FIG. 6, a jig 96 is shown that can be used
to form bores 58 and 60 seen in FIG. 3 into the tibia. The jig 96
has multiple anchoring openings 98 through which pins 100 can be
inserted to attach the jig 96 to a prepared surface 102 of the
tibia. The jig 96 has drill openings 104 that are angled and
positioned to correspond to where the protrusions 54 and 56 will be
when the implant 30 is placed in the prepared surface 102. Once the
jig 96 is placed, bores 58 and 60 can be formed by advancing a
drill (not shown) through the drill openings 104.
[0051] Referring now to FIGS. 7, 8 and 9, an orthopaedic implant
110 is shown that includes a main body 112, a first protrusion 114,
an elongated protrusion 116 and a second protrusion (not shown).
The main body 112 can be similar to the previously described
implant 30, shown here without the bone ingrowth layer 36 attached.
The first protrusion 114 and the second protrusion can be
structured similarly to the protrusion 54 previously described and
shown, to interact with a screw 118 and internal screw 120 that are
structured similarly to the screw 72 and internal screw 84
previously described and shown. The elongated protrusion 116 fits
into a bore formed in a tibia 122 to help balance the tension that
is applied to the first protrusion 114 and second protrusion. As
shown in FIG. 9, when the implant 110 is fully installed, there
will be a pair of screws 118 holding the implant 110 tensioned to
the tibia 122. It is also contemplated that an implant could be
fixated to the tibia 122 using only one protrusion 114 and screw
118.
[0052] FIG. 10 shows an orthopaedic implant 130 that is similar to
the orthopaedic implant 110 previously described, but lacking the
elongated protrusion 116. The implant 130 has a pair of protrusions
132, 134 that can receive a tensile force from screws 136, 138. The
screws 136, 138 can be structured similarly to previously described
screws 70 and 118 with internal screws 84 and 120.
[0053] Referring now to FIGS. 11 and 12, an orthopaedic implant 140
is shown that includes an articulating tray 142, a support tray 144
connected to the articulating tray 142, and a bone ingrowth layer
146 connected to the support tray 144. The implant 140 can be
configured in similar fashion to the implant 30 described and shown
previously. The implant 140 also has a protrusion 148 formed as
part of the support tray 144 and a protrusion 150 formed as part of
the bone ingrowth layer 146. The protrusions 148 and 150 can be
angled relative to a bottom surface 152 of the articulating tray
142, as shown in FIG. 11, or be perpendicular to the bottom surface
of articulating tray 142, as shown in FIG. 12. The protrusion 148
has an opening 154 formed through that allows the protrusion 148 to
connect to a tensioning member 156. The tensioning member 156
includes an anchor 158, shown as a button with a larger diameter
than protrusion 148, and a tension transmitter 160, shown as a
suture. The button 158 has multiple openings 162 for the suture 160
to pass through. To fixate the implant 140, a pair of bores 164,
166 that closely match the size of protrusions 148 and 150 are
formed in a tibia 168 and protrusions 148 and 150 are placed in the
bores 164, 166. The suture 160 is then passed through one of the
openings 162 on the button 158, advanced through the bore 164 where
protrusion 148 rests, passed through the opening 154 on protrusion
148, advanced out of the bore 164 and passed through another
opening 162 on the button 158 to form a loop of suture. This
process can be repeated as many times as desired to produce one or
more loops of suture. When the desired number of loops are formed,
the suture 160 can be pulled to provide a tensile force to the
protrusion 148, forcing the implant 140 into the tibia 168, and
then tied to maintain the tensile force on the protrusion 148. The
tensile force from the suture 160 tied to the protrusion 148 helps
fixate the implant 140 to the tibia 168 while bone tissue grows
into the bone ingrowth layer 146. If desired, bone cement could be
used rather than the bone ingrowth layer 146 to help fixate the
implant 140 to the tibia 166. The tensioning member 156 could also
be changed to accommodate different surgical techniques.
[0054] Referring now to FIGS. 13 and 14, an orthopaedic implant 170
is shown that includes an articulating tray 172, a support tray 174
connected to the articulating tray 172, and a bone ingrowth layer
176 connected to the support tray 174. The articulating tray 172
and support tray 174 of implant 170 can be configured similarly to
the previously described articulating tray 32 and support tray 34
of orthopaedic implant 30. The bone ingrowth layer 176 includes
multiple protrusions 178 integrally formed in the bone ingrowth
layer 178. These protrusions 178 can be shaped as cylindrical pegs
to fit in bores formed on a tibia. A fixation plate 180 is
connected to the support tray 174 and includes multiple openings
182. The openings 182 are sized to have screws passed through, that
will help fixate the implant 170 to the tibia during implantation.
The implant 170 will typically be an onset unit, where the tibia is
prepared by creating a flat surface on the tibia where the implant
170 rests.
[0055] FIGS. 15 and 16 show an orthopaedic implant 190 similar to
the orthopaedic implant 140 previously described, but having an
articulating tray 192, support tray 194 and bone ingrowth layer 196
that are shaped to make the implant 190 an inset implant that rests
within a tibia 198. The articulating tray 192 has a pair of tapered
surfaces 200 that conform to a surface 202 of the tibia 198,
allowing for as much of the tibia 198 to be preserved as possible
while still attaining a good fixation of the implant 190. The
support tray 194 has a protrusion 204 with an opening 206 and the
bone ingrowth layer 196 has a protrusion 208 similar to previously
described orthopaedic implant 140. The tensioning member 156 could
be used to apply tension to protrusion 204, as previously
described. Fixating the implant 190 would be accomplished in a
similar fashion to the way orthopaedic implant 140 is fixated.
[0056] While the previously described implants and fixation
techniques have all been described for use in a patient's tibia,
similar implants and techniques can be used for implant fixation in
a patient's femur.
[0057] As shown in FIGS. 17 and 18, an orthopaedic implant 210 can
be fixated in a patient's femur 212 in a similar fashion to the
previously described implants for a patient's tibia. The implant
210 has a curved articulating tray 214 and a curved body tray 216
connected to the articulating tray 214. The articulating tray 214
and body tray 216 are curved to conform to the anatomical shape of
the femur 212. The body tray 216 has a pair of protrusions 218
integrally formed that are placed in a pair of bores 220 formed in
the femur 212. The protrusions 218 can be structured any way
previously described for use in a tibia. A pair of screws 222,
similar to previously described screws with internal screws, are
inserted into the protrusions 218 and, once they are locked into
the protrusions 218, advanced out of the bores 220 to provide a
tensile force fixating the implant 210 to the femur 212. While
implant 210 is not shown with a bone ingrowth layer attached to the
body tray 216, such a layer could be attached to the body tray 216
to provide extra fixation to the implant 210.
[0058] Referring now to FIGS. 19 and 20, an orthopaedic implant 230
is shown that can be fixated in a patient's femur 232. The
orthopaedic implant 230 includes a curved body tray 234 with an
articulating surface 236 and a bone ingrowth layer 238 attached to
the body tray 234 at a surface opposite the articulating surface
236. The body tray 234 and articulating surface 236 can be
structured as previously described. A pair of pegs 240 are bonded
to the bone ingrowth layer 238 and configured similarly to
previously described protrusion 54. The pegs 240 each have a bore
242 with an entrance 244 formed within and lips 246 near the
entrance 244. The lips 246 allow screws 248, similar to previously
described screws with internal screws, to lock into the pegs 240
and apply a tensile force to the pegs 240, similar to previously
described screws. The pegs 240 can be made of titanium and bonded
to the implant 230 by any means that allow for a secure bond.
[0059] Referring now to FIGS. 21 and 22, an orthopaedic implant 250
is shown that includes a body tray 252 with an attached bone
ingrowth layer 254. The bone ingrowth layer 254 is bonded to a pair
of split pegs 256. The split pegs 256 each have an end 258 bonded
to the bone ingrowth layer 254 and a pair of outside lips 260 at an
opposite end 262. The outside lips 260 are tapered so that they
have a lowest diameter d1 at end 262 that increases to a max
diameter d2 in the direction of end 258. A split 264 in the pegs
256 allows the outside lips 260 to be pushed toward each other when
the pegs 256 are advanced in a pair of bores 266 formed in a femur
268. The bores 266 have a first length L1 with a diameter D1, which
is close to diameter d1, and a second length L2 with a larger
diameter D2. As the pegs 256 advance through the first length L1 of
the bores 266, the outside lips 260 are pushed toward each other to
give the pegs 256 an overall diameter less than D1, allowing
advancement of the pegs 256 through the bores 266. When the pegs
256 advance such that the max diameters d2 of the lips 260 reach
the second length L2, the lips 260 expand away from each other to
give the pegs 256 an overall diameter close to the max diameter d2.
When this occurs, the pegs 256 cannot easily be pulled away from
the femur 268 as the lips 260 will abut against the femur 268 in
the bores 266 at the intersection of the first length L1 and the
second length L2. The pegs 256 can be made from any material giving
suitable strength for such an application, including PEEK,
titanium, cobalt chrome, resorbable materials or other polymer
materials.
[0060] In certain applications, it may be useful to provide an
orthopaedic implant of the present invention with a way to deliver
drugs and other therapeutic agents to surrounding anatomy
structures. FIG. 23 shows a support body 270 connected to a bone
ingrowth layer 272 that is modified to deliver drugs to surrounding
anatomy structures. The support body 270 is formed from a first
side 274 having an inner surface 276 and an outer surface 278
(shown in FIG. 24) and a second side 280 having an inner surface
282 and an outer surface (not shown) that attaches to the bone
ingrowth layer 272. Both inner surfaces 276, 282 have channels 284,
286 formed within that combine to form a reservoir within the
support body 270 when the first side 274 and second side 280 are
connected. Elution openings 288 are formed in the channels 286 of
the second side 280, and go through the support body 270 to the
bone ingrowth layer 272. These elution openings 288 allow drugs and
therapeutic agents from the reservoir to flow into the porous bone
ingrowth layer 272 and out to surrounding anatomy structures. Each
side 274, 280 can have a port channel 290 that extends through the
support body 270 to form a port 292 (shown in FIG. 24) that allows
for refilling the reservoir. FIGS. 24 and 25 show an orthopaedic
implant 294 incorporating the support body 270 that is modified for
drug delivery. As can be seen, the outer surface 278 of the first
side 274 has a recess 296 formed therein to allow for a reversible
connection of an articulating tray 298. The outer surface 278 can
also be configured to irreversibly connect to the articulating tray
298. When the reservoir of the support body 270 is full, a stopper
300 can be inserted in the port 292 to prevent drugs or therapeutic
agents from leaking out of the reservoir. FIG. 26 shows the
orthopaedic implant 294 fixated on a tibia 302 according to
embodiments of the present invention, but the orthopaedic implant
294 could also be fixated on a femur according to embodiments of
the present invention. FIG. 27 shows the orthopaedic implant 294
with a refill interface 304, rather than the stopper 300, inserted
in the port 292. The refill interface 304 can be a circular disc
306 placed inside or outside of a patient with an opening 308
connected to a tube 310 that goes into the reservoir to provide a
way to refill the reservoir with drugs or therapeutic agents. A
one-way valve can be placed in the opening 308 to prevent drugs or
therapeutic agents from coming out of the opening 308. Drugs and
therapeutic agents can be injected into the port 292 or refill
interface 304 using a syringe or other similar tool. FIG. 28 shows
an alternative refill interface 320 which is a therapeutic
reservoir 322 with a tube 324 going through the port 292 and into
the reservoir of the support body 270. The therapeutic reservoir
322 can be shaped and placed either within or outside of a patient.
One useful placement of the therapeutic reservoir 322 might be near
a patient's knee, such that when the patient takes a step, forces
from anatomy structures around the reservoir 322 would squeeze the
reservoir 322, designed as a bag, and force drug into the reservoir
of the support body 270 which would then be forced into the bone
ingrowth layer 272.
[0061] While this invention has been described with respect to at
least one embodiment, the present invention 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 invention 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 invention pertains and which fall within the limits of
the appended claims.
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