U.S. patent application number 14/623238 was filed with the patent office on 2015-06-11 for composite orthopedic implant having a low friction material substrate with primary frictional features and secondary frictional features.
This patent application is currently assigned to X-SPINE SYSTEMS, INC.. The applicant listed for this patent is David Louis Kirschman. Invention is credited to David Louis Kirschman.
Application Number | 20150157465 14/623238 |
Document ID | / |
Family ID | 44588178 |
Filed Date | 2015-06-11 |
United States Patent
Application |
20150157465 |
Kind Code |
A1 |
Kirschman; David Louis |
June 11, 2015 |
COMPOSITE ORTHOPEDIC IMPLANT HAVING A LOW FRICTION MATERIAL
SUBSTRATE WITH PRIMARY FRICTIONAL FEATURES AND SECONDARY FRICTIONAL
FEATURES
Abstract
An orthopedic implant comprising a substrate material adapted to
provide the orthopedic implant. The implant has a primary friction
area located on or integral with the substrate material. The
primary friction area defining an engagement surface having a
primary frictional feature. A secondary friction area is located on
or integral with the engagement surface and defining a second
frictional feature. The primary friction area and the secondary
friction area defining a friction interface zone between the
orthopedic implant and at least one bone. The secondary friction
area increases a friction of the engagement surface and modulus of
elasticity to enhance the frictional engagement between the
engagement surface and the at least one bone.
Inventors: |
Kirschman; David Louis;
(Dayton, OH) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Kirschman; David Louis |
Dayton |
OH |
US |
|
|
Assignee: |
X-SPINE SYSTEMS, INC.
Miamisburg
OH
|
Family ID: |
44588178 |
Appl. No.: |
14/623238 |
Filed: |
February 16, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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14154577 |
Jan 14, 2014 |
8979934 |
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14623238 |
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13184856 |
Jul 18, 2011 |
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14154577 |
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61365912 |
Jul 20, 2010 |
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Current U.S.
Class: |
623/17.16 |
Current CPC
Class: |
A61F 2002/30448
20130101; A61F 2002/30838 20130101; A61F 2002/30906 20130101; A61F
2002/30968 20130101; A61F 2002/30789 20130101; A61F 2250/0021
20130101; A61F 2310/00407 20130101; A61F 2310/00413 20130101; A61F
2/30771 20130101; A61F 2002/30841 20130101; A61F 2002/30922
20130101; A61F 2002/30451 20130101; A61F 2/447 20130101; A61F
2002/30929 20130101; A61F 2002/30321 20130101; A61F 2/3094
20130101; A61F 2002/30014 20130101; A61F 2/4611 20130101; A61F
2002/30904 20130101; A61F 2002/3092 20130101; A61F 2/30767
20130101; A61F 2002/30892 20130101; A61F 2002/30024 20130101; A61F
2002/30769 20130101 |
International
Class: |
A61F 2/44 20060101
A61F002/44; A61F 2/30 20060101 A61F002/30 |
Claims
1. An orthopedic implant comprising: a substrate material adapted
to provide the orthopedic implant; a primary friction area located
on or integral with said substrate material, said primary friction
area having a primary surface having a primary frictional feature;
and a secondary friction area located on or integral with said
primary surface and defining a secondary frictional feature; said
primary friction area and said secondary friction area defining a
friction interface zone, said secondary friction area increasing a
friction of said primary surface to enhance the frictional
engagement between said primary surface and at least one bone;
wherein said primary surface defines a plurality of teeth or
serrations; wherein said secondary frictional feature defines a
plurality of teeth, points or peaks located on or integral with
said primary friction area.
2. The orthopedic implant as recited in claim 1 wherein said
primary friction area having a primary friction surface that is at
least one of machined, molded, extruded, sintered or deposited
substrate.
3. The orthopedic implant as recited in claim 2 wherein said
deposited substrate is a polymeric substrate.
4. The orthopedic implant as recited in claim 2 wherein said
primary friction surface defines a plurality of teeth or
serrations.
5. The orthopedic implant as recited in claim 4 wherein said
secondary friction area that is at least one of machined, molded,
extruded, sintered or deposited substrate.
6. The orthopedic implant as recited in claim 4 wherein said
secondary friction area comprises at least one of a microscopically
or macroscopically rough surface.
7. The orthopedic implant as recited in claim 1 wherein said
secondary friction area is regular in shape.
8. The orthopedic implant as recited in claim 1 wherein said
secondary friction area is irregular in shape.
9. The orthopedic implant as recited in claim 1 wherein said
substrate material is made from a thermoplastic.
10. The orthopedic implant as recited in claim 9 wherein said
thermoplastic is a polyetheretherketone (PEEK).
11. The orthopedic implant as recited in claim 1 wherein a modulus
of elasticity of said substrate material is less than or equivalent
to bone.
12. The orthopedic implant as recited in claim 11 wherein said
substrate material has a low coefficient of friction with bone.
13. The orthopedic implant as recited in claim 1 wherein at least
one of said primary friction area or said secondary friction area
being made from a metal or metallic alloy.
14. The orthopedic implant as recited in claim 1 wherein at least
one of said primary friction area or said secondary friction area
having a modulus of elasticity that is the same as or greater than
bone.
15. The orthopedic implant as recited in claim 11 wherein said at
least one of said primary friction area or said secondary friction
area having a modulus of elasticity that the same as or greater
than bone.
16. The orthopedic implant as recited in claim 1 wherein at least
one of said primary friction area or said secondary friction area
comprising a higher coefficient of friction with bone.
17. The orthopedic implant as recited in claim 16 wherein at least
one of said primary friction area or said secondary friction area
having a modulus of elasticity that the same as or greater than
bone.
18. The orthopedic implant as recited in claim 1 wherein said
primary friction area comprising a higher coefficient of friction
with bone and said secondary friction area comprising a higher
coefficient of friction than said primary friction area.
19. The orthopedic implant as recited in claim 1 wherein said
primary friction area having a modulus of elasticity that the same
as or greater than bone and said secondary friction area having a
modulus of elasticity that is the same or greater than said primary
friction area.
20. The orthopedic implant as recited in claim 1 wherein said
secondary frictional feature is integral with, welded to, adhered
to or otherwise affixed to said primary frictional feature.
21. The orthopedic implant as recited in claim 1 wherein said
secondary frictional feature is sprayed onto, melted to or applied
to said primary friction area.
22. The orthopedic implant as recited in claim 21 wherein said
secondary frictional feature is defined by particles that are at
least one of round, not round or acicular, circular, coarse,
acyclic.
23. The orthopedic implant as recited in claim 22 wherein said
particles are continuous or discontinuous or discrete on at least a
portion of said primary frictional feature.
24. The orthopedic implant as recited in claim 1 wherein said
secondary frictional feature defines a plurality of teeth, points
or peaks are located on or integral with said primary friction
area.
25. The orthopedic implant as recited in claim 24 wherein said
plurality of teeth, points or peaks are neither regular nor
symmetrical.
26. The orthopedic implant as recited in claim 24 wherein said
plurality of teeth, points or peaks are regular and
symmetrical.
27. The orthopedic implant as recited in claim 1 wherein said
primary frictional feature and said secondary frictional feature
are made from different materials.
28. The orthopedic implant as recited in claim 1 wherein said
primary frictional feature and said secondary frictional feature
are made from the same materials.
29. The orthopedic implant as recited in claim 1 wherein said at
least one of said primary frictional feature, said secondary
frictional feature or said substrate material is made from a
different material than the others.
30. The orthopedic implant as recited in claim 1 wherein said
secondary frictional feature increases a coefficient of friction of
said orthopedic implant and bone.
31. The orthopedic implant as recited in claim 1 wherein said
orthopedic implant is a spinal implant.
32. The orthopedic implant as recited in claim 31 wherein said
spinal implant is a cage.
33. The orthopedic implant as recited in claim 1 wherein said
secondary frictional feature is a deposit onto said primary
surface.
34. The orthopedic implant as recited in claim 33 wherein said
deposit is a plasma vapor deposition deposit.
35. The orthopedic implant as recited in claim 33 wherein said
primary surface defines a plurality of teeth or serrations and said
deposit is applied to surfaces of one or more of said plurality of
teeth or serrations.
36. An orthopedic implant comprising: a body comprising a composite
material; a first friction area situated between the body and bone
of a patient when the orthopedic implant is implanted in the
patient, said first friction area comprising a plurality of teeth
or serrations; and a second friction area associated with said
first friction area for directly engaging said bone; wherein said
second friction area defines a plurality of teeth, points or peaks
located on or integral with said first friction area; each of said
first and second friction areas for improving a frictional
engagement between said bone and said orthopedic implant.
37. A method for improving a frictional interface between an
implant and bone of a patient, comprising the steps of: processing
a body to comprise a primary friction feature; and processing said
body to comprise a secondary friction feature directly located on
or integral with said primary friction feature; wherein said
secondary friction feature defines a plurality of teeth, points or
peaks that are located on or integral with said primary friction
feature.
Description
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application is a continuation of U.S.
application Ser. No. 14/154,577 filed Jan. 14, 2014, which is a
continuation of U.S. application Ser. No. 13/184,856 filed Jul. 18,
2011, which claims priority to provisional U.S. Application Ser.
No. 61/365,912 filed Jul. 20, 2010, to which Applicant claims the
benefit of the earlier filing date. These applications are
incorporated herein by reference and made a part hereof.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a composite orthopedic implant
having a low friction material substrate with primary frictional
features and secondary frictional features.
[0004] 2. Description of the Related Art
[0005] The placement of spinal implants between vertebrae is a
common surgical procedure. A number of such spinal implants, which
are generally hollow and box-shaped or cylindrical, have been
developed. One risk of such procedures is the post-operative
expulsion or dislocation of the implanted device. There is a need
to increase the frictional forces between the device and the bone
surface.
[0006] The most advantageous material for the manufacture of
intervertebral spinal implants is thermoplastic polymer, of which
the most commonly used is polyetheretherketone (PEEK). This
material has proven biocompatibility with human tissue and is
biomechanically strong enough to withstand long-term cyclical
loading as occurs within the spine. This type of material has a
modulus of elasticity similar to bone, reducing the probability of
bone subsidence which can occur with harder metallic implants. A
significant problem, however, with the use of such polymeric spinal
implants is inherent low levels of bone-device surface interaction.
Machined or molded polymeric materials tend to have relatively high
levels of lubricity, elasticity, and smoothness which conspire to
reduce friction at the bone-device interface. This can result in
undesirably low frictional forces between bone and the implanted
device. Several parties have attempted to address this issue by
adding large frictional features to the polymer implant. These
features are typically exemplified by surface teeth of various
designs. Although surface teeth increase interface friction
somewhat, the underlying challenges of lubricity, smoothness and
elasticity remain.
[0007] What is needed, therefore, is a polymer implant that builds
upon the current state of the art.
SUMMARY OF THE INVENTION
[0008] One object of an embodiment is to provide simple frictional
features that add a metallic surface material which has features of
low lubricity, low elasticity and secondary frictional features.
Such a design will maintain the desirable biomechanical properties
of the polymeric implant itself while addressing frictional
shortcomings at the bone-device interface. Physical properties of
the metallic surface can be further optimized using dispersed
deposition techniques onto the polymeric substrate.
[0009] A composite bone-device interface used, in its preferred
embodiment, in an orthopedic implant for the support of spinal
vertebrae. The interface is manufactured from, in its preferred
embodiment, a combination of biocompatible materials, which
comprise a bone-device interface zone. The interface zone comprises
a relatively low friction polymeric substrate material and primary
frictional features. The primary frictional features further
comprise a high-friction surface material containing secondary
frictional features.
[0010] One object of one embodiment is to provide a primary
friction feature in combination with a secondary friction
feature.
[0011] Another object is to provide an embodiment where the primary
friction feature is integral with the body and comprises the same
material as the body, such as a polymeric substrate, whereas the
secondary friction feature which is integral with, applied to,
deposited on or otherwise adhered to the primary friction feature
is of a different substrate, such as a metal or a metal alloy.
[0012] Still another object is to provide a surgical implant having
improved frictional engagement at the bone-implant engaging
interfaces.
[0013] Still another object is to provide an embodiment wherein the
secondary frictional features are plasma vapor depositions on the
primary frictional features.
[0014] Still another embodiment is to provide an implant having a
body with both primary frictional features and secondary frictional
features.
[0015] Yet another object of one embodiment is to provide primary
and secondary frictional features in the form of teeth or
serrations that can be regular or irregular in shape, discontinuous
or continuous or otherwise have different or the same shape or
configuration with respect to each other.
[0016] Another object of an embodiment is to provide secondary
frictional features in the form of elongated teeth that are
situated on or integral with the primary frictional features, which
in one embodiment are also teeth, and which are either regular and
uninterrupted or irregular and interrupted.
[0017] In one aspect, one embodiment comprises an orthopedic
implant comprising a substrate material adapted to provide the
orthopedic implant, a primary friction area located on or integral
with the substrate material, the primary friction area having a
primary surface having a primary frictional feature, and a
secondary friction area located on or integral with the primary
surface and defining a secondary frictional feature, the primary
friction area and the secondary friction area defining a friction
interface zone, the secondary friction area increasing a friction
of the primary surface to enhance the frictional engagement between
the primary surface and at least one bone, wherein the primary
surface defines a plurality of teeth or serrations, wherein the
secondary frictional feature defines a plurality of teeth, points
or peaks located on or integral with the primary friction area.
[0018] In another aspect, another embodiment comprises an
orthopedic implant comprising a body comprising a composite
material, a first friction area situated between the body and bone
of a patient when the orthopedic implant is implanted in the
patient, the first friction area comprising a plurality of teeth or
serrations, and a second friction area associated with the first
friction area for directly engaging the bone, wherein the second
friction area defines a plurality of teeth, points or peaks located
on or integral with the first friction area, each of the first and
second friction areas for improving a frictional engagement between
the bone and the orthopedic implant.
[0019] In yet another aspect, another embodiment comprises a method
for improving a frictional interface between an implant and bone of
a patient, comprising the steps of processing a body to comprise a
primary friction feature, and processing the body to comprise a
secondary friction feature directly located on or integral with the
primary friction feature, wherein the secondary friction feature
defines a plurality of teeth, points or peaks that are located on
or integral with the primary friction feature.
[0020] This invention, including all embodiments shown and
described herein, could be used alone or together and/or in
combination with one or more of the features covered by one or more
of the claims set forth herein, including but not limited to one or
more of the features or steps mentioned in the following bullet
list and the claims: [0021] The orthopedic implant wherein the
primary friction area having a primary friction surface that is at
least one of machined, molded, extruded, sintered or deposited
substrate. [0022] The orthopedic implant wherein the deposited
substrate is a polymeric substrate. [0023] The orthopedic implant
wherein the primary friction surface defines a plurality of teeth
or serrations. [0024] The orthopedic implant wherein the secondary
friction area that is at least one of machined, molded, extruded,
sintered or deposited substrate. [0025] The orthopedic implant
wherein the secondary friction area comprises at least one of a
microscopically or macroscopically rough surface. [0026] The
orthopedic implant wherein the secondary friction area is regular
in shape. [0027] The orthopedic implant wherein the secondary
friction area is irregular in shape. [0028] The orthopedic implant
wherein the substrate material is made from a thermoplastic. [0029]
The orthopedic implant wherein the thermoplastic is a
polyetheretherketone (PEEK). [0030] The orthopedic implant wherein
a modulus of elasticity of the substrate material is less than or
equivalent to bone. [0031] The orthopedic implant wherein the
substrate material has a low coefficient of friction with bone.
[0032] The orthopedic implant wherein at least one of the primary
friction area or the secondary friction area being made from a
metal or metallic alloy. [0033] The orthopedic implant wherein at
least one of the primary friction area or the secondary friction
area having a modulus of elasticity that is the same as or greater
than bone. [0034] The orthopedic implant wherein at least one of
the primary friction area or the secondary friction area comprising
a higher coefficient of friction with bone. [0035] The orthopedic
implant wherein the primary friction area comprising a higher
coefficient of friction with bone and the secondary friction area
comprising a higher coefficient of friction than the primary
friction area. [0036] The orthopedic implant wherein the primary
friction area having a modulus of elasticity that the same as or
greater than bone and the secondary friction area having a modulus
of elasticity that is the same or greater than the primary friction
area. [0037] The orthopedic implant wherein the secondary
frictional feature is integral with, welded to, adhered to or
otherwise affixed to the primary frictional feature. [0038] The
orthopedic implant wherein the secondary frictional feature is
sprayed onto, melted to or applied to the primary friction area.
[0039] The orthopedic implant wherein the secondary frictional
feature is defined by particles that are at least one of round, not
round or acicular, circular, coarse, acyclic. [0040] The orthopedic
implant wherein the particles are continuous or discontinuous or
discrete on at least a portion of the primary frictional feature.
[0041] The orthopedic implant wherein the secondary frictional
feature defines a plurality of teeth, points or peaks are located
on or integral with the primary friction area. [0042] The
orthopedic implant wherein the plurality of teeth, points or peaks
are neither regular nor symmetrical. [0043] The orthopedic implant
wherein the plurality of teeth, points or peaks are regular and
symmetrical. [0044] The orthopedic implant wherein the primary
frictional feature and the secondary frictional feature are made
from different materials. [0045] The orthopedic implant wherein the
primary frictional feature and the secondary frictional feature are
made from the same materials. [0046] The orthopedic implant wherein
the at least one of the primary frictional feature, the secondary
frictional feature or the substrate material is made from a
different material than the others. [0047] The orthopedic implant
wherein the secondary frictional feature increases a coefficient of
friction of the orthopedic implant and bone. [0048] The orthopedic
implant wherein the orthopedic implant is a spinal implant. [0049]
The orthopedic implant wherein the spinal implant is a cage. [0050]
The orthopedic implant wherein the secondary frictional feature is
a deposit onto the primary surface. [0051] The orthopedic implant
wherein the deposit is a plasma vapor deposition deposit. [0052]
The orthopedic implant wherein the primary surface defines a
plurality of teeth or serrations and the deposit is applied to
surfaces of one or more of the plurality of teeth or serrations.
[0053] The orthopedic implant wherein the body and the first
friction area comprise have a modulus of elasticity that is lower
than a modulus of elasticity of the second friction area. [0054]
The orthopedic implant wherein the second friction area defines a
frictional engaging surface that increases a coefficient of
friction between the first friction area and the bone. [0055] The
orthopedic implant wherein body is made from a polymeric material,
and at least one of the first or second friction areas comprises a
metallic or metallic alloy. [0056] The orthopedic implant wherein
the first friction area defines a plurality of teeth or serrations
and the second friction area defines a layer or coating thereon.
[0057] The orthopedic implant wherein the second friction area is
uninterrupted. [0058] The orthopedic implant wherein the composite
material is made from a thermoplastic. [0059] The orthopedic
implant wherein a modulus of elasticity of the composite material
is less than or equivalent to bone. [0060] The orthopedic implant
wherein a coefficient of friction associated with the composite
material and bone is lower than a coefficient of friction between
the second friction area and the bone. [0061] The orthopedic
implant wherein each of the first friction area and the second
friction area are made from a metal or metallic alloy and the body
is made of a polymer. [0062] The orthopedic implant wherein each of
the first friction area or the second friction area have a modulus
of elasticity that is the same as or greater than bone. [0063] The
orthopedic implant wherein each of the first friction area and the
second friction area comprise a higher coefficient of friction with
bone. [0064] The orthopedic implant wherein the second friction
area is integral with, welded to, adhered to or otherwise affixed
to the first friction area. [0065] The orthopedic implant wherein
the second friction area is sprayed onto, melted to, adhered to or
applied to the first friction area. [0066] The orthopedic implant
wherein the second friction area is defined by particles that are
at least one of round, not round, circular, coarse, acyclic. [0067]
The orthopedic implant wherein the particles are continuous or
discontinuous or discrete on at least a portion of the first
friction area. [0068] The orthopedic implant wherein the second
friction area defines a plurality of points or peaks on the first
friction area. [0069] The orthopedic implant wherein the plurality
of points or peaks are neither regular nor symmetrical. [0070] The
orthopedic implant wherein the plurality of points or peaks are
regular and symmetrical. [0071] The orthopedic implant wherein the
second friction area is a deposit onto the first friction area.
[0072] The orthopedic implant wherein the first friction area
defines a plurality of teeth or serrations and the deposit is
applied to surfaces of one or more of the plurality of teeth or
serrations. [0073] The method wherein the primary friction feature
has a primary friction surface that is at least one of machined,
molded, extruded, sintered or deposited substrate. [0074] The
method wherein the least one of machined, molded, extruded,
sintered or deposited substrate is a polymeric substrate. [0075]
The method wherein the primary friction surface defines a plurality
of teeth or serrations. [0076] The method wherein the secondary
friction feature that is at least one of machined, molded,
extruded, sintered or deposited substrate. [0077] The method
wherein the secondary friction feature comprises at least one of a
microscopically or macroscopically rough surface. [0078] The method
wherein the secondary friction feature is regular in shape. [0079]
The method wherein the secondary friction feature is irregular in
shape. [0080] The method wherein the least one of machined, molded,
extruded, sintered or deposited substrate has a low coefficient of
friction with bone. [0081] The method wherein at least one of the
primary friction surface or the secondary friction feature being a
deposit on the primary friction surface of a metal or metallic
alloy. [0082] The method wherein the secondary friction feature
defines a plurality of teeth, points or peaks on the primary
friction surface. [0083] The method wherein the method comprises
the step of depositing the secondary friction feature onto the
primary friction feature. [0084] The method as wherein the
depositing step is performed using plasma vapor deposition.
[0085] These and other objects and advantages will be apparent from
the following description, the accompanying drawings and the
appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0086] FIG. 1 is a perspective view of one embodiment;
[0087] FIG. 1A is sectional view taken along the line 1A-1A in FIG.
1;
[0088] FIG. 2 is an enlarged view of a portion of the implant shown
in FIG. 1 showing details of the primary friction feature and
secondary friction feature;
[0089] FIG. 3 is a perspective view of the enlargement shown in
FIG. 2;
[0090] FIG. 4 is a sectional view taken along the line 4-4 in FIG.
5 illustrating the secondary friction feature in the form of a
deposit or coating on the primary friction feature;
[0091] FIG. 5 is a view of another embodiment showing the primary
friction feature as teeth and the secondary friction feature as a
deposit or coating;
[0092] FIGS. 6A-6B is a view of another embodiment of the invention
showing the elongated teeth that are interrupted or spaced in the
direction of arrow A;
[0093] FIG. 7 is a view of another embodiment of the invention
similar to FIG. 5;
[0094] FIGS. 8A-8B are views of the secondary friction features
having a curved or serpentine shape;
[0095] FIGS. 9A-9B illustrate an embodiment wherein the primary
friction features have a curved or serpentine shape while the
secondary friction features have a generally linear (FIG. 9A) shape
or a curved (FIG. 9B) shape;
[0096] FIGS. 10A-10B illustrate another embodiment similar to FIGS.
4 and 5 wherein the deposit or coating is selectively placed;
[0097] FIG. 11 illustrates the primary friction feature and
secondary friction feature in the form of teeth having different
shapes, pitches, pitch thickness and the like; and
[0098] FIGS. 12A-12B illustrate embodiments wherein the primary
friction feature or secondary friction feature are interrupted
(FIG. 12A) along their longitudinal length and wherein the primary
friction feature is not interrupted along its longitudinal length,
but the secondary friction feature is interrupted (FIG. 12B).
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0099] Referring now to FIGS. 1-5, a first embodiment of an
orthopedic implant 10 is shown. The orthopedic implant 10 comprises
a body 12 that is adapted to provide or define the orthopedic
implant 10. In the illustration being described, the orthopedic
implant 10 could be a spinal implant, such as a cage, plate or
other implant wherein surfaces of the orthopedic implant 10 engage,
for example, bone of a patient. In one application, the orthopedic
implant 10 is situated between adjacent vertebrae (not shown) of a
patient. In the illustration being described, the orthopedic
implant 10 comprises the body 12 made from a substrate or composite
material, such as a polymeric material. The polymeric material may
be a thermoplastic material, such as polyetheretherketone (PEEK).
The substrate or composite material has a low coefficient of
friction with bone.
[0100] The orthopedic implant 10 defines an orthopedic cage 11 in
this illustration having a plurality of walls 14a, 14b, 14c and
14d. The walls 14a and 14c have windows 18 and 20 as shown. The
orthopedic implant 10 has a plurality of walls 21 that define tool
apertures 22 for receiving a tool (not shown) for placement of the
orthopedic implant 10, for example, between adjacent vertebrae (not
shown) in the patient.
[0101] The orthopedic implant 10 further has a first end 12a and a
second end 12b. As best illustrated in FIGS. 2-5, note that the
orthopedic implant 10 comprises a first or primary friction area,
layer or feature 24 applied to, adhered to or integrally formed on
each ends 12a and 12b. In the illustration, the body 12 defines a
cage 11 that has four bone-engaging areas or surfaces 12a1, 12a2,
12b1 and 12b2.
[0102] In the illustration being described, the first or primary
friction area, layer or feature 24 comprises or is adapted to
define a first plurality of teeth or serrations 26 which are
integrally formed in the surfaces 12a1, 12a2, 12b1 and 12b2 as
shown. The body 12 is machined, molded, extruded, centered, cast or
has a deposited substrate that is applied to the body 12 to provide
or define the first or primary friction area, layer or feature 24.
Although not shown, it should be appreciated that the first or
primary friction area, layer or feature 24 may be separate from and
non-integral with the body 12, for example, but that is secured
thereto by a weld, bond adhesive or other type of fixation. In the
illustration being described relative to FIGS. 1-3, the first or
primary friction area, layer or feature 24 comprises the first
plurality of teeth or serrations 26 that are integral with the body
12 and both are made of the same polymeric substrate, such as
polyetheretherketone (PEEK). Alternatively, the body 12 could be
made from a polymeric substrate while the first or primary friction
area, layer or feature 24 may comprise a metallic or metallic alloy
that is applied or, adhered to or otherwise affixed or secured to
the body 12. After the orthopedic implant 10 is implanted into the
patient, the first or primary friction area, layer or feature 24
becomes situated between the body 12 and the bone of the patient,
such as the adjacent vertebra (not shown).
[0103] As mentioned earlier, the first or primary friction area,
layer or feature 24 comprises the first plurality of teeth or
serrations 26 that are integral with both ends 12a and 12b of the
body 12, and each of the areas or surfaces 12a1, 12a2, 12b1 and
12b2 have the first plurality of teeth or serrations 26. For ease
of illustration, portions of the first plurality of teeth or
serrations 26 on the surface 12a2 are shown fragmentarily and
enlarged in FIGS. 2 and 3, but it should be understood that the
first plurality of teeth or serrations 26 of the first or primary
friction area, layer or feature 24 on the other portions of surface
12a2 and on the other surfaces 12a1, 12b1 and 12b2 are
substantially the same in this embodiment.
[0104] The orthopedic implant 10 further comprises a second or
secondary friction area, layer or feature 28 associated with the
first or primary friction area, layer or feature 24. In the
illustration being described, the second or secondary friction
area, layer or feature 28 is applied to, deposited on, adhered to,
bonded, located on or integral with the first or primary friction
area, layer or feature 24 as shown. In the illustration being shown
in FIGS. 1-3, the first or primary friction area, layer or feature
24 and the second or secondary friction area, layer or feature 28
cooperate to define a plurality of friction interface zones 30
(FIGS. 1-1A).
[0105] The second or secondary friction area, layer or feature 28
is applied to, deposited on, adhered to, located on or adhered to
teeth surfaces, such as surfaces 26a and 26b (FIG. 2) of each of
the first plurality of teeth or serrations 26 on the surfaces 12a1,
12a2, 12b1 and 12b2 where the orthopedic implant 10 engages bone
and increases a friction between each of the first plurality of
teeth or serrations 26 and the bone of the patient. It has been
found that the enhanced frictional engagement facilitates
maintaining the position of the orthopedic implant 10 in the
patient. For example, it is desirable that the cage 11 illustrated
in FIGS. 1 to 5 not move after it is implanted in the patient, and
the second or secondary friction area, layer or feature 28 enhances
the frictional engagement between the first or primary friction
area, layer or feature 24 and the bone of the patient to prevent or
minimize such movement.
[0106] The first or primary friction area, layer or feature 24
comprises a first or primary friction feature in the form of the
first plurality of teeth or serrations 26, and the second or
secondary friction area, layer or feature 28 comprises a second or
secondary friction feature that enhances the orthopedic implant's
10 friction interface zone 30. In the embodiment of FIGS. 1-3,
6A-6B, 7, 8A-8B, 9A-9B, 11 and 12A-12B, the second or secondary
friction area, layer or feature 28 comprises a second plurality of
teeth or serrations 32 integral with, deposited on, adhered to or
otherwise applied to one or more of the first plurality of teeth or
serrations 26 as shown. The body 12, the first or primary friction
area, layer or feature 24 and the second or secondary friction
area, layer or feature 28 is manufactured from, in its preferred
embodiment, a combination of bio-compatible materials, including
but not limited to, at the friction interface zone 30.
[0107] In the illustration being described, the second or secondary
friction area, layer or feature 28 may comprise a microscopically
and/or macroscopically rough or porous surface, which enhances the
frictional engagement between the first or primary friction area,
layer or feature 24 and the bone of the patient. The rough surface
may be provided by, for example, sand blasting, coating, plasma
spraying, vapor deposition, adhering a frictional layer, peening or
even laser shock peening.
[0108] The secondary friction features may comprise a machined,
molded, extruded, sintered or deposited surface material. In the
illustration of FIGS. 4-5, 10A and 10B, the deposited surface
material may comprise a coating or deposition that is sprayed onto,
melted to or otherwise applied or adhered to the primary surface
26a of the first or primary friction area, layer or feature 24. In
the embodiment shown in FIGS. 4, 5, 7 and 10A-10B, the coating or
deposition is a plasma vapor deposition applied using a
conventional plasma vapor deposition process. Thus, it should be
understood that the second or secondary friction area, layer or
feature 28 may be integral with, welded to, machined into, adhered
to, deposited on or otherwise affixed, processed or applied to the
first or primary friction area, layer or feature 24.
[0109] In the illustrations being described, the body 12, the first
or primary friction area, layer or feature 24 and the second or
secondary friction area, layer or feature 28 may be made from the
same bio-compatible material or one or more of them can comprise or
be made from different bio-compatible materials. In one embodiment,
each of the body 12 and the first or primary friction area, layer
or feature 24 are made of a bio-compatible polymeric substrate,
such as polyetheretherketone (PEEK), while the second or secondary
friction area, layer or feature 28 is comprised of a metal or
metallic alloy. In the embodiments of FIGS. 1-5, the body 12 and
the first or primary friction area, layer or feature 24 are
integral and monolithically formed and are made from the same PEEK
material, while the second or secondary friction area, layer or
feature 28 is a metallic material, metal, or metallic alloy, such
as titanium, cobalt or associated alloys. It should be understood
that the body 12, first or primary friction area, layer or feature
24 and the second or secondary friction area, layer or feature 28
could be the same material, such as a polymer, a metal or metal
alloy or different materials.
[0110] The body 12 and the first or primary friction area, layer or
feature 24 comprise the polymeric substrate have a relatively low
modulus of elasticity and/or a modulus of elasticity equivalent to
bone while the second or secondary friction area, layer or feature
28 has a higher modulus elasticity and has a modulus of elasticity
that is higher than bone. It should be understood, however, that
both of the first or primary friction area, layer or feature 24
and/or the second or secondary friction area, layer or feature 28
could comprise a relatively high modulus of elasticity or a modulus
of elasticity that is higher than bone if desired.
[0111] Thus, at least one or both of the first or primary friction
area, layer or feature 24 or the second or secondary friction area,
layer or feature 28 may comprise a relatively high coefficient of
friction with bone, while the underlying substrate or body 12 and
the first or primary friction area, layer or feature 24 may
comprise a relatively low modulus of elasticity and low coefficient
of friction relative to bone. In the embodiment of FIGS. 1-5, the
second or secondary friction area, layer or feature 28 comprises a
higher coefficient of friction and higher modulus of elasticity
compared to the first or primary friction area, layer or feature 24
and body 12 which facilitate the frictional engagement and locking
of the orthopedic implant 10 in the patient, such as between the
patient's vertebra.
[0112] Thus, it should be understood that while the body 12 and the
first or primary friction area, layer or feature 24 and the second
or secondary friction area, layer or feature 28 may be made from
the same materials having the same coefficient of friction and
modulus of elasticity, they could comprise different materials
which have either the same or different coefficients of friction
and/or the same or different moduli of elasticity. Also, the first
or primary friction area, layer or feature 24 and the second or
secondary friction area, layer or feature 28 could be different
materials and their respective modulus of elasticity and
coefficients of friction relative to bone may be different as
mentioned earlier.
[0113] Again, it should be understood that one advantage of the
embodiments being described is that they enhance the frictional
engagement of the orthopedic implant 10 when it is implanted in the
patient. Thus, the orthopedic implant 10 having the first or
primary friction area, layer or feature 24 comprising the second or
secondary friction area, layer or feature 28 will comprise a higher
modulus of elasticity and higher coefficient of friction compared
to bone.
[0114] Advantageously, the polymers or polymeric materials used in
the past may be utilized in manufacturing the body 12 and the
shortcomings of such materials can be used to provide the
orthopedic implant 10 having the body 12 that has relatively high
levels of lubricity, elasticity and smoothness, but which have been
adapted, machined or processed as provided herein to provide
relatively high modulus of elasticity and high coefficients of
friction at the orthopedic implant 10-bone interface by providing
the first or primary friction area, layer or feature 24 with the
second or secondary friction area, layer or feature 28 as described
herein.
[0115] As mentioned earlier, the first or primary friction area,
layer or feature 24 may be machined, molded, integral extruded,
sintered or deposited onto the body 12. The first or primary
friction area, layer or feature 24 may be separate from or integral
with the body 12 as mentioned earlier. Likewise, the second or
secondary friction area, layer or feature 28 may be machined,
molded, extruded, sintered or deposited directly on the first or
primary friction area, layer or feature 24 and may also be separate
from or integral with it. For example, the second or secondary
friction area, layer or feature 28 may be sprayed onto, deposited
on, melted to, or otherwise applied to or adhered to the first
plurality of teeth or serrations 26 surfaces, such as surfaces 26a
and 26b of each of the first plurality of teeth or serrations 26,
and/or on each surface 12a1, 12a2, 12b1 and 12b2 having the first
or primary friction area, layer or feature 24, thereby enhancing
the frictional engagement between the orthopedic implant 10 and the
bone. As mentioned earlier, the second or secondary friction area,
layer or feature 28 may be deposited on these surfaces using a
plasma vapor deposition process.
[0116] Returning to the embodiment of FIGS. 1-3, the first or
primary friction area, layer or feature 24 comprises the first
plurality of teeth or serrations 26 that have peaks and valleys in
cross section and are elongated, with each tooth or serration being
generally the same in shape and dimension. Likewise, the second or
secondary friction area, layer or feature 28 is defined by the
second plurality of teeth or serrations 32 that are machined into,
integral with, adhered to or applied directly to the surfaces 26a
and 26b of the first plurality of teeth or serrations 26 as
illustrated in FIGS. 1-3. In the illustration being described, the
plurality of teeth 32 are thermally bonded, adhered, impregnated,
embedded on or in into the teeth 26. For ease of illustration, FIG.
2 shows bonding of the teeth or serrations 32 to teeth or
serrations 26 with an adhesive 37, but it should be understood that
the teeth may be adhered by other means. As with the first
plurality of teeth or serrations 26, the second plurality of teeth
or serrations 32, such as teeth 32a and 32b in FIG. 2, may each
comprise generally the same shape and be elongated along the
longitudinal axis and continuous as shown in FIG. 3. In other
words, the first and second pluralities of teeth or serrations 26
and 32 may be regular in shape.
[0117] Note that the first plurality of teeth or serrations 26 are
elongated and comprise surfaces 26a and 26b comprising the rows or
strips 33 of the second plurality of teeth or serrations 32. The
rows or strips 33 are made of metal or a metal alloy, such as
titanium or other biocompatible substance capable of providing a
high-friction layer, in the illustration and adhered to or
overmolded with the body 12.
[0118] In the illustration, the orthopedic implant 10 is inserted
into the patient and the first or primary friction area, layer or
feature 24 and the second or secondary friction area, layer or
feature 28 on surfaces 12a1, 12a2, 12b1 and 12b2 frictionally
engage bone to secure the orthopedic implant 10 in the patient.
[0119] FIGS. 6-9B and 11-12B illustrate other embodiments with like
parts being identified with the same part numbers except that one
or more legends or prime marks ("'") have been added to distinguish
the various embodiments of these figures.
[0120] Note that the first plurality of teeth or serrations 26' in
FIG. 11 comprises different cross-sectional shapes and sizes. Thus,
the first and second pluralities of teeth or serrations 26' and 32'
may be adapted to be irregular in shape, and the first plurality of
teeth or serrations 26' in FIG. 11 could comprise different
cross-sectional shapes and sizes. For example, note that tooth 26c'
has a different shape and size compared to tooth 26d'.
[0121] Likewise, the shape or size of each individual tooth, such
as teeth 32a' and 32b' (FIG. 11) of the second plurality of teeth
or serrations 32' may be different. Thus, the individual teeth in
each of the first and second plurality of teeth or serrations 26'
and 32' could be the same or have different shapes, and they could
have different pitches, depths, widths and the like and will be
described later herein.
[0122] As mentioned, while the embodiment in FIGS. 1-3 illustrate
that each of the first plurality of teeth or serrations 26 and the
second plurality of teeth or serrations 32 are generally regular
and uninterrupted as shown, but it should be understood that either
at least one of both of the first and second pluralities of teeth
or serrations 26 and 32 may be non-elongated and interrupted. For
example, FIG. 12A illustrates that both the first plurality of
teeth or serrations 26'' and the second plurality of teeth or
serrations 32'' that are situated on or integral with each of the
first plurality of teeth or serrations 26' are not continuous and
are interrupted along their longitudinal axis. FIG. 12B illustrates
an embodiment where only the second plurality of teeth or
serrations 32'' is interrupted, but not the first plurality of
teeth or serrations 26''. Alternatively, while the embodiments
shown in FIGS. 12A and 12B illustrates first and second pluralities
of teeth or serrations 26'' and 32'' being interrupted along their
longitudinal axis, it should be understood that there may be a
mixture of interrupted and uninterrupted teeth if desired.
[0123] FIGS. 6A-6B illustrate still another embodiment wherein the
second plurality of teeth or serrations 32'''' are spaced or
interrupted in the direction of arrow A in FIG. 6A-6B as shown. In
this regard, it should be appreciated that one or both surfaces of
each tooth, such as surfaces 26a'''' and 26b'''' in FIGS. 6A-6B,
are shown as having at least one or a plurality of the second
plurality of teeth or serrations 32'''' mounted thereon or integral
therewith. They are separately shown, but it should be understood
that either one or both surfaces of the plurality of teeth or
serrations 26'''', such as surfaces 26a'''' and 26b'''', may either
have or not have less teeth or one or more of the second plurality
of teeth or serrations 32''''.
[0124] Still other embodiments are shown in FIGS. 8A-8B and 9A-9B
wherein the second plurality of teeth or serrations 32'''' are
shown in a curved or serpentine and non-linear shape. It should be
understood that the first plurality of teeth or serrations 26'''''
could also be provided in a serpentine or curved shape, with the
second plurality of teeth or serrations 32''''' as shown. Although
not shown, the first plurality of teeth or serrations 26''''' could
be generally serpentine or curved (FIGS. 9A-9B) with the second
plurality of teeth or serrations 32''''' also having a serpentine
or curved shape. FIGS. 8A-8B illustrate the first teeth or
serrations 26 being generally linear with the second teeth or
serrations 32 being curved or serpentine.
[0125] Although not shown, it should be appreciated that the
embodiments shown in FIGS. 6, 7, 8A-8B, 9A-9B and 11 could be
provided such that they are continuous and uninterrupted or
discontinuous and interrupted. Likewise, the teeth illustrated in
the figures could be provided such that the first and second
pluralities of teeth or serrations 26 and 32 in the embodiments are
not of the same cross-sectional dimension or shape. As mentioned
earlier relative to FIG. 11, it should be understood that the
individual tooth 26 and 32 could be adapted or provided so that
they are neither regular nor symmetrical when viewed in one or more
of the directions in arrow B, arrow C or arrow D in FIGS. 1-1A.
Thus, individual teeth of both the first plurality of teeth or
serrations 26 and the second plurality of teeth or serrations 32
could have different pitches, depths, widths and the like.
[0126] Referring now to the embodiment shown in FIGS. 4, 5, 10A and
10B, the second or secondary area, layer or feature 28 may be
provided in the form of a deposit or coating 40. As with prior
embodiments, those parts that are the same or similar to the parts
shown in FIGS. 1-1A are identified with the same part number except
that prime marks ("'''") has been added to the part numbers in
FIGS. 4 and 5 and a mark ("VI") has been added to those parts in
the embodiment of FIGS. 10A and 10B. As mentioned earlier, the
second or secondary friction area, layer or feature 28''' coating
or deposit 40''' could be deposited onto, sprayed onto, melted onto
or otherwise applied to the first or primary area, layer or feature
24'''. In the illustration being described relative to FIGS. 4 and
5, the coating 40'' comprises a plurality of particles 42'' that
are deposited onto, adhered to or otherwise applied to surfaces
12a1'', 12a2'', 12b1'' and 12b2''. In this embodiment, the coating
40'' is applied using a plasma layer deposition
[0127] In this regard, the body 12'' defines the orthopedic implant
10'' for implanting into the patient. The first or primary area,
layer or feature 24'' in this embodiment is similar to the
embodiment in FIGS. 1-1A in that each surface 12a1'', 12a2''',
12b1''' and 12b2''' has or defines a plurality of teeth or
serrations 26'''. In the illustration being described, each of the
plurality of teeth or serrations 26''' comprises a first surface
26e''' (FIG. 4) and the second surface 26f''' as shown having the
coating or deposit 40''' of particles 42'''. Note also that areas
or surfaces 12a3''', 12a4''', 12b3''' and 12b4''' (FIG. 5) also
have the coating or deposit 40''' of particles 42. In the
illustration being described, the coating or deposit 40''' is
titanium, cobalt or associated alloys. As previously mentioned, the
teeth or serrations 26 may be asymmetrical to enhance frictional
engagement.
[0128] Thus, each of the ends 12a''' and 12b''' in the illustration
being described comprise the coating or deposit 40''' of particles
42'''. In the illustration shown in FIGS. 4 and 5, note that the
layer or coating 46''' is continuous over the first or primary
area, layer or feature 24''' and on ends 12a''' and 12b''', but it
should be understood that the ends 12a''' and 12b''' could be spot
coated, and less than the entire first or primary area, layer or
feature 24''' may have no deposit or coating thereon. This is
illustrated in FIGS. 10A-10B where some of the areas of the first
teeth or serrations 26, such as the areas 50, may not comprise the
deposit or coating as shown. Stated another way, the coating
40.sup.VI or deposit 40''' may be selectively provided or applied
to those surfaces of the orthopedic implant 10''' that engage
bone.
[0129] In the embodiment of FIG. 7, the surfaces, such as surfaces
32b.sup.VII and 32c.sup.VII of each of the second plurality of
teeth or serrations 32.sup.VII comprises a deposit or coating or
deposit 40.sup.VII of particles 42.sup.VII similar to that shown in
FIG. 5. Thus, it should be understood that the embodiment shown in
FIGS. 4 and 5 illustrates the second or secondary area, layer or
feature 28'' comprising the deposit or coating as shown, whereas
the embodiment illustrated in FIG. 7 shows the first or primary
area, layer or feature 24.sup.VII having the first plurality of
teeth or serrations 26.sup.VII having the second or secondary area,
layer or feature 28.sup.VII in the form of the second plurality of
teeth or serrations 32.sup.VII which themselves have the coating or
deposit 40.sup.VII of particles 42.sup.VII.
[0130] In the illustrations being described, any particles
42.sup.VII that are applied, sprayed, adhered, coated, deposited or
melted onto at least one of the first or primary area, layer or
feature 24.sup.VII or the second or secondary area, layer or
feature 28.sup.VII may be round, not round or circular or
non-circular, coarse, acyclic, and may form a continuous layer or
discontinuous or discreet layer on all or only a portion of the
first or primary area, layer or feature 24.sup.VII or the second or
secondary area, layer or feature 28.sup.VII. As mentioned earlier,
the first or primary area, layer or feature 24.sup.VII and the
second or secondary area, layer or feature 28.sup.VII may be
comprised of the same substance or material or they could comprise
different materials, such as a metallic or metallic alloy as
mentioned earlier herein, or a thermal plastic such as PEEK. In the
illustration of FIGS. 4, 5, 7 and 10A-10B, the layer or coating
46''' is a metallic coating of titanium, cobalt or associated
alloys deposited on the first plurality of teeth or serrations
26''' using plasma vapor deposition.
[0131] Advantageously, the second or secondary area, layer or
feature in all embodiments augments at least a portion or all of
the external first or primary area, layer or feature, such as the
surfaces 26a, 26b of the one or more of the first plurality of
teeth or serrations 26 in the embodiment of FIGS. 1-3 in order to
enhance or add high friction to the engagement surfaces of the
orthopedic implant 10. While traditional implants have engagement
surfaces that engage bone, the embodiments described herein improve
the frictional engagement between the bone and the orthopedic
implant 10 by adding the second or secondary area, layer or feature
28 which provides improved frictional engagement between the
frictional surfaces of the orthopedic implant 10 and bone.
[0132] Advantageously, one advantage of the orthopedic implant 10
as described herein is that it improves the inherently low levels
of bone-orthopedic implant 10 interface and surface interaction.
The primary frictional features described herein add a surface
material, such as a metallic surface material, to the first or
primary friction area, layer or feature 24 which provides low
lubricity, low elasticity and the secondary frictional features
defined by the second or secondary friction area, layer or feature
28. The embodiments described provide or comprise a design that
will maintain the biomechanical properties of the orthopedic
implant 10 while addressing frictional shortcomings of the
orthopedic implant 10 and the interfaces between the bone and the
implants of the past.
[0133] This invention, including all embodiments shown and
described herein, could be used alone or together and/or in
combination with one or more of the features covered by one or more
of the claims set forth herein, including but not limited to one or
more of the features or steps mentioned in the Summary of the
Invention and the claims.
[0134] While the system, apparatus and method herein described
constitute preferred embodiments of this invention, it is to be
understood that the invention is not limited to this precise
system, apparatus and method, and that changes may be made therein
without departing from the scope of the invention which is defined
in the appended claims.
* * * * *