U.S. patent application number 12/328493 was filed with the patent office on 2010-06-10 for joint support and subchondral support system.
Invention is credited to Derek Dee.
Application Number | 20100145451 12/328493 |
Document ID | / |
Family ID | 42231954 |
Filed Date | 2010-06-10 |
United States Patent
Application |
20100145451 |
Kind Code |
A1 |
Dee; Derek |
June 10, 2010 |
JOINT SUPPORT AND SUBCHONDRAL SUPPORT SYSTEM
Abstract
A joint support and subchondral support system for providing
structural and dampening support to damaged subchondral bone in
generalized or discrete arthritis includes a contoured, porous
plate having a variable shaped inner surface, outer surface, and
peripheral surface of variable thickness extending between the
inner surface and the outer surface, suitable for insertion within
the subchondral bone. The inner surface, outer surface and
peripheral surface each have a concave portion and a convex
portion. A guide pin hole or slot is located within the contoured,
porous plate to aid in insertion and placement of the plate over at
least one corresponding guide pin within the subchondral bone. The
joint support and subchondral support system of the present
invention is applicable to many parts of the joint as any area with
cartilage disease has an adjoining subchondral component.
Inventors: |
Dee; Derek; (Rancho Palos
Verdes, CA) |
Correspondence
Address: |
CHAN LAW GROUP LLP
1055 W. 7TH ST,, SUITE 1880
LOS ANGELES
CA
90017
US
|
Family ID: |
42231954 |
Appl. No.: |
12/328493 |
Filed: |
December 4, 2008 |
Current U.S.
Class: |
623/14.12 |
Current CPC
Class: |
A61F 2002/2892 20130101;
A61F 2002/3895 20130101; A61B 17/562 20130101; A61F 2002/30759
20130101; A61F 2002/30171 20130101; A61F 2/30 20130101; A61F
2002/30131 20130101; A61F 2/389 20130101; A61F 2002/30563 20130101;
A61F 2/30756 20130101; A61F 2002/30841 20130101; A61F 2/38
20130101; A61F 2002/30845 20130101; A61F 2/3859 20130101; A61F
2002/2825 20130101 |
Class at
Publication: |
623/14.12 |
International
Class: |
A61F 2/08 20060101
A61F002/08 |
Claims
1. A joint support and subchondral support system for providing
structural and dampening support to damaged subchondral bone
adjacent to a body joint, comprising: a contoured, porous plate
having a variable shaped inner surface, outer surface, and
peripheral surface of variable thickness extending between the
inner surface and the outer surface, suitable for insertion within
the subchondral bone; the inner surface, outer surface and
peripheral surface each having a concave portion and a convex
portion; wherein at least one guide pin hole or slot is located
within the contoured, porous plate to aid insertion and placement
of the plate over at least one corresponding guide pin within the
subchondral bone.
2. The joint support and subchondral support system of claim 1,
wherein the porosity of the contoured plate is within a range of
from about 50 microns to about 20 mm.
3. The joint support and subchondral support system of claim 2,
wherein the contoured, porous plate includes at least one of
micropores, scaffold-like pores, and fibrous matrix material.
4. The joint support and subchondral support system of claim 1,
wherein the contoured, porous plate includes a plurality of surface
dimpling thereon having a radius of from about 50 microns to about
3 mm.
5. The joint support and subchondral support system of claim 1,
wherein the contoured, porous plate includes a plurality of
undersurface pimples thereon having a radius of from about 50
microns to about 3 mm.
6. The joint support and subchondral support system of claim 1,
wherein the contoured, porous plate may be configured to fit flush
with at least one contour of the corresponding subchondral bone at
a specific body joint locations.
7. The joint support and subchondral support system of claim 1,
wherein the contoured, porous plate may be inserted in at least two
locations of the subchondral bone as a modular or monobloc
insert.
8. The joint support and subchondral support system of claim 1,
wherein the inner surface, outer surface and peripheral surface
each have a geometry, which varies according to the exact anatomic
location being treated and specific geometry of lesion being
treated.
9. The joint support and subchondral support system of claim 1,
wherein at least one guide pin may be configured to break away from
the contoured, porous plate upon insertion of the plate within the
subchondral bone.
10. The joint support and subchondral support system of claim 1,
wherein the contoured, porous plate has a cross-sectional area or
from about 1 mm.sup.2 no about 100 cm.sup.2.
11. The joint support and subchondral support system of claim 1,
wherein the contoured, porous plate has a vertical dimension of
from about 1 mm to about 100 mm and a horizontal dimension of from
about 1 mm about 100 mm.
12. The joint support and subchondral support system or claim 1,
wherein the peripheral surface has a variable thickness of from
about 0.1 mm to about 5 cm.
13. The joint support and subchondral support system of claim 1,
wherein the insertion of the contoured, porous plate is peripheral
or tangential to a body joint surfaces.
14. The joint support and subchondral support system of claim 1,
wherein the contoured, porous plate has at least one active or
passive dampening element attached thereto.
15. The joint support and subchondral support system of claim 1,
wherein the contoured, porous plate is fabricated of a
biocompatible material selected from the group consisting of
metals, metal alloys, carbon fibers, foam metals, ceramics, ceramic
composites, elastomer composites, elastomer-carbon fiber
composites, chambered or fluid-filled materials, metal matrices,
injectable gels, injectable composites with fluid and sold
matrices, bone or bone-composite or allografts, crystal or
hydroxyapatite materials, plastics, polymers, bioabsorbable
composites, or composites/combinations of the above materials.
16. A joint support and subchondral support system for providing
structural and dampening support to damaged subchondral bone
adjacent to a body joint, comprising: an elongated plate having a
plurality of tapered strut elements of variable geometry and
thickness oriented in a vertical configuration for insertion into
the subchondral bone; the strut elements comprising a plurality of
superior struts formed on an upper portion of the plate and a
plurality of inferior struts formed on a lower portion of the
plate, wherein the plurality of inferior struts may bee configured
to be out of plane with the plurality of superior struts.
17. The joint support and subchondral support system of claim 16,
wherein the elongated plate may be inserted separately from the
plurality of strut elements within the subchondral bone as a
modular insert.
18. The joint support and subchondral support system of claim 16,
wherein the plurality of strut elements has a porosity of at least
one of micropores, scaffold-like pores, and fibrous matrix
material.
19. The joint support and subchondral support system of claim 16,
wherein the elongated plate may be releasably attached to the
plurality of strut elements with smoothly rounded joint elements at
each intersection of the strut elements and the elongated
plate.
20. The joint support and subchondral support system of claim 16,
wherein the plurality of strut elements may have a variable
orientation or geometry of at least one of sinusoidal, parallel,
radial, circular, curved, rectangular, trapezoidal, hexagonal,
octagonal, cross-hatching, and cross-elements.
21. The joint support and subchondral support system of claim 16,
wherein the plurality of the superior and inferior struts have a
width of from about 0.1 mm to about 10 mm and a height of from
about 0.5 mm to about 35 mm.
22. The Joint support and subchondral support system of claim 16,
wherein the plurality of superior struts has a primary bearing
element configured to be contoured such that the primary bearing
element is generally the same as the corresponding subchondral none
being treated.
23. The joint support and subchondral support system of claim 22,
wherein the primary bearing element includes a flared bearing
surface that is substantially wider than each of the plurality of
superior struts.
24. The joint support and subchondral support system of claim 23,
wherein the flared bearing surface has a width of from about 1.1 to
about 4.times. a width of each of the plurality of superior
struts.
25. The joint support and subchondral support system of claim 16,
wherein the plurality of superior struts may include at least one
secondary bearing element that connects the plurality of superior
struts to each other.
26. The joint support and subchondral support system of claim 25,
wherein the at least one secondary bearing element has a width of
from about 0.5 to about 5.times. a width of the superior strut.
27. The joint support and subchondral support system of claim 16,
wherein at least one guide hole or slot is located within the
elongated plate to aid insertion and placement of the plate and
plurality of strut elements over at least one corresponding guide
pin within the subchondral bone.
28. The joint support and subchondral support system of claim 16,
wherein the elongated plate and plurality of strut elements have at
least one active or passive dampening element attached thereto.
29. The joint support and subchondral support system of claim 16,
wherein the elongated plate and plurality of strut elements are
fabricated of a biocompatible material selected from the group
consisting of metals, metal alloys, carbon fibers, foam metals,
ceramics, ceramic composites, elastomer composites elastomer-carbon
fiber composites, chambered or fluid-filled materials, metal
matrices, injectable gels, injectable composites with fluid and
sold matrices, bone or bone-composite or allografts, crystal or
hydroxyapatite materials, plastics, polymers, bioabsorbable
composites, or composites/combinations of the above materials.
30. A joint support and subchondral support system for providing
structural and dampening support to damaged subchondral bone
adjacent to a body joint, comprising: a plurality of vertical
struts of variable geometry and thickness having a first end and a
second end, suitable for modular insertion within the subchondral
bone; the plurality of vertical struts further comprising a porous,
bearing surface that is contoured to fit the subchondral bone being
treated, wherein the porous, bearing surface includes a primary
bearing flare.
31. The joint support and subchondral support system of claim 30,
wherein the vertical struts may have a porosity comprised of
micropores, scaffold-like pores, or fibrous matrix material.
32. The joint support and subchondral support system of claim 30,
wherein the vertical struts may have a cross-sectional shape of at
least one of a triangle, thermometer-shape, trapezoid, flared
diamond-shape, oval, tapered with flared diamond-shape, and
rectangle.
33. The joint support and subchondral support system of claim 30,
wherein at least one of the plurality of vertical struts first end
and second end is tapered to assist in progressively dissipating
stress within the subchondral bone.
34. The joint support and subchondral support system of claim 30,
wherein the porous, bearing surface includes a secondary bearing
flare extending below the bearing surface.
35. The joint support and subchondral support system of claim 34,
wherein the secondary bearing flare is at least one of a horizontal
wing strut and dimple.
36. The joint support and subchondral support system of claim 30,
wherein the plurality of vertical struts are inserted in at least
one of a parallel and radial orientation within the subchondral
bone.
37. The joint support and subchondral support system of claim 30,
wherein at least one active or passive dampening element is
attached to the plurality of vertical struts.
38. A joint support and subchondral support system for providing
structural and dampening support to damaged subchondral bone
adjacent to a body joint, comprising: a primary bearing strut
element of variable geometry and thickness having a longitudinal
body and an inner edge and an outer edge, suitable for insertion
within the subchondral bone; the longitudinal body having a
porosity to allow vascularity, bridging bone, and other biological
elements to pass through; the inner edge having scalloping to
penetrate the subchondral bone during insertion; and the outer edge
having at least two grooves formed therein an inner surface of the
longitudinal body and contoured to fit the subchondral bone at the
treatment site.
39. The joint support and subchondral support system of claim 38,
wherein an inserter holder may be slidably disposed through the at
least two grooves at the outer edge on the inner surface of the
longitudinal body and extended past the inner edge during insertion
of the strut element within the subchondral bone.
40. The joint support and subchondral support system of claim 39,
wherein the inserter holder has a plurality of spikes at a distal
end that may be slidably disposed within the at least two grooves
at the outer edge on the inner surface of the longitudinal
body.
41. The joint support and subchondral support system of claim 40,
wherein the plurality of spikes extend past the inner edge create
channels in the subchondral bone whereby blood or marrow may access
the outer edge through the grooves or vascular channels.
42. The joint support and subchondral support system of claim 38,
wherein the geometric shape of the primary bearing strut element is
a circle.
43. The joint support and subchondral support system of claim 38,
wherein single or multiple geometric shapes of the primary bearing
strut elements may be configured to be joined to each other in
various patterns such that the geometric shapes may penetrate the
subchondral bone to be treated.
44. The joint support and subchondral support system of claim 43,
wherein the single or multiple geometric shapes configured to be
joined together include at least three connecting struts to form a
multiple concentric circle in which each circle of the primary
bearing strut element is connected to an adjacent circle by the
connecting struts.
45. The joint support and subchondral support system of claim 38,
wherein the primary bearing strut element has a diameter of from
about 1 mm to about 5 cm and a height/depth of from about 1 mm to
about 3 cm.
46. The joint support and subchondral support system of claim 38,
wherein inner edge and outer edge of the primary bearing strut
element is tapered.
47. The joint support and subchondral support system of claim 38,
wherein the longitudinal body includes a primary bearing flare.
48. The joint support and subchondral support system of claim 38,
wherein the longitudinal body includes a secondary flare extending
below the longitudinal body.
49. The Joint support and subchondral support system of claim 38,
wherein the secondary flare is at least one of a vertical,
double-tapered wing strut and obliquely extending arm.
50. The joint support and subchondral support system of claim 38,
wherein the porosity of the longitudinal body may be comprised of
micropores, scaffold-like pores, or a fibrous matrix material.
51. The joint support and subchondral support system of claim 38,
wherein the primary bearing strut element includes a concentric
taper from the outer edge to the inner edge.
52. The joint support and subchondral support system of claim 38,
wherein the primary bearing strut element may have a geometry in
the form of a multiple concentric circle, joined circles, hexagon,
octagon, or other non-euclidean shapes.
53. The joint support and subchondral support system of claim 38,
wherein a bearing surface cover may be attached to a periphery of
the outer edge to contain marrow contents entering through vascular
channels or exogenous substances injected through the cover.
54. The joint support and subchondral support system of claim 53,
wherein the bearing surface cover is fabricated from a thin, netted
or woven material or biologic/synthetic membrane.
55. The joint support and subchondral support system of claim 38,
wherein at least one active or passive dampening element is
attached to the primary bearing strut element.
56. The joint support and subchondral support system or claim 38,
wherein the primary bearing strut element is fabricated of a
biocompatible material selected from the group consisting of
metals, metal alloys, carbon fibers, foam metals, ceramics, ceramic
composites, elastomer composites, elastomer-carbon fiber
composites, chambered or fluid-filled materials, metal matrices,
injectable gels, injectable composites with fluid and sold
matrices, bone or bone-composite or allografts, crystal or
hydroxyapatite materials, plastics, polymers, bioabsorbable
composites, or composites/combinations of the above materials.
57. A joint support and subchondral support system for providing
structural and dampening support to damaged subchondral bone
adjacent to a body joint, comprising: a primary bearing strut
element of variable geometry and thickness having a longitudinal
body and an inner edge and an outer edge; the longitudinal body
having a porosity to allow vascularity, bridging bone, and other
biological elements to pass through; the outer edge having at least
two grooves formed therein an inner surface of the longitudinal
body and contoured to fit the subchondral bone at the treatment
site; a contoured, porous plate having a variable shaped inner
surface, outer surface, and peripheral surface of variable
thickness extending between the Inner surface and the outer
surface, suitable for insertion within the subchondral bone; the
inner surface, outer surface and peripheral surface each having a
concave portion and a convex portion; wherein the inner edge of the
primary bearing strut element is in direct communication with the
contoured porous plate within the subchondral bone being
treated.
58. The joint support and subchondral support system of claim 57,
wherein the primary bearing strut element has at least one active
or passive dampening element attached thereto.
59. The joint support and subchondral support system of claim 57,
wherein the contoured, porous plate has at least one active or
passive dampening element attached thereto.
Description
[0001] Cartilage disease has been previously addressed by various
means of replacing or substituting the damaged cartilage.
Microfracture or abrasionplasty is a form of irritating exposed
bone to create replacement fibrocartilage, but the resultant
material is inferior to native cartilage. Osteochondral transplant
replaces plugs of diseased cartilage and accompanying subchondral
bone with grafts from either the patient or human cadaver. Small
discrete lesions work well, but larger lesions, bipolar disease,
and diffuse disease are not well addressed. Chondrocyte
implantation harvests the patient's cartilage cells, grows them,
and re-implants them on the bony bed, and covers them with a
periosteal patch. Each of the aforementioned techniques work best
for small contained lesions, unipolar defects (i.e., one side of
joint), and primarily femoral condyle lesions. Less optimal results
occur with patellofemoral joint disease, and tibial sided
disease.
[0002] A further method of treating cartilage disease is to realign
the joint with an osteotomy. This relieves an overloaded
compartment, transferring stress to a less diseased compartment.
Success of this method involves avoiding non-union and other
complications, and requires prolonged non-weight bearing activity
and eight to twelve months to realize clinical benefits. Only
patients with mostly unicompartmental disease are candidates.
Osteotomy also complicates latter joint replacement.
[0003] Arthroscopy is used to treat other causes of pain from
arthritis, namely, loose bodies, loose or frayed cartilage,
meniscus tears, and synovitis. These are temporizing measures.
[0004] The end stage of cartilage disease is to perform total joint
reconstruction. This type of procedure presents a prolonged
recovery time and surgical risks. Because total joint prostheses
are fabricated of metal and plastic, revision surgery for worn-out
components is fraught with much higher complications than primary
surgery, and is inevitable if the patient lives much beyond ten
years.
[0005] Not much is known about the cause and progression of
arthritis. With current diagnostic techniques such as MRI and bone
scintigraphy, more has been elucidated about the disease process.
In particular, the subchondral bone plays an important role in the
initiation and progression of arthritis. Arthritis is a disease of
not just the cartilage, but the underlying subchondral bone as
well. Most of the clinical research to date is focused on cartilage
regeneration/replacement and not on the underlying bone health.
[0006] Traditionally, cartilage has been viewed to be avascular,
with diffusion of nutrients occurring from within the joint.
Studies have confirmed, however, that subchondral bone is a source
of vascular and nutritional support for cartilage. With age,
vascular and structural support from the subchondral bone
diminishes, allowing arthritic disease to progress. Namely, the
inability of the bone to adequately repair itself as increasing
damage occurs starts a cycle of further destruction, interfering
with cartilage vascular supply and structural support.
[0007] As cartilage wear occurs, the primary functions of
cartilage--to provide a low-friction bearing surface and to
transmit stresses to the underlying bone--are diminished. Bone is
most healthy when resisting compressive stresses. The shear
stresses from the joint are partially converted to compression and
tension via the architecture of the cartilage baseplate, the layer
between the cartilage and underlying bone is undulating. Further,
by virtue of the ultra low friction surface of cartilage on
cartilage (20.times. lower friction than ice on ice), shear
stresses are mostly converted to longitudinal. The subchondral bone
is the predominant shock absorber of joint stress. Via its
arch-like lattice-work of trabecular bone, stresses are transmitted
to the outer cortices and ultimately dissipated. Cartilage itself
does very little shock absorption secondary to its shear thickness
and mechanical properties.
[0008] Bone is the ultimate shock absorber, with fracture being the
endpoint of force attenuation. Trabecular microfractures have been
shown to occur in locations of bone stress in impulsively loaded
joints. Every joint has a physiologic envelope of function--when
this envelope of function is exceeded, the rate of damage exceeds
the rate of repair. As cartilage disease progresses, subchondral
bone is less able to dissipate the stress it encounters, i.e.,
shear-type stresses. The attempts of subchondral bone to heal and
remodel are seen as arthritis progresses--osteophyte formation,
subchondral sclerosis, cyst formation, and subchondral MRI-enhanced
changes, and increased signal on bone scintigraphy. Joint deformity
from these changes further increases joint reaction force.
Cartilage homeostasis is compromised--structural, vascular, neural,
and nutritional.
[0009] Clinical success of current cartilage surgery is limited as
it generally only works for small, unipolar (one-sided joint)
lesions of the femoral condyle. No current treatment exists for
bone edema or osteonecrosis of the knee.
[0010] It would be desirable to have a minimally invasive joint
support and subchondral support system that specifically addresses
the subchondral bone in arthritic disease process and progression,
and relieves the pain that results from diseased subchondral bone
and the spectrum of symptoms that result from arthritis, including
pain, stiffness, swelling, and discomfort. It would be further
desirable to have a joint support and subchondral support system
that provides as follows: (1) a treatment specifically for bone
edema and bone bruises and osteonecrosis that has previously not
existed; (2) structural scaffolding to assist in the reparative
processes of diseased bone next to joints; (3) shock absorbing
enhancement to subchondral bone; (4) compressive, tensile, and
especially shear stress attenuation enhancement to subchondral
bone; (5) a means to prevent further joint deformity from
subchondral bone remodeling such as osteophyte formation; (6)
assistance in the healing of or prevention of further destruction
of overlying cartilage by maintaining and allowing vascularity and
nutritional support from subchondral bone; (7) assistance in the
healing of or prevention of further destruction of overlying
cartilage by providing an adequate structural base; (8) a minimally
invasive alternative to total joint reconstruction that also does
not preclude or further complicate joint reconstruction; (9) a
treatment for subchondral bone disease in its role in arthritis and
delay or halt further progression; (10) an implant for arthritis
that is minimally subject to loosening or wear, as it is integral
to the trabecular framework it supports; (11) an alternative for
tibial sided, patellofemoral, and bipolar disease (tibial-femoral)
that is relatively easy to perform, as an adjunct to arthroscopy,
and as an outpatient procedure with minimal downtime for the
patient; (12) a treatment for arthritis that allows higher lever of
activity than that allowed after joint resurfacing or replacement;
(13) a cost effective alternative to joint replacement with less
issues about the need for revision and surgical morbidity,
especially in countries with less medical resources; and (14) a
treatment option in veterinary medicine, specifically in equine
arthroses and arthritides.
SUMMARY OF THE INVENTION
[0011] The present invention provides a joint support and
subchondral support system or device for the treatment of damaged
subchondral bone in arthritic disease process and progression. The
present invention is described herein for the human knee joint, but
the device may apply to other joints and species. In a first
aspect, the present invention includes a contoured, porous plate
having a variable shaped inner surface, outer surface, and
peripheral surface of variable thickness extending between the
inner surface and the outer surface, suitable for insertion within
the subchondral bone. The inner surface, outer surface and
peripheral surface each have a concave portion and a convex
portion. The geometry of the inner surface, outer surface, and
peripheral surface may vary depending on the exact anatomic
location being treated (i.e., proximal tibia versus femoral
trochlea) and the specific geometry of the lesion being treated.
One to multiple guide pin holes or slots are located within the
device to aid insertion. The guide pin(s) are inserted into the
anatomic site initially with the device inserted over the pin(s)
via the holes or slots; the excess pin(s) may break away or be
removed after device is inserted within the subchondral bone.
[0012] The porosity of the contoured plate is within a range of
from about 50 microns to about 20 mm. The degree of porosity of the
contoured plate can be microporous, scaffold-like pores, or fibrous
matrix material. The contoured plate includes a plurality of
surface dimpling thereon having a radius of from about 50 microns
to about 3 mm. The contoured plate further includes a plurality of
undersurface pimples thereon having a radius of from about 50
microns to about 3 mm.
[0013] The contoured, porous plate is configured to fit flush with
at least one contour of the corresponding subchondral bone at the
specific body location to be treated, or it may be of reverse,
neutral or complex polarity. The contoured plate may be inserted in
at least two locations of the subchondral bone as a modular or
monobloc insert. At least two contoured, porous plates may be
placed anterior and posterior to each other within the subchondral
bone. The contoured, porous plate has a cross-sectional area of
from about 1 mm.sup.2 to about 100 cm.sup.2. The peripheral surface
has a variable thickness of from about 0.1 mm to about 5 cm. The
central area of the plate may be of a thinner dimension, with a
reverse taper to increase thickness peripherally.
[0014] The contoured, porous plate includes at least one active or
passive dampening element. The materials which comprise the joint
support and subchondral support system are dampening, thereby
enhancing the trabecular bone's ability to withstand shock and
shear stress. The joint support and subchondral support system is
fabricated of a biocompatible material, such as metals, metal
alloys, carbon fibers, foam metals, ceramics, ceramic composites,
elastomer composites, elastomer-carbon fiber composites, chambered
or fluid-filled materials, metal matrices, injectable gels,
injectable composites with fluid and solid matrices, bone or
bone-composite or allografts, crystal or hydroxyapatite materials,
plastics (i.e., PEEK), polymers, bioabsorbable composites (i.e.,
TCP/PLLA), or combinations of the above materials.
[0015] In another aspect of the present invention, a joint support
system for providing structural and dampening support to damaged
subchondral bone adjacent to a body joint includes an elongated
plate having a plurality of tapered strut elements of variable
geometry and thickness oriented in a vertical configuration for
insertion into the subchondral bone. The strut elements include a
plurality of superior struts formed on an upper portion of the
plate and a plurality of inferior struts formed on a lower portion
of the plate, wherein the plurality of inferior struts may be
configured to be out of plane with the plurality of superior
struts.
[0016] The elongated plate may be inserted separately from the
plurality of strut elements within the subchondral bone as a
modular insert. The plurality of strut elements has a porosity of
at least one of micropores, scaffold-like pores, and fibrous matrix
material. The elongated plate may be releasably attached to the
plurality of strut elements with smoothly rounded joint elements at
each intersection of the strut elements and plate.
[0017] The plurality of strut elements has a geometry of at least
one of sinusoidal, parallel, radial, circular, curved, rectangular,
trapezoidal, hexagonal, ocatagonal, cross-hatching, and
cross-elements. The plurality of the superior and inferior struts
have a width of from about 0.1 mm to about 10 mm and a height of
from about 0.5 mm to about 35 mm.
[0018] The plurality of superior struts has a primary bearing
element configured to be contoured such that the primary bearing
element is generally the same as the corresponding subchondral bone
being treated. The primary bearing element may include a flared
bearing surface that is substantially wider than each of the
plurality of superior struts. The flared bearing surface has a
width of from about 1.1 to about 4.times. a width of each of the
plurality of superior struts. The plurality of superior struts may
include at least one secondary bearing element that connects the
plurality of superior struts to each other. At least one secondary
bearing element has a width of from about 0.5 to about 5.times. the
width of the superior strut. The primary and secondary bearing
elements have surface material properties, which allow an ultra-low
coefficient of friction.
[0019] One to multiple guide pin holes or slots are located within
the device to aid insertion. The guide pin(s) are inserted into the
anatomic site initially with the device inserted over the pin(s)
via the holes or slots; the excess pin(s) may break away or be
removed after device is inserted within the subchondral bone.
[0020] The elongated plate and plurality of strut elements have at
least one active or passive dampening element. The elongated plate
and plurality of strut elements are fabricated of a biocompatible
material of the same type as set forth in the prior embodiment.
[0021] In a further aspect of the present invention, a joint
support and subchondral support system for providing structural and
dampening support to damaged subchondral bone adjacent to a body
joint, includes a plurality of vertical struts of variable geometry
and thickness having a first end and a second end, suitable for
modular insertion within the subchondral bone. The plurality of
vertical struts further include a bearing surface contoured to fit
the subchondral bone being treated, wherein the bearing surface
includes a primary bearing flare.
[0022] The device may have a porosity comprised of micropores,
scaffold-like pores, or fibrous matrix material. The plurality of
separate vertical struts may have various cross-sectional shapes
such as triangular (both polarities), smooth thermometer-like,
trapezoid, flared diamond-shaped, oval, tapered with
flared-diamond, and rectangular. At least one of the plurality of
vertical struts first end and second end is tapered. The bearing
surface includes a secondary bearing flare extending below the
bearing surface. The secondary bearing flare is at least one of a
horizontal wing strut and dimple.
[0023] The plurality of vertical struts are inserted in either a
parallel or radial orientation within the subchondral bone. The
plurality of vertical struts have at least one active or passive
dampening element and are fabricated of a biocompatible material of
the same type as set forth in the prior embodiments.
[0024] In still another aspect of the present invention, a joint
support and subchondral support system for providing structural and
dampening support to damaged subchondral bone adjacent to a body
joint includes a primary bearing strut element of variable geometry
and thickness having a longitudinal body and an inner edge and an
outer edge, suitable for insertion within the subchondral bone. The
longitudinal body has a porosity to allow vascularity, bridging
bone, and other biological elements to pass through. The inner edge
is scalloped to penetrate the subchondral bone during insertion.
The outer edge has at least two grooves formed therein an inner
surface of the longitudinal body. An inserter holder may be
slidably disposed through at least two grooves at the outer edge on
the inner surface of the longitudinal body and extended past the
inner edge during insertion of the strut element within the
subchondral bone. The basic shape of the primary bearing strut
element is a circle. The primary bearing strut elements may be
configured to be joined to each other in the form of a geometric
shape such as a multiple concentric circle, joined circles,
hexagon, octagon, and other non-linear, non-euclidean shapes, such
as a hexagon with smooth edges.
[0025] Single or multiple geometric shapes may be configured to be
joined to each other in various patterns such that the geometric
shapes may penetrate the subchondral bone to be treated. The
plurality of strut elements configured to be joined together
include at least three connecting struts to form a multiple
concentric circle in which each circle of joined together primary
bearing strut elements is connected to an adjacent circle by the
connecting struts. The primary bearing strut elements configured to
be joined together in a geometric shape each have a diameter of
from about 1 mm to about 5 cm and a height/depth of from about 1 mm
to about 3 cm.
[0026] A bearing surface cover may be attached to the periphery of
the outer edge of the primary bearing strut element to contain
marrow contents entering the treatment site via the vascular
channels or exogenous substances injected through the cover. The
bearing surface cover may be fabricated of either a thin netted or
woven material or a biologic/synthetic membrane.
[0027] The primary bearing strut element inner edge and outer edge
is tapered from the outer edge to the inner edge. The bearing
surface includes a primary bearing flare and a secondary flare
extending below the primary bearing strut element. The secondary
flare can be in the form of either a vertical double tapered wing
strut or obliquely extending arm.
[0028] The primary bearing strut element has at least one active or
passive dampening element attached thereto and is fabricated of a
biocompatible material of the same type as set forth in the prior
embodiments.
[0029] In yet another aspect of the present invention, a joint
support and subchondral support system for providing structural and
dampening support to damaged subchondral bone adjacent to a body
joint includes a primary bearing strut element of variable geometry
and thickness having a longitudinal body and an inner edge and an
outer edge. The longitudinal body has porosity to allow
vascularity, bridging bone, and other biological elements to pass
through. The outer edge has at least two grooves formed therein an
inner surface of the longitudinal body and contoured to fit the
subchondral bone at the treatment site. A contoured, porous plate
having a variable shaped inner surface, outer surface, and
peripheral surface of variable thickness extending between the
inner surface and the outer surface, suitable for insertion within
the subchondral bone. The inner surface, outer surface, and
peripheral surface, each have a concave portion and a convex
portion. The inner edge of the primary bearing strut element is in
direct communication with the contoured porous plate within the
subchondral bone being treated.
[0030] These and other features and advantages of this invention
will become further apparent from the detailed description and
accompanying figures that follow. In the figures and description,
numerals indicate the various features of the disclosure, like
numerals referring to like features throughout both the drawings
and the description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a perspective view of an embodiment of a joint
support and subchondral support system according to the present
invention.
[0032] FIGS. 2A-2C illustrate the various degrees of porosity of
the contoured, porous plate of the embodiment of FIG. 1.
[0033] FIGS. 3A-3B are perspective views of the dampening element
of the joint support and subchondral support system according to
the present invention.
[0034] FIGS. 4A-4E illustrate the placement of the device of FIG. 1
in subchondral bone of the tibial plateau.
[0035] FIG. 5A illustrates the placement of the device of FIG. 1 in
subchondral bone of the femoral condyle and the tibial plateau as a
monobloc insert.
[0036] FIG. 5B is a top plan view of the placement of the device of
FIG. 1 in subchondral bone of the tibial plateau as both a modular
insert and a monobloc insert.
[0037] FIG. 5C is a front perspective view of the placement of the
device of FIG. 1 in subchondral bone of the femoral trochlea.
[0038] FIG. 5D is a front perspective view of the placement of the
device of FIG. 1 in subchondral bone of the patella.
[0039] FIG. 6 is a perspective view of another embodiment of the
joint support and subchondral support system according to the
present invention.
[0040] FIGS. 7A-7D illustrate the placement of the device of FIG. 6
in subchondral bone of a knee joint.
[0041] FIG. 8 illustrates the placement of the elongated plate
separately from the plurality of strut elements within the
subchondral bone of the knee joint as a modular insert.
[0042] FIG. 9 is an enlarged perspective view of the elongated
plate releasably attached to the plurality of strut elements of
FIG. 6.
[0043] FIGS. 10A-10C illustrate the various degrees of porosity of
the plurality of strut elements of the embodiment of FIG. 6.
[0044] FIGS. 11A-11H illustrate a top view of several variable
orientations or geometries of the plurality of strut elements of
the embodiment of FIG. 6.
[0045] FIG. 12A illustrates an enlarged perspective view of the
plurality of superior struts of the embodiment of FIG. 6.
[0046] FIGS. 12B-12D illustrate various configurations of the
flared bearing surface of the embodiment of FIG. 6.
[0047] FIG. 12E is a perspective view of the secondary bearing
element of the embodiment of FIG. 6.
[0048] FIG. 13A is a perspective view of the dampening element as a
long cylinder housed in the periphery of the device of FIG. 6.
[0049] FIG. 13B is a perspective view of the dampening element as
individual spheres embedded in the periphery of the device of FIG.
6.
[0050] FIG. 14A is a perspective view of a further embodiment of
the joint support and subchondral support system according to the
present invention.
[0051] FIG. 14B illustrates the various configurations of the
primary bearing flare of the device of FIG. 14A.
[0052] FIG. 15 illustrates the placement of the device of FIG. 14A
in subchondral bone of a knee joint in a parallel orientation.
[0053] FIGS. 16A-16C illustrate the various degrees of porosity of
the device of FIG. 14A.
[0054] FIGS. 17A-17G illustrate an enlarged perspective view of
each of the different cross-sectional shapes of the device of FIG.
14A.
[0055] FIG. 18 illustrates the placement of the device of FIG. 14A
in subchondral bone of a knee joint in a radial versus parallel
orientation.
[0056] FIG. 19 is an enlarged perspective view of the porous,
bearing surface of the embodiment of FIG. 14A with associated
secondary flares.
[0057] FIG. 20A is a cut-away view of another embodiment of the
joint support and subchondral support system according to the
present invention.
[0058] FIG. 20B is a perspective view of the embodiment of FIG. 20A
illustrated as a complete circle.
[0059] FIGS. 21A-21C illustrate the various degrees of porosity of
the device of FIG. 20.
[0060] FIGS. 22A-22B illustrate the outer edge of the device of
FIG. 20 having concave and convex curvatures.
[0061] FIG. 22C illustrates the concentric taper of the primary
bearing strut element of the embodiment of FIG. 20.
[0062] FIG. 23 illustrates the placement of the device of FIG. 20
in subchondral bone of a knee joint by monobloc via antegrade
insertion.
[0063] FIGS. 24A-24C illustrate the varying levels of the depth of
penetration of the device of FIG. 20.
[0064] FIG. 25A is an enlarged perspective view of an insertion
holder used in conjunction with the embodiment of FIG. 20 during
insertion of the device within the subchondral bone.
[0065] FIG. 25B illustrates the placement of the insertion holder
spikes within each of the grooves of the embodiment of FIG. 20
during insertion of the device within the subchondral bone.
[0066] FIG. 26 illustrates a perspective view of the bearing
surface cover in accordance with the embodiment of FIG. 20.
[0067] FIGS. 27A-27F illustrate the various geometric shapes that
can be formed by the primary bearing strut elements of the
embodiment of FIG. 20.
[0068] FIG. 28 illustrates the placement of the device of FIG. 18
in subchondral bone of a knee joint with multiple devices joined to
each other to form various patterns.
[0069] FIG. 29A is a cut-away view of the embodiment of FIG. 20
with a primary bearing flare.
[0070] FIG. 29B is a perspective view of the embodiment of FIG. 20
with a secondary flare.
[0071] FIG. 30 is a perspective view of a further embodiment of the
joint support and subchondral system according to the present
invention.
[0072] FIG. 31 illustrates the placement of the device of FIG. 30
in subchondral bone of a knee joint.
[0073] FIG. 32 is a perspective view of the placement of the joint
support and subchondral support system of each of the embodiments
in subchondral bone of a knee joint.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0074] The joint support and subchondral support system or device
10 of the present invention is generally illustrated in FIG. 1. It
is contemplated by the present invention that the joint support and
subchondral support system is not a substitute for partial or total
joint replacement, but may delay the need for joint replacement in
active individuals with moderate osteoarthritis and/or arthroses.
By sustaining subchondral bone homeostases, further joint deformity
and disease progression may be delayed and/or avoided. The joint
support and subchondral support system in accordance with the
present invention enhances and reinforces the cartilage-bone
complex in the presence of diseased cartilage or a cartilage
defect. It treats the bony side of the equation by mechanical
absorption of shear and compressive stresses that threaten
cartilage-bone homeostasis.
[0075] A number of advantages of the joint support and subchondral
support system in accordance with the present invention are evident
as follows: (1) the basic structure and mechanics of the system are
applicable to many parts of the joint, as any area with cartilage
disease has an adjoining subchondral component; (2) minimal
modifications in manufacturing are necessary to apply this system
to multiple areas, namely, the contour of the porous, plate closest
to the joint; (3) the device may be inserted with minimal soft
tissue dissection and minimal to no violation of the joint capsule
if done in retrograde or side-slot insertion methods; (4) antegrade
devices also may be inserted with a minimal arthrotomy; for diffuse
lesions with long anterior-posterior dimensions, two devices may be
placed anterior and posterior to each other through the same small
arthrotomy; (5) the system is inherently stable, as it occupies
little space within the bone and is a joint scaffolding, not a
replacement; and (6) the materials that comprise the system are
dampening, thereby enhancing the trabecular bone's ability to
withstand shock and shear stress.
[0076] The joint support and subchondral support system 10 includes
a contoured, porous plate 12 having a variable shaped inner surface
14, outer surface 16, and peripheral surface 18 of variable
thickness extending between the inner surface 14 and the outer
surface 16, suitable for insertion within the subchondral bone 20.
The contoured, porous plate 12 inner surface 14, outer surface 16,
and peripheral surface 18 may be kidney-shaped, oval-shaped, or
otherwise so shaped to fit within the subchondral bone 20 at the
desired anatomic site. The inner surface 14, outer surface 16, and
peripheral surface 18 each have a respective concave portion 14A,
16A, 18A, and a respective convex portion 14B, 16B, 18B. The inner
surface 14 of the contoured, porous plate 12 is closest to the
joint 22 and the first part of the system 10 that encounters
stress. The inner surface 14 is configured to fit flush with the
respective geometries of the tibial and femoral sides of the joint
22, and may be convex, concave, or complex to mirror the particular
anatomic location. The outer surface 16 will mirror the geometry of
the inner surface 14. The geometry of the inner surface 14, outer
surface 16, and peripheral surface 18, may vary depending on the
exact anatomic location being treated (i.e., proximal tibia versus
femoral trochlea) and the specific geometry of the lesion being
treated.
[0077] The contours 32 of the porous plate 12 may be configured to
match the chondral/subchondral curvature and anatomy of the
specific joint 22 location. Alternatively, the contours 32 may not
be configured to match the chondral/subchondral 20 curvature and
anatomy of the specific joint 22 location such that the contours 32
are neutral or assume a reverse or varied polarity.
[0078] The contoured, porous plate 12 has a porosity 24 to allow
vascularity and other biologic elements from the host to pass
through the contoured, porous plate 12. The porosity 24 of the
contoured, porous plate 12 is within a range of from about 50
microns to about 20 mm. As shown in FIGS. 2A-2C, the porosity 24 of
the contoured, porous plate 12 may be comprised of micropores 26,
scaffold-like pores 28, or fibrous matrix material 30.
[0079] Referring further to FIG. 1, the contoured, porous plate 12
includes a plurality of surface dimpling 34, which increases the
surface area for stress absorption and converts as much shear
stress to compressive or tensile stress, as the cartilage baseplate
of the joint 22 has similar features. The surface dimpling 34 has a
radius of from about 50 microns to about 3 mm. The contoured,
porous plate 12 may further include a plurality of undersurface
pimples 36, which increase the surface area below the contoured,
porous plate 12 to spread the load. The undersurface pimples 36
have a radius of from about 50 microns to about 3 mm.
[0080] The dimensions of the system or device 10 generally depend
on the size of the lesion being treated. Typically, two or more
devices 10 will be deployed per location for diffuse disease and
one device for smaller lesions. The vertical dimension ranges from
about 1 mm to about 100 mm and the horizontal dimension ranges from
about 1 mm to about 100 mm. The contoured, porous plate 12 has a
cross-sectional area of from about 1 mm.sup.2 to about 100
cm.sup.2. The peripheral surface 18 of the contoured, porous plate
12 has a variable thickness of from about 0.1 mm to about 5 cm. At
least one active or passive dampening element 38 is attached to the
contoured, porous plate 12. A dampening element, such as a
piezoelectric device, converts active mechanical energy to heat or
electric, thereby dissipating and dampening the shock. A passive
dampening element 38 may be made of silicone or other
shock-absorbing material. Either active or passive dampening
element 38 may be incorporated into plate as illustrated in FIGS.
3A-3B. FIG. 3A illustrates the dampening element 38 as a long
cylinder housed in the periphery of the device 10. FIG. 3B
illustrates the dampening element 38 as individual spheres embedded
in the periphery of device 10. The dampening element 38 may also be
inherent within the material properties of the device, and not a
separate component, i.e., silicone-impregnated porous metal
matrix.
[0081] Referring to FIG. 4, at least one to multiple guide pin
holes or slots 40 are located within device 10 to aid insertion
within the subchondral bone 20. The guide pin(s) 42 are inserted
into the anatomic site initially (FIG. 4A) with device 10 inserted
over the guide pin(s) 42 (FIG. 4B). A bone cutter/dilator 44 is
inserted over the guide pin(s) 42 to create an entry opening and
slot 45 for device 10 (FIG. 4C). The bone cutter or dilator 44 is
smaller in dimension than device 10, thereby allowing a press-fit
fixation. The device 10 is inserted over the guide pin(s) 42 via
the holes or slots 40 (FIG. 4D). The excess guide pin(s) 42 may
break away or be removed after device 10 is inserted within the
subchondral bone 20. One guide pin 42 may be used initially as
device 10 is allowed small amounts of swiveling to more exactly fit
the contours of the subchondral baseplate 20. Placement of the
guide pin 42 into the subchondral defect 20 may be accomplished by
either fluoroscopic guidance, CT guidance, computer navigation
guidance, or direct guidance. In one embodiment, the guide pin 42
may be configured to break away from the contoured, porous plate 12
upon insertion of the device 10 within the subchondral bone 20.
[0082] The operation of the device 10 for the femur involves
placing a guide pin 42 into the center of the subchondral defect 20
from within the joint 22. This is followed by a bone cutter or
dilator 44 to prepare the bone. The device 10 is then inserted over
the guide pin 42 and positioned flush with the subchondral bone 20
with a tamp. The insertion of the device 10 is peripheral or
tangential to the joint surface (FIG. 4E).
[0083] FIG. 5A illustrates the placement of the joint support and
subchondral support system or device 10 in subchondral bone 20 of
the femoral condyle and the tibial plateau as a monobloc 48 insert.
FIG. 5B is a top plan view of the placement of the device 10 in
subchondral bone 20 of the tibial plateau as both a modular 46 and
a monobloc 48 insert. As shown in FIG. 5B, the contoured, porous
plate 12 may be inserted in at least two different locations of the
subchondral bone 20 as a modular 46 or monobloc 48 insert. FIG. 5C
is a front perspective view of the placement of the device 10 in
subchondral bone 20 of the femoral trochlea. FIG. 5D is a front
perspective view of the placement of the device 10 in subchondral
bone 20 of the patella.
[0084] The joint support and subchondral support system 10 of the
present invention may be fabricated from virtually any
biocompatible material, including, but not limited to, metals,
metal alloys, carbon fibers, foam metals, ceramics, ceramic
composites, elastomer composites, elastomer-carbon fiber
composites, chambered or fluid-filled materials, metal matrices,
injectable gels, injectable composites with fluid and sold
matrices, bone or bone-composite or allografts, crystal or
hydroxyapatite materials, plastics (i.e., PEEK), polymers,
bioabsorbable composites (i.e., TCP/PLLA), or
composites/combinations of the above materials. The preferred
materials for the system 10 have inherent elastic or shock
absorbing properties.
[0085] In another embodiment as shown in FIG. 6, the joint support
and subchondral support system or device 50 includes an elongated
plate 52 having a plurality of tapered strut elements 54 of
variable geometry and thickness oriented in a vertical
configuration for insertion into the subchondral bone 20. The strut
elements 54 include a plurality of superior struts 56 formed on an
upper portion 58 of the plate 52 and a plurality of inferior struts
60 formed on a lower portion 62 of the plate 52. The plurality of
inferior struts 60 may be configured to be out of plane with the
plurality of superior struts 56. There may be single to multiple
superior or inferior struts depending on the size of pathologic
lesion being treated.
[0086] FIG. 7A illustrates the placement of the joint support and
subchondral support system 50 in subchondral bone 20 of the femoral
condyle and tibial plateau and patella in accordance with the
present invention.
[0087] It is contemplated by the present invention that the
elongated plate 52 may be inserted separately from the plurality of
strut elements 54 within the subchondral bone 20 as a modular
insert 64 shown in FIG. 8.
[0088] The elongated plate 52 serves as a secondary bearing element
and dissipates stresses centripetally and absorbs stress
inherently. The elongated plate 52 thickness and material
properties may vary to enable stress transmission outward. The
elongated plate 52 prevents subsidence of the structural support
system 50. The dimension of the elongated plate 52 is dependant on
the size of lesion being treated. The vertical dimension ranges
from about 1 mm to about 100 mm and the horizontal dimension ranges
from about 1 mm to about 100 mm. The elongated plate 52 has a
cross-sectional area of from about 1 mm.sup.2 to about 100
cm.sup.2.
[0089] In one embodiment of FIG. 9, the elongated plate 52 is shown
releasably attached to the plurality of strut elements 54 with
smoothly rounded joint elements 66 at each intersection of the
strut elements 54 and the elongated plate 52. The plurality of
superior 56 and inferior 60 struts have a width of from about 0.1
mm to about 10 mm and a height of from about 0.5 mm to about 35
mm.
[0090] The plurality of superior struts 56 serves to accept the
load from the adjoining joint 22. The level of penetration of the
superior struts 56 within the subchondral bone 20 includes as
follows: the superior struts 56 may stop short or come up to the
cartilage base plate, may penetrate the cartilage base plate and
reside in the lower cartilage layer, or may come flush to the
native bearing cartilage surface. The plurality of inferior struts
60 reinforces the structural integrity of the elongated plate 52
and enables centripetal transmission/dissipation of forces to
underlying and surrounding structures (i.e., bone or soft
tissue).
[0091] As shown in FIGS. 10A-10C, the plurality of strut elements
54 may be fabricated to have a porosity comprised of micropores 68,
scaffold-like pores 70, or fibrous matrix material 72. The porosity
of the plurality of strut elements is within a range of from about
50 microns to about 20 mm.
[0092] The plurality of strut elements 54 may have a variable
orientation or geometry such as sinusoidal 74 (FIG. 11A), parallel
76 (FIG. 11B), radial 78 (FIG. 11C), circular 80 (FIG. 11D), curved
(FIG. 11E), geometric-rectangular 82, trapezoidal 84, hexagonal 86,
octagonal 88 (FIG. 11F), cross-hatching or cross-elements 90 (FIG.
11G), or single columns 91 (FIG. 11H).
[0093] FIG. 12A illustrates an enlarged perspective view of the
plurality of superior struts 56 of the joint support and
subchondral support system 50 of FIG. 6. The plurality of superior
struts 56 have a primary bearing element 92 configured to be
contoured such that the primary bearing element 92 is generally the
same as the corresponding subchondral bone 20 being treated. The
primary bearing element 92 has an ultra-low coefficient of friction
surface that is polished or fabricated of a biocompatible material.
The primary bearing element 92 includes a flared bearing surface 94
that is substantially wider than each of the plurality of superior
struts 56. The flared bearing surface 94 may be configured to
assume a variety of shapes such as circular (FIG. 12B), flat (FIG.
12C), mushroom-like (FIG. 12D), and the like. The flared bearing
surface 94 has a width of from about 1.1 to about 4.times. a width
of each of the plurality of superior struts 56. The plurality of
superior struts 56 may include at least one secondary bearing
element 96 (FIG. 12E) that connects the plurality of superior
struts 56 to each other. The secondary bearing element 96 has a
width of from about 0.5 to about 5.times. the width of the superior
strut 56.
[0094] A guide pin hole or slot 98 is positioned within the
elongated plate 52 oriented longitudinally for insertion and
placement of the plate 52 and plurality of strut elements 54 over
at least one corresponding guide pin 102 within the subchondral
bone 20 (FIGS. 7B-7D). At least one to multiple guide pin holes or
slots 98 are located within device 50 to aid insertion within the
subchondral bone 20. The guide pin(s) 102 is inserted into the
anatomic site initially (FIG. 7C). A bone cutter/dilator 100 is
inserted over the guide pin(s) 102 to create an entry opening and
slot 98 for device 50 (FIG. 7D). The bone cutter/dilator 100 is
smaller in dimension than device 50, thereby allowing a press-fit
fixation. The device 50 is inserted over the guide pin(s) 102 via
the guide pin holes or slots 98 (FIG. 7D). The excess guide pin(s)
102 may break away or be removed after device 50 is inserted within
the subchondral bone 20. Placement of the guide pin 102 into the
subchondral defect 20 may be accomplished by either fluoroscopic
guidance, CT guidance, computer navigation guidance, or direct
guidance. In one embodiment, the guide pin 102 may be configured to
break away from the elongated plate 52 upon insertion of the device
50 within the subchondral bone 20.
[0095] Referring further to FIG. 7, the operation of the device 50
for the femur involves placing a guide pin 102 into the center of
the subchondral defect 20 from within the joint 22. This is
followed by a bone cutter/dilator 100 to prepare the bone. The
device 50 is then inserted over the guide pin 102 and positioned
flush with the subchondral bone 20 with a tamp. The insertion of
the device 50 is peripheral or tangential to the joint surface
(FIG. 7).
[0096] At least one active or passive dampening element 104 is
attached to the elongated plate 52 and plurality of strut elements
54 (FIG. 13). An active dampening element, such as a piezoelectric
device, converts active mechanical energy to heat or electric,
thereby dissipating and dampening the shock. FIG. 13A illustrates
the dampening element 104 as a long cylinder housed in the
periphery of the device 50. FIG. 13B illustrates the dampening
element 104 as individual spheres embedded in the periphery of the
device 50. A passive dampening element may be made of silicone or
other shock-absorbing material. Either active or passive dampening
element 104 may be incorporated into plate 52 as illustrated in
FIGS. 13A-13B. The dampening element may also be inherent within
the material properties of the device 50, and not a separate
component, i.e., silicone-impregnated porous metal matrix.
[0097] The joint support and subchondral support system 50 of the
present invention may be fabricated from virtually any
biocompatible material, including, but not limited to, metals,
metal alloys, carbon fibers, foam metals, ceramics, ceramic
composites, elastomer composites, elastomer-carbon fiber
composites, chambered or fluid-filled materials, metal matrices,
injectable gels, injectable composites with fluid and sold
matrices, bone or bone-composite or allografts, crystal or
hydroxyapatite materials, plastics (i.e., PEEK), polymers,
bioabsorbable composites (i.e., TCP/PLLA), or
combinations/composites of the above materials. The preferred
materials for the system 50 have inherent elastic or shock
absorbing properties.
[0098] In a further embodiment as shown in FIG. 14A, the joint
support and subchondral support system 106 includes a plurality of
separate vertical struts 108 of variable geometry and thickness
having a first end 110 and a second end 112, suitable for modular
insertion 114 within the subchondral bone 20. At least one of the
plurality of vertical struts first end 110 and second end 112 is
tapered to assist in progressively dissipating stress. The
plurality of vertical struts 108 further include a porous, bearing
surface 116 contoured to fit the subchondral bone 20 being treated.
The porous, bearing surface 116 is configured to include a primary
bearing flare 118 of various configurations (FIG. 14B). The primary
bearing flare 118 prevents subsidence of the joint support and
subchondral support system 106.
[0099] FIG. 15 illustrates the joint support and subchondral
support system 106 in subchondral bone 20 of the femoral condyle
and tibial plateau in accordance with the present invention.
[0100] As shown in FIGS. 16A-16C, the device 106 may have a
porosity comprised of micropores 118, scaffold-like pores 120, or
fibrous matrix material 122. The porosity of the device 106 is
within a range of from about 50 microns to about 20 mm.
[0101] FIGS. 17A-17G illustrate an enlarged perspective view of the
different cross-sectional shapes of the strut device 108, such as a
triangular (both polarities) (FIG. 17A), smooth thermometer-like
(FIG. 17B), trapezoid (FIG. 17C), flared diamond-shaped (FIG. 17D),
oval (FIG. 17E), complex (tapered with flared-diamond) (FIG. 17F),
and rectangular (FIG. 17G).
[0102] The plurality of vertical struts 108 can be inserted in
either a parallel orientation 140 (FIGS. 15 and 18) or a radial
orientation 142 (FIG. 18) within the subchondral bone 20. Radial
orientation may enable centripetal load dissipation within the
subchondral bone. The top-down geometry of the struts may be curved
108A, straight 108B, or sinusoidal 108C as shown in FIG. 18.
[0103] The embodiment of FIG. 19 illustrates an enlarged
perspective view of the porous, bearing surface 116 having a
secondary bearing flare 144 extending below the bearing surface
116. The secondary bearing flare 144 distributes the load
horizontally, along the vertical length of the plurality of
vertical struts 108. The secondary bearing flare 144 can be in the
form of either a horizontal wing strut 146 or dimple 148. The
dimple 148 can be asymmetric in shape in which it is wider towards
the joint.
[0104] It is contemplated by the present invention that the
plurality of vertical struts 108 are implanted within the
subchondral bone 20 via side slot insertion as shown in FIG.
15.
[0105] Referring further to FIG. 19, at least one active or passive
dampening element 150 is attached to the plurality of vertical
struts 108. The dampening element may be within the main strut body
150A or housed within the secondary bearing flare 150B. A dampening
element, such as a piezoelectric device, converts active mechanical
energy to heat or electric, thereby dissipating and dampening the
shock. The dampening element 150 may also be inherent in the
material properties of the device 106, i.e., silicone-injected
porous metal matrix.
[0106] The joint support and subchondral support system 106 of the
present invention may be fabricated from virtually any
biocompatible material, including, but not limited to, metals,
metal alloys, carbon fibers, foam metals, ceramics, ceramic
composites, elastomer composites, elastomer-carbon fiber
composites, chambered or fluid-filled materials, metal matrices,
injectable gels, injectable composites with fluid and sold
matrices, bone or bone-composite or allografts, crystal or
hydroxyapatite materials, plastics (i.e., PEEK), polymers,
bioabsorbable composites (i.e., TCP/PLLA), or
combinations/composites of the above materials. The preferred
materials for the system 106 have inherent elastic or shock
absorbing properties.
[0107] In still a further embodiment of FIG. 20, the joint support
and subchondral support system 150 includes a primary bearing strut
element 152 of variable geometry and thickness having a
longitudinal body 154 and an inner edge 156 and an outer edge 158,
suitable for insertion within the subchondral bone 20. The basic
geometric shape 162 of the primary bearing strut element 152 is a
circle as illustrated as a cut-away in FIG. 20A and as a complete
circle in FIG. 20B. At least one of the plurality of strut elements
inner edge 156 and outer edge 158 is tapered. The longitudinal body
154 has a porosity 155 to allow vascularity, bridging bone, and
other biologic elements to pass through. The porosity 155 of the
primary bearing strut element 152 ranges from 50 microns to 20 mm.
As shown in FIGS. 21A-21C, the porosity 155 may be comprised of
micropores, scaffold-like pores, or a fibrous matrix material,
respectively.
[0108] The outer edge 158 of the primary bearing strut element 152
is contoured to fit the subchondral bone 20 at the treatment site.
As shown in FIGS. 22A-22B, the outer edge 158 may be concave (FIG.
22A) such as the tibial plateau, convex (FIG. 22B) such as the
femoral condyle, or complex (not shown) with both concave and
convex curvatures, such as the femoral trochlea. The inner edge 156
includes scalloping for penetration of the subchondral bone 20
during insertion of the system 150. The outer edge 158 has at least
two grooves 151 (FIG. 20) formed therein an inner surface 153 of
the longitudinal body 154. In addition to the thickness taper that
exists between the outer edge 158 and inner edge 156, a concentric
taper 147 of the entire circle is present from the outer edge 158
to the inner edge 156 (FIG. 22C). This allows for subjacent
placement in a convex surface 149 as well as further preventing
subsidence. The degree of this taper 147 may range from 3-10
degrees.
[0109] FIG. 23 illustrates the placement of the joint support and
subchondral support system 150 in the subchondral bone 20 of the
femoral condyle and tibial plateau in accordance with the present
invention. The depth of penetration of the device 150 may vary
depending on the exact pathology being treated as seen in FIGS.
24A-24C such that it may be below the level of the subchondral
plateau (FIG. 24A), at the level of the subchondral plateau (FIG.
24B), or above the subchondral plateau, flush with the native
cartilage (FIG. 24C).
[0110] FIG. 25A is an enlarged perspective view of an insertion
holder 155 used in conjunction with the embodiment of FIG. 20
during insertion of the joint support and subchondral support
system or device 150 within the subchondral bone 20. The insertion
holder 155 has a proximal 157 and distal end 159. A plurality of
spikes 161 at the distal end 159 are configured to fit in at least
two grooves or vascular channels 151 at the outer edge 158 on the
inner surface 153 of the longitudinal body 154 to effectively hold
the device 150 during its insertion within the subchondral bone. It
is contemplated by the present invention that one insertion holder
155 may be used per device 150.
[0111] FIG. 25B illustrates the placement of the insertion holder
spikes 161 within each of the grooves or vascular channels 151 of
the embodiment of FIG. 20 during insertion of the device 150 within
the subchondral bone 20. During insertion of the device 150, the
plurality of spikes 161 at the insertion holder distal end 159 are
pushed downward in the grooves or vascular channels 151 and are
preferably extended past the inner edge 156. The plurality of
spikes 161 from the inserter holder 155 exit at the scalloped inner
edge 156 and are pushed deeper into the subchondral bone 20. The
device 150 and insertion holder 155 is then tamped into the
subchondral bone 20 and the insertion holder 155 is then removed
(not shown). The plurality of spikes 161 extended beyond the inner
edge 156 create channels in the subchondral bone 20 whereby
blood/marrow may access the outer edge 158 of the primary bearing
strut element 152 via the grooves or vascular channels 151. Grooves
151 may also be in the form of holes within the primary bearing
strut element 152.
[0112] As shown in FIG. 26, it is further contemplated by the
present invention that a bearing surface cover 163 may be attached
to the periphery of the outer edge 158 that serves to contain
marrow contents entering via the vascular channels or exogenous
substances, injected through the cover (i.e., cultured
chondrocytes). This cover 163 is made of either a thin netted or
woven material or biologic/synthetic membrane.
[0113] As shown in FIGS. 27A-27F, the geometric shape 162 of the
primary bearing strut elements 152 can be a circle (FIG. 27A),
multiple concentric circle (FIG. 27B), joined circles (FIG. 27C),
hexagon (FIG. 27D), or octagon (FIG. 27E) or other non-linear,
non-euclidean shapes, such as a hexagon with smoothed edges (FIG.
27F). The primary bearing strut elements 152 configured to be
joined together include at least three connecting struts 164 to
form a multiple concentric circle (FIG. 27B) in which each circle
166 of joined together primary bearing strut elements 152 is
connected to an adjacent circle 166 by the connecting struts
164.
[0114] It is further contemplated by the present invention that
single or multiple geometric shapes 162 may be configured to be
joined to each other in various patterns 168 (i.e., a honey-comb
configuration) (FIG. 28) such that the geometric shapes 162 may
penetrate the subchondral bone 20 and enable use with different
size cartilage lesions at the treatment site. The geometric shapes
162 may mirror the entire joint compartment if the entire
compartment is involved, i.e., trochlea, lateral patellar facet,
medial tibial platea, etc. The geometric shapes 162 may be inserted
within the subchondral bone 20 either piecemeal or monobloc via
antegrade insertion (i.e., from the joint surface).
[0115] The dimensions of the joint support and subchondral support
system 150 generally depend on the size of the lesion being
treated. In particular, the primary bearing strut elements 152
configured to be joined together in a geometric shape 162 each have
a diameter of from about 1 mm to about 5 cm and a height/depth of
from about 1 mm to about 3 cm.
[0116] FIG. 29A illustrates a cut-away view of the primary bearing
strut element 152 with a primary bearing flare 170. In a further
embodiment shown in FIG. 29B, the primary bearing strut element 152
includes a secondary bearing flare 172 extending below the strut
element 152. The secondary bearing flare 172 can be in the form of
either a vertical double tapered wing strut 174 or obliquely
extending arm 176. These secondary flares 172 serve to further
resist subsidence.
[0117] At least one active or passive dampening element 178 (FIG.
29B) is attached to the primary bearing strut element 152. The
dampening element may be inherent to the material properties of the
device 150, i.e., silicone-inject porous metal matrix. A dampening
element, such as a piezoelectric device, converts active mechanical
energy to heat or electric, thereby dissipating and dampening the
shock.
[0118] The joint support and subchondral support system 150 of the
present invention may be fabricated from virtually any
biocompatible material, including, but not limited to, metals,
metal alloys, carbon fibers, foam metals, ceramics, ceramic
composites, elastomer composites, elastomer-carbon fiber
composites, chambered or fluid-filled materials, metal matrices,
injectable gels, injectable composites with fluid and sold
matrices, bone or bone-composite or allografts, crystal or
hydroxyapatite materials, plastics (i.e., PEEK), polymers,
bioabsorbable composites (i.e., TCP/PLLA), or
combinations/composites of the above materials. The preferred
materials for the system 150 have inherent elastic or shock
absorbing properties.
[0119] Referring now to FIG. 30 in a further embodiment of the
present invention, the joint support and subchondral support system
180 includes a primary bearing strut element 182 of variable
geometry and thickness having a longitudinal body 184 and an inner
edge 186 and an outer edge 188. The longitudinal body 184 has a
porosity to allow vascularity, bridging bone, and other biological
elements to pass through. The outer edge 188 has at least two
grooves 189 formed therein an inner surface 190 of the longitudinal
body 184 and contoured to fit the subchondral bone 20 at the
treatment site. The system 180 further includes a contoured, porous
plate 192 having a variable shaped inner surface 194, outer surface
196, and peripheral surface 198 of variable thickness extending
between the inner surface 194 and outer surface 196, suitable for
insertion within the subchondral bone 20. The inner surface 194,
outer surface 196, and peripheral surface 198 each have a
respective concave portion 194A, 196A, 198A and a respective convex
portion 194B, 196B, 198B. The inner edge 186 of the primary bearing
strut element 182 is in direct communication with the contoured,
porous plate 192 within the subchondral bone being treated. The
contoured, porous plate 192 of the joint support and subchondral
support system 180 may include a plurality of surface dimples 202
and undersurface pimples 204 as previously described above.
[0120] FIG. 31 illustrates the placement of the joint support and
subchondral support system 180 in the subchondral bone 20 of the
femoral condyle and tibial plateau in accordance with the present
invention.
[0121] It is contemplated by the present invention that the joint
support and subchondral support system 180 may be inserted within
the subchondral bone 20 according to the insertion techniques
previously discussed above.
[0122] At least one active or passive dampening element 206 is
attached to the joint support and subchondral support system 180. A
dampening element, such as a piezoelectric device, converts active
mechanical energy to heat or electric, thereby dissipating and
dampening the shock.
[0123] As with the previous embodiments, the joint support and
subchondral support system 180 of the present invention may be
fabricated from virtually any biocompatible material, including,
but not limited to, metals, metal alloys, carbon fibers, foam
metals, ceramics, ceramic composites, elastomer composites,
elastomer-carbon fiber composites, chambered or fluid-filled
materials, metal matrices, injectable gels, injectable composites
with fluid and sold matrices, bone or bone-composite or allografts,
crystal or hydroxyapatite materials, plastics (i.e., PEEK),
polymers, bioabsorbable composites (i.e., TCP/PLLA), or
combinations/composites of the above materials. The preferred
materials for the system 180 have inherent elastic or shock
absorbing properties.
[0124] FIG. 32 illustrates the placement of the joint support and
subchondral support system 10, 50, 106, 150, 180 of each of the
aforementioned embodiments discussed above in subchondral bone 20
of a knee joint 22. The present invention contemplates that each of
the embodiments of the joint support and subchondral support system
10, 50, 106, 150, 180 may be used in combination with one another
to provide enhanced structural and dampening support to damaged
subchondral bone 20 adjacent to a body joint.
[0125] The above-described elements for each of the embodiments may
be varied in design, function, operation, configuration, materials,
and dimensions, and are not limited to the descriptions provided
herein.
[0126] Having now described the invention in accordance with the
requirements of the patent statutes, those skilled in the art will
understand how to make changes and modifications in the present
invention to meet their specific requirements or conditions. Such
changes and modifications may be made without departing from the
scope and spirit of the invention as set forth in the following
claims.
* * * * *