U.S. patent application number 16/132458 was filed with the patent office on 2019-02-07 for resilient arthroplasty device.
This patent application is currently assigned to iOrthopedics, Inc.. The applicant listed for this patent is iOrthopedics, Inc.. Invention is credited to Robert Thomas Grotz.
Application Number | 20190038416 16/132458 |
Document ID | / |
Family ID | 41202398 |
Filed Date | 2019-02-07 |
United States Patent
Application |
20190038416 |
Kind Code |
A1 |
Grotz; Robert Thomas |
February 7, 2019 |
RESILIENT ARTHROPLASTY DEVICE
Abstract
The disclosure is directed to a resilient implant for
implantation into human or animal joints to act as a cushion
allowing for renewed joint motion. The implant endures variable
joint forces and cyclic loads while reducing pain and improving
function after injury or disease to repair, reconstruct, and
regenerate joint integrity. The implant is deployed in a prepared
debrided joint space, secured to at least one of the joint bones
and expanded in the space, molding to surrounding structures with
sufficient stability to avoid extrusion or dislocation. The implant
has opposing walls that move in varied directions, and an inner
space filled with suitable filler to accommodate motions which
mimic or approximate normal joint motion. The implant pads the
damaged joint surfaces, restores cushioning immediately and may be
employed to restore cartilage to normal by delivering regenerative
cells.
Inventors: |
Grotz; Robert Thomas; (Las
Vegas, NV) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
iOrthopedics, Inc. |
Las Vegas |
NV |
US |
|
|
Assignee: |
iOrthopedics, Inc.
Las Vegas
NV
|
Family ID: |
41202398 |
Appl. No.: |
16/132458 |
Filed: |
September 16, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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15721910 |
Oct 1, 2017 |
10092405 |
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16132458 |
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12460703 |
Jul 23, 2009 |
9808345 |
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15721910 |
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61135820 |
Jul 24, 2008 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
A61F 2002/30754
20130101; A61B 17/842 20130101; A61F 2/4202 20130101; A61F
2250/0048 20130101; A61F 2/3603 20130101; A61F 2002/30594 20130101;
A61F 2/389 20130101; A61B 17/562 20130101; A61F 2/38 20130101; A61F
2002/30589 20130101; A61F 2002/30576 20130101; A61F 2002/30581
20130101; A61F 2/30721 20130101; A61F 2002/30563 20130101; A61F
2002/30757 20130101; A61F 2/32 20130101; A61F 2002/4212 20130101;
A61F 2/3872 20130101; A61F 2002/30019 20130101; A61F 2002/30688
20130101; A61F 2/30756 20130101; A61F 2/40 20130101 |
International
Class: |
A61F 2/30 20060101
A61F002/30; A61F 2/42 20060101 A61F002/42; A61F 2/32 20060101
A61F002/32; A61F 2/36 20060101 A61F002/36; A61F 2/38 20060101
A61F002/38; A61F 2/40 20060101 A61F002/40 |
Claims
1. A resilient implant for the foot or ankle comprising: a first
wall, a second wall, a side wall extending between the first wall
and the second wall, a plurality of chords or anchors for securing
the implant to at least one bone or one ligament.
2. The resilient implant of claim 1, wherein the implant comprises
a mesh material.
3. The resilient implant of claim 1, wherein the first wall, the
second wall and the side wall define an interior portion.
4. The resilient implant of claim 3, wherein the interior portion
is inflated with a resilient material.
5. The resilient implant of claim 3, wherein the interior portion
is inflated with gas, liquid, gel, slurry, curable polymer, foam,
sponge or combinations thereof.
6. The resilient implant of claim 4, wherein the resilient material
in the interior portion maintains spacing between the first wall,
the second wall and the side wall.
7. The resilient implant of claim 4, wherein the resilient material
in the interior portion provides support between the first wall,
the second wall and the side wall.
8. The resilient implant of claim 1, further comprising tissue
regeneration agents.
9. The resilient implant of claim 1, wherein the first wall, the
second wall and/or the side wall are multilayered.
10. The resilient implant of claim 1, wherein the first wall, the
second wall and/or the side wall have a variable resiliency.
11. The resilient implant of claim 10, wherein the distance between
the first wall and the second wall varies throughout the
implant.
12. The resilient implant of claim 1, wherein the implant has a
center.
13. The resilient implant of claim 12, wherein the center of the
resilient implant's rotation will change with gait or the motion of
the tibia.
14. A resilient implant for the foot or ankle comprising: a first
wall, a second wall, a side wall, a plurality of chords or anchors
for securing the implant to at least one bone or one ligament,
wherein one of the first wall, second wall and side wall engages
the tibia.
15. The resilient implant of claim 14, wherein one of the first
wall, second wall and side wall which does not engage the tibia,
engages the calcaneus.
16. The resilient implant of claim 14, wherein the first wall, the
second wall and/or the side wall have a variable resiliency.
17. The resilient implant of claim 14, wherein the distance between
the first wall and the second wall varies throughout the
implant.
18. The resilient implant of claim 14, wherein the distance between
the first wall and the second wall is from 0.5 mm to 5 mm.
19. The resilient implant of claim 14, wherein the implant has a
center.
20. The resilient implant of claim 14, wherein the center of the
resilient implant's rotation changes with gait or motion of the
tibia.
Description
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Non-provisional
Ser. No. 15/721,910 filed on Oct. 1, 2017, which claims the benefit
of claims the benefit of U.S. Non-provisional Ser. No. 12/460,703
filed on Jul. 23, 2009 and now U.S. Pat. No. 9,808,345, which
claims the benefit of U.S. Provisional Application No. 61/135,820
filed on Sep. Jul. 24, 2008, all of which are incorporated herein
by reference in their entirety.
BACKGROUND OF THE INVENTION
[0002] This invention relates to arthroplasty, and more
particularly, to an implant for use in arthroplasty. When hyaline
articular cartilage is damaged, it breaks down and joint space is
lost. Inflammatory enzymes such as from the Cox-1, Cox-2 and/or
5-Lox systems, are released and loose bodies form adding to the
degradation of joint function. Such joint damage is conventionally
treated by physical therapy, analgesics, pain medication and
injections. When these treatments fail, the traditionally accepted
treatment option is arthroplasty implantation or replacing the
joint with an artificial joint construct. Current arthroplasty
techniques typically use "plastic and metal" implants that are
rigid and which ultimately fail due to loosening or infection.
Conventional materials for the artificial joint components include
chrome-cobalt-molybdenum alloy (metal) and high molecular weight
polyethylene (plastic). Each is often fixed by a cement-like
mixture of methyl methacrylate to the ends of the bones that define
the joint that is the subject of the arthroplasty, or coated with a
surface that enables bone ingrowth. Current hip joint replacements
typically last about 10-15 years and knee replacements typically
last about 5-10 years. Ankle joint replacements, on the other hand,
are not very successful, and often fail in the first several years
after surgery.
[0003] Conditions requiring arthroplasty include traumatic
arthritis, osteoarthritis, rheumatoid arthritis, osteonecrosis, and
failed surgical procedures.
SUMMARY OF THE INVENTION
[0004] The present invention is directed to an orthopedic implant
configured for deployment between opposing members of a joint
structure that addresses many of the shortcomings of prior
artificial joints. The arthroplasty implants embodying features of
the invention are configured to preserve joint motions while
removing the pain and dysfunction following the development of
arthritis or joint injury. The arthroplasty implant in accordance
with the present invention achieves improved physiologic motion and
shock absorption during gait and acts as a resilient spacer between
moving bones during limb movement. The combined characteristics of
the implant include anatomic design symmetry, balanced rigidity
with variable attachment connections to at least one of adjacent
normal structures, and durability which addresses and meets the
needs for repair or reconstruction thus far missed in the prior
art. The implant should be secured to at least one of the bones of
the joint structure.
[0005] More specifically, the resilient implant embodying features
of the invention has a first wall configured to be secured to a
first bone of the joint structure by one or more appendages such as
a skirt or one or more tabs and a second wall configured to engage
a second and usually opposing bone of the joint structure. A side
wall extends between the first and second walls of the implant and
together with the first and second walls preferably defines at
least in part an inner chamber or space between the first and
second walls. The implant is configured to provide linear or
curvilinear and/or rotational motion between the first and second
bones which mimics or approximates the natural motion between these
bones. The inner chamber or space is configured to maintain a
filler material therein such as an inflation fluid or a resilient
material and preferably to maintain spacing and provide support
between the interior of the first and second walls to avoid
significant contact therebetween. The walls of the implant are
preferably sealed about the periphery thereof to maintain the
interior chamber in a sealed condition to avoid loss of inflation
fluid or filling media. The side wall or walls may be formed from
the edges or periphery of the first and second walls. The
properties of the implant walls and the interior are controlled to
provide the particular resiliency desired for the joint in which
the implant is to be placed as well as any desired motion between
the first and second walls. A conduit may extend from a source of
inflation fluid or other filling medium to the interior of the
implant to facilitate expansion of the implant after deployment
within the joint. The inflation fluid may be a gas, a liquid, a gel
or a slurry, or a fluid that becomes a suitable resilient solid
such as a curable polymer. Selection of the inflation or interior
filling medium may depend upon the nature of the joint structure in
which the implant is to be deployed, its anatomy, pathophysiology,
and the properties of the implant material.
[0006] There may be several alternative embodiments depending upon
the site in which the implant is to be deployed. For example, the
polymer forming the side wall may be semi-compliant or elastic and
the inflation fluid may be incompressible (e.g., a liquid).
Alternatively, the polymer forming the side wall may be
non-compliant (non-elastic) and the inflation fluid or filling
medium may be compressible, e.g., a gas or a resilient polymeric
foam or sponge-like solid that may have a closed cell structure.
The first and second walls of the implant need not have the same
properties as the side wall. For example, parts of the implant such
as the side wall portion may be compliant and the first and second
wall portions in contact with the bone or other joint structure may
be non-compliant. Additionally, the various walls or portions
thereof may also be reinforced with non-compliant or semi-compliant
polymer strands, beads or gel coating such as biologic or polymer
latticework. The thicknesses of the first, second and side walls
may be varied to accommodate for the needs of the joint structure
from the standpoint of strength, elasticity and wear resistance.
Moreover, the walls of the implant may be provided with joint
tissue regeneration agents that rebuild the joint structure in
which the implant is deployed. The regeneration agent may be
incorporated into the wall of the implant prior to delivery or
placed between the surface of the implant and the joint structure
which it contacts after delivery. All or part of the walls of the
implant may also be made of a biodegradable polymer, by minimally
manipulated autograph, allograph or xenograph tissues, or a
combination thereof. The method of surgery may incorporate a
progressive application of the implant embodiments depending upon
clinical needs.
[0007] The implant is preferably formed of suitable biocompatible
polymeric materials, such as Chronoflex, which is a family of
thermoplastic polyurethanes based on a polycarbonate structure (Al,
the aliphatic version, Ar, the aromatic version and C, the casting
version) available from AdvanSource Biomaterials, Corp. Other
polymers include Bionate 80, 90A, 55 or 56, which are also
thermoplastic polyurethane polycarbonate copolymers, available from
PTG Medical LLC., an affiliate of the Polymer Technology Group
located in Berkeley, Calif. Other commercially available polymers
include Purisil 20 80A which is a thermoplastic silicone polyether
urethane, Carbosil 20 90A which is a thermoplastic silicone
polycarbonate urethane and Biospan which is a segmented
polyurethane. These polymers are available as tubing, molded or
dipped components, solution, pellets, as a casting and as a cast
film for the side and first and second walls. The implant may be
formed by casting, blow molding or by joining sheets of polymeric
material by adhesives, laser welding and the like. Other methods of
forming the implant may also be suitable. The walls may also be
provided with reinforcing strands which are located on the surface
of the walls or incorporated within the walls. The implant material
should be biocompatible, non-toxic, and non-carcinogenic and should
be resistant to particulation.
[0008] The present invention provides an improved joint implant
which is designed to endure variable joint forces and cyclic loads
enabling reduced pain and improved function. Depending upon the
particular joint involved there may be linear or curvilinear motion
between the first and second walls, rotational motion between the
first and second walls or both linear and curvilinear motion and
rotation motion between the first and second walls. Preferably, a
space is maintained between the inner surfaces of the first and
second walls to avoid erosion and wear therebetween.
[0009] The resilient arthroplasty implant embodying features of the
invention is preferably deployed as a minimally invasive procedure
to deliver the implant into a prepared space in a preselected joint
structure, where upon it is inflated to create a cushion, to cover
damaged or arthritic cartilage and to be employed to deliver stem
cells or living chondrocytes or other tissue regeneration agents.
The goal of such deployment is to reduce pain and improve function,
to reverse arthritis, to fill in osteochondral defects succinctly,
thereby avoiding living with both dysfunctional and ablative
metal/plastic prostheses or the pathophysiologic state
necessitating the procedure. The operative plan is simple,
systematic, and productive of new joint space with regrowth
potential involving joint debridement by routine arthroscopic
methods or steam application, followed by implantation of the
implant. The implant provides three things, namely a covering or
patch for the damaged or worn joint surface, an inflated cushion to
pad gait as in normal walking in the lower extremity, and delivery
of regenerative cells on the cartilage remnant surface. The stem
cells may be injected as the implant is being expanded and/or
directed into the adjacent hyaline cartilage via an implant coating
or perfused cell template. Viscolubricants such as Synvisc or
Hyalgan, analgesics such as Lidoderm, anti-inflammatory and/or
antibiotic coatings as well as those stimulating cell growth may
accompany the composite external implant. The implant is left in
place as long as feasible, at least until regenerative cells can
attach to the adjacent natural joint surface (usually in about 24
hours), or until wound healing (which may take up to 28 days or
more depending on the joint structure). Preferably, the implant is
designed stay within the joint structure for years, providing inert
padding, cushioning and a new cell source. The implant may be used
in weight bearing and non-weight bearing interfaces. Animal usage
of the implant, such as in horses and dogs, will benefit following
hip and knee injuries. The implant is intended primarily for
mammalian use.
[0010] These and other advantages of the invention will become more
apparent from the following detailed description and the attached
exemplary drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a schematic cross-sectional view of an idealized
joint structure having first and second bones with an implant
having features of the invention disposed within the space between
the opposing bones of the joint structures.
[0012] FIG. 2 is similar to FIG. 1 illustrating curvilinear
movement between the two opposing bones.
[0013] FIG. 3 is a transverse cross sectional view taken along the
lines 3-3 in FIG. 1 illustrating rotational movement between the
two opposing bones.
[0014] FIG. 4 is a perspective view, partially in section, of an
implant embodying features of the invention with an enlarged upper
portion prior to implantation.
[0015] FIG. 5 is an elevational view of the implant shown in FIG. 4
mounted on the head of a patient's femur.
[0016] FIG. 6 is a cross-sectional view of the implant shown in
FIGS. 4 and 5 deployed between the head of a patient's femur and
acetabulum after release of traction to allow for the bones to
settle into their natural albeit pathologic angles of repose.
[0017] FIG. 7 is an elevational view of a resilient arthroplasty
implant with a smaller upper portion than that shown in FIGS. 4-6
that has been deployed between the head of patient's femur and the
acetabulum of the pubic bone.
[0018] FIG. 8 is an elevational anterior view of a left proximal
femur with an implant placed over the femoral head portion of the
hip joint as shown in FIG. 7, in partial cross section, to
illustrate details thereof.
[0019] FIG. 9 is a lateral elevational view of a femur with the
implant shown in FIG. 6, as viewed from the "side of the body" or
lateral hip aspect.
[0020] FIG. 10 is a superior view of a femur with the implant shown
in FIG. 7.
[0021] FIG. 11 is an inferior view of the hip joint invention
iteration or implant in FIG. 10.
[0022] FIG. 12 is a superior or cephalad view of a patient's hip
with a resilient implant having features of the invention, viewed
from the head of the patient or from a cephalad to caudad
direction.
[0023] FIG. 13 is a lateral view of the patient's ankle having a
resilient arthroplasty device implant which embodies features of
the invention between opposing joint structures.
[0024] FIG. 14 is a mortise (30 degree oblique AP) view of the
patient's left ankle with implant shown in FIG. 13.
DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION
[0025] The present invention is directed to arthroplasty implants
and procedures for a wide variety of joints such as, for example,
hips, knees, shoulders, ankles, elbows, wrists, fingers, toes,
temporomandibular joints and the like, but for clarity, as well as
brevity, the discussion herein will focus on an implant for a hip
joint and an implant for replacing the talus bone of a patient's
ankle.
[0026] FIG. 1 is a highly schematic idealized view of an implant 10
embodying features of the invention that is deployed within a joint
structure having a first bone 11 and a second bone 12. The implant
10 has a first wall 13, a second wall 14, and a side wall 15 which
define the implant interior 16 which contains filling material 17.
The first wall 13 is secured to the end of the first bone 11 by the
skirt 18 that extends from the first wall 13 and the second wall 14
engages the end surface of the second bone 12 and may also be
secured thereto. The side wall 15 extending between the first and
second walls 13 and 14 defines at least in part the implant
interior 16 which is filled with filling material 17. The inner
surfaces of wall 13 and skirt 18 preferably conform to the
particular surface of the head of the patient's first bone 11. The
outer surface of the second wall 14 is preferably configured to
conform to the end surface of the second bone 12. The drawings are
highly schematic and do not depict details of the joint surface
features such as of the end of the first bone 11 or the end of the
second bone 12, since human pathology and variation reflects both
the patient's immediate and evolving pathophysiology.
[0027] The edge of the implant 10 shown in FIG. 1 has a depending
skirt 18 to secure or anchor the implant to the end of bone 11, but
may have one or more depending tabs that may be employed for
similar functions as will be discussed in other embodiments. The
skirt 18 (and/or tabs) may tightly fit about the end of the first
bone 11 as shown, or the skirt can be secured by adhesive (e.g.
methyl methacrylate, bone ingrowth) to the supporting bone
structure or be mechanically connected by staples, screws and the
like. Moreover, the lower portion of the skirt 18 may be secured by
a purse string suture or a suitable strand (elastic or tied) that
is tightly bound about the outside of the skirt.
[0028] As shown in FIG. 1, the implant interior 16 between the wall
13 and the wall 14 is filled with filler material which aids in
maintaining the desired implant dynamics within the joint
structure. The nature of the filler material such as a fluid and
the characteristics of the walls 13, 14 and 15 may be selected to
maintain a desired spacing between the walls in order to
accommodate the pressure applied by the bones of the joint
structure to the implant 10 and to allow suitable motion between
the first and second walls 13 and 14 of the implant 10 which
facilitate bone motion which mimics or approximates normal movement
for the joint members involved such as shown in FIGS. 2 and 3.
Alternatively, as mentioned above, the inner chamber may be filled
with resilient material to provide the desired spacing, pressure
accommodation, while allowing desired physiologic motion between
implant layers. The implant 10 is preferably configured to be
shaped like the joint space and bone surfaces being replaced or to
fill the void produced by injury or disease so that the natural
joint spacing and cushioning of the joint interface is restored
toward normal physiologic appearance and function. Fluids such as
saline, mineral oil and the like may be employed to inflate the
implant.
[0029] Linear or curvilinear movement between the first and second
walls 13 and 14 as a result of movement of the first and second
bones 11 and 12 is illustrated by the arrow shown in FIG. 2.
Rotational movement about the bone axis between the first and
second walls 13 and 14 as a result of axial rotation between the
first and second bones 11 and 12 is illustrated by the arrow shown
in FIG. 3. While not shown in the drawings, there may be slippage
between the second bone and the second wall in addition to wall
movements within the implant per se to provide desired joint
movements. The skirt 18 is designed to secure the general implant
to the joint structure so as to avoid dislocation of the implant.
Movement of the joint with the implant 10 in place will be a shared
function of both the moving opposing walls 13 and 14 of the implant
but also a function of the movement of the wall 14 which may be
less attached to the joint members. There may be slight movement
between the skirt 18, wall 13 and the first bone 11. As shown in
FIG. 2 one side of the side wall 15 is in compression and the other
is stretched to accommodate bone interface movement. The walls 13
and 14 may be thicker is some areas to accommodate particular loads
and the side wall 15 may be thinner and more elastic to accommodate
rolling and stretching thereof.
[0030] The interior 16 of implant 10 is adjustably filled by the
physician from an appropriate source thereof after the implant is
deployed to ensure that the pathologic joint space becomes a
resilient cushion again which aids restoration of worn or damaged
cartilage interfaces in the joint by covering cartilage defects
with the implant material, cushioning the joint and defects therein
and delivering cell regeneration agents. In one embodiment, the
arthroplasty implant comprises a bio-compatible inflatable member
that is filled with a biocompatible fill material such as a gas,
liquid, gel or slurry, or fluid that becomes a resilient solid to
provide relative movement between the first and second walls 13 and
14. The filling or inflation media may be inserted through an
injection valve site leading to the cannula which delivers the
material into the interior of the implant. In an alternative
embodiment, the implant may be filled with or have an interior
formed of biologically compatible resilient material, e.g. a closed
cell sponge filled with suitable fluid that is inserted into the
interior of the implant prior to the implant's deployment or
injected into the interior after the implant is deployed at the
joint site. The interior of the implant may be provided with
lubricious material to facilitate movement between the inner wall
surfaces and to minimize contact wear therebetween. The polymeric
walls of the implant may be impregnated with or otherwise carry
tissue regeneration agents such as stem cells, living chondrocytes,
and/or genes to repair joint surfaces.
[0031] The implant can be used in a variety of joints where the
implant replaces a bone on bone surface and cushions the
interaction between the articular ends of any two bones, such as at
the femoral-acetabular interspace of a patient's hip, the humerus
and glenoid scapular component in the shoulder, the femoral tibial
and patella femoral knee interfaces, the replacement of talus bone
in the human ankle between the tibia and calcaneus and the like.
Where the implant is substituting or enhancing articular cartilage,
the rigidity can be reduced or enhanced to maximize conformation
changes that arise during motion as enabled by the two opposing
walls and intended inner space, coupled with considerations in any
joint surgical reconstruction with accommodation to or
amplification of the existing joint ligaments, tendons or dearth
thereof. The implant 10 may be deflated and removed by minimally
invasive surgery, for example after the implant has served its
purpose of regenerating tissue or if another clinical condition
warrants its removal. However, it may not be clinically necessary
to remove the implant even if inflation is lost, since the two
remaining functions of patching the injured cartilage, and
delivering restorative cells may justify implant retention.
[0032] FIG. 4 is a perspective view, partially in section,
illustrating a hip implant 20, similar to that shown in FIG. 1, but
with a much larger upper portion. The large upper portion of the
implant 20 has a first wall 21, a second wall 22 and a side wall 23
which define at least in part the interior 24. Skirt 25 depends
from the first wall 21 and secures the first wall 21 to the end of
the patient's femur 26 as best shown in FIGS. 5 and 6. FIG. 6
illustrates the implant mounted on the head of the femur 26 with
the second wall 22 of the filled upper portion configured to engage
the corresponding acetabulum 27 of the patient's pelvic bone 28.
The skirt 25 surrounds the head of the patient's femur 26 and
secures the implant 20 thereto. In this embodiment, the enlarged
upper portion of the implant creates overlapping layers, like a
redundant membrane, in the side wall 23 between the first and
second walls 21 and 22 to accommodate the normal movement of the
first or second. This provides greater motion between the femur and
the acetabulum and also provides implant stabilization over the
head of the femur 26. This structure also accommodates variation in
individual joints that occur from patient to patient.
[0033] In the embodiment shown in FIGS. 4-6 the first wall 21 does
not extend across the entire end of the patient's femur as in the
embodiment shown in FIGS. 1-3. However, the implant 20 may be
designed so that first wall 21 may extend over the head of the
femur as shown in FIGS. 1-3 (and FIGS. 7-12 discussed hereinafter).
The second wall 22 and the side wall 23 tend to roll as the femur
26 moves within the acetabulum 27.
[0034] Prior to deploying the implant embodying features of the
invention, the cartilage lining the joint is prepared by removing
hyaline or fibro cartilage flaps or tears, and areas of chondral
advanced fissuring are excised or debrided to create precisely
defined defects surrounded by stable normal remnant hyaline
cartilage with vertical edges in relation to the damaged surface.
It is these defects of the cartilage previously normal surface into
which new living cells may be injected or otherwise inserted, and
allowed to aggregate by the implant interpositional arthroplasty
proximate expanded compressive external wall material. Synovitis
invading the joint periphery may be vaporized and extracted
conventionally or by the use of steam. Areas of greater cartilage
damage are removed for subsequent regeneration and the less
afflicted areas having stable cracks are treated to seal or weld
the cracks. Areas where the tugor or consistency or minimally
damaged cartilage can be preserved are intentionally saved rather
than destroyed so as to support the normal spacing and gliding
opportunity of the more normal joint interface. Thus, normal
cartilage is left behind and abnormal cartilage is removed with the
implant making up for the deficiencies. With the present invention,
it is preferred to avoid joint dislocation so as to preserve
natural innervations and vascularity and thus preserving the blood
supply afforded by the medial and lateral circumflex arteries for
the hip joint to the femoral head.
[0035] Joint preparation is usually performed under a brief general
anesthetic of outpatient surgery. A muscle relaxant combined with
traction (e.g. 60 pounds force for a hip implant) opens the joint
wider to permit improved visualization for joint preparation and
implant installation, increasing the space between the remnant
cartilage from about 3 up to about 12 mm. Increasing the space
allows the surgeon to wash out noxious enzymes, to remove invasive
synovitis, to remove loose bodies, to prepare osteochondral defects
ideally and otherwise prepare the joint for the implant. Partial or
complete inflation of the implant will usually precede release of
traction. Regeneration agents or cells are inserted with the
implant or as a fluid or 3-D template prior to release of traction
and wound closure. It is preferred to perform joint debridement,
implant deployment and application of cell regeneration agent, e.g.
stem cell application, under the same anesthetic. As described by
several companies in the Stem Cell Summit held in New York, N.Y. on
Feb. 17, 2009, it is desirable to obtain an aspiration of the
patient's bone marrow from the iliac crest after anesthesial
sterilely at the beginning of the operation. The intraoperative
technologist will "dial in the cells" to regenerate areas of
maximum pathophysiology while the surgeon debrides or otherwise
prepares the joint and inserts the implant, placing the cells at
the best time. Cell implantation may also occur as a secondary or
tertiary reconstructive treatment adjunct.
[0036] FIG. 7 is an elevational view, partially in section, of an
alternative resilient implant 30 deployed within a patient's hip
structure comprising the head of the patient's femur 31 and the
acetabulum 32 of the patient's pelvic hip bone 33. The upper
portion of the implant 30 is smaller than that shown in FIGS. 4-6.
Details of the interior of the joint are not provided such as
cartilage, ligaments and the like for the purpose of clarity. The
resilient implant 30 embodying features of the invention is
disposed within the space between the femur 31 and the acetabulum
32. FIGS. 7-11 illustrates the implant 30 mounted on the head of
femur 31 without the pressure from the acetabulum 32 for purposes
of clarity.
[0037] The implant 30 shown in FIGS. 7-12 is shaped like a half an
orange rind or a hemisphere for a hip joint. The implant 30 has a
first wall 34 seen in FIG. 8 which is secured to the head of the
femur 31 by a plurality of depending tabs 35. The tabs 35 may be
attached to the femur 31 by a suitable adhesive or mechanically
such as by a screw or pin. The second wall 36 of the implant
engages the acetabulum 32, but it also may be provided with tabs
and the like for securing the second wall the acetabulum 32.
[0038] The side wall 37 extends between the first and second walls
34 and 36 to form an interior 38 which receives filling material 39
through tube 40. The implant 30 would also be appropriate for the
humeral head in the shoulder or one condyle of the knee or of the
humerus, but other shapes may be desired for other joint
configurations whether relatively flat as in the thumb base, or
more inflated toward a ballooning construct as in the ankle when
the talus bone is collapsed. In many embodiments the implant 30 is
a weight bearing spacer that will allow joint motions to approach
normal, whether filling the space left by an entirely collapsed
peripheral joint bone or the space of ablated cartilage proximate
surfaces diffusely as in osteoarthritis or succinctly as in
osteonecrotic defects or localized trauma. The walls 34 and 36 may
be used as a membrane for holding living cells in proximity of the
osteochondral defect long enough for the cells to attach (e.g. 24
hours) or to deeply adhere (up to 28 days) or return to normal (up
to one year). Weight bearing will be expected to increase as distal
lower extremity joints are treated.
[0039] Motion is believed to be primarily between the spaced walls
of the implant peripherally secured to joint structures, although
some motion may occur between the implant and the joint surfaces
(as with current bipolar hip hemiarthroplasties). As shown in FIG.
12, the implant 30 may be provided with a slot 41 extending from
the periphery 42 of the implant to a centrally located passage 43
through the implant to accommodate the ligament of the head of the
femur for hip implants. Knee implants (not shown) may have two
slots leading to separate passages for receiving the anterior and
posterior cruciate ligaments. Implants for other locations may have
similar variable structures to accommodate anatomical features.
Implant walls 34 and 36 should have sufficient inherent flexibility
to mold to the existing deformities imposed by either natural
ligament, bone, tendon and remaining cartilage deformities of the
internal joint space filled as a cushion. The wall exteriors may be
flat or formed with random or specific patterns for purposes of
glide or trends for traction against adjacent surfaces, or as sulci
or venues for cell delivery materials.
[0040] A separate portal or tube (not shown) or the existing
conduit 40, may be used to extract noxious inflammatory enzymes
that can be aspirated at appropriate clinical intervals.
Inflammatory enzymes in the COX1, COX2 and or 5LOX pathways can be
extracted. Viscolubricants can be injected into the interior of the
resilient arthroplasty device through existing conduit 40 or
through a long needle to aide in distension, expansion, lubrication
(with predetermined microporosity).
[0041] The ankle version of the arthroplasty implant 50 of the
present invention shown in FIGS. 13 and 14 has basically a square
transverse cross-section that must take into account supratalar
ankle dorsi/plantar flexion, subtalar eversion/inversion motions,
ligament fixation needs, and the accommodation to existing bony
architecture as implant variables accounting for the ipsilateral
joint pathophysiology. The implant 50 has a first wall 51, a second
wall 52 and a side wall 53 which extends between the first and
second wall. The exterior of the implant 50 may have a mesh
material 54 with a plurality of chords 55-61 for securing the
implant 50 to adjacent bones or to remnant ligaments which are
attached to adjacent bones.
[0042] The implant 50 may be inflated with gas and/or liquid to
open wider the space between the tibia above and the calcaneus
below to accommodate collapse of the talus bone as in the
flattening which succeeds talus fracture with avascular necrosis,
or it may be filled with a liquid that becomes a resilient solid.
The instant center of the implant's rotation will be constantly
changing, with the talus implant mainly stable and with the tibia
moving over it. Deformation with weight bearing during the average
human's 10,000 daily steps or 2-4 million annual gait cycles
required by the stance and walking of normal activities of daily
living, must be balanced between sufficient solidarity of the
implant to maintain axial load, avoiding circumferential stress,
and shear forces imposed by the tibia distal plafond on the dorsal
ankle implant allowing stance and gait of the patient while
avoiding implant migration or failure. Further accommodation to
lateral forces imposed by the boney medial and lateral malleoli,
need to be endured through the cyclic load of walking, while
collapsing with enough give to absorb shock and to match the shape
of surrounding structures of bone and ligament tissue. Whereas the
axial load between the distal tibia through the talar implant to
the dorsal calcaneus will be loaded during stance and especially
while walking on a level plane for supratalar motion, the lateral
forces will be loaded particularly with subtalar motion while
walking on an uneven plane or with inversion/eversion.
[0043] The dimensions of the various implant walls will vary
depending upon the material properties thereof as well as the needs
for a particular joint. Additionally, the first and second walls
may require a thickness different from the side wall. Generally,
the implant may have a wall thicknesses of about 0.125 mm to about
3 mm, preferably about 0.5 mm to about 1.5 mm. The spacing between
the first and second wall within the interior can vary from about
0.5 mm to about 5 mm for most joints (except for the implant for an
ankle when an entire collapsed bone space is being replaced),
preferably about one to five centimeters to fill between the tibia
and calcaneus. In the ankle invention version of the implant, the
amount of inflation of the implant per se will be directly
proportional to the amount of talus bone collapse between the
distal tibia and proximal calcaneus--thus as much as 5 cm implant
distension or expansion may be required to be maintained between
superior and inferior surfaces in FIG. 13 of the talus, while as
much as 10 cm anterior and posterior expansion may be required for
the ankle implant between the posterior soft tissues such including
the Achilles tendon and the anterior navicular bone as relates to
the talus as seen in FIG. 13.
[0044] The method of insertion for the hip joint invention will be
a minimally invasive approach, ideally arthroscopically
facilitated, as long as the surgical timing and result quality
permit smaller incisions. The hip patient will be placed in the
lateral decubitus position (lying non-operative side down on the
operating table) with a stabilizing operating table pole and pad
apparatus positioned to fix the pelvis. The external stabilizing
table and attachments will include a padded metal pole beneath the
pubis or pelvic bone from posterior to anterior, along with other
external anterior and posterior pelvic stabilizing paddles. The
affected leg will be attached beneath the knee with a distracting
mechanism that applies about 60 pounds of distal force to open the
hip joint about 1 cm once the patient is under general anesthesia.
The hip joint is arthroscopically debrided through at least one
anterior 0.5 cm incision and one posterior 0.5 cm incision, to
remove from the femoral head acetabular (ball and socket) joint
arthritic debris such as synovitis, loose bodies and noxious
inflammatory enzymes. In certain cases a larger open incision may
be needed. A smoothing or electronic/ultrasonic/steam or other
chondroplasty method may be performed to make the remaining
cartilage smoother to better accommodate the hip implant, and
protuberant osteophytes or lateral bone overgrowths may be
arthroscopically removed or if needed by open excision. A lateral
hip incision may be required between 2 and 10 centimeters in length
to deal with deformities and/or to insert the implant. In cases of
major deformities appropriate reconstruction will add to the basic
procedure.
[0045] Once the joint is open and cleared, the hip implant will be
inserted laterally and fixed via the skirt or tabs to the adjacent
structures including the peripheral femoral head and/or acetabular
rim. Preferably, the implant is inserted arthroscopically through a
cannula about 10 mm in diameter with the implant in the deflated
construct, and once inside the prepared joint space and secured
therein by the skirt or tabs, the implant will be distended or
inflated with gas, gel, fluid or fluid that becomes a resilient
solid to fill the original natural space of about 0.5 cm between
the upper acetabulum and lower femoral head, covering as much of
the upper hip joint as required as the implant expands to fit the
space. Tensioning will be by the surgeon's sense of proper pressure
application aided by a gauged syringe for insertion of
viscolubricants such as Synvisc, Hyalgan, Supartz and/or analgesics
such as lidocaine gel. The insertion of liquids to the joint per se
may be directly, through a cannula to the joint space previously in
place for debridement, and or via a cannula or tube that is not
part of the original implant assembly. Once the joint is cleaned,
the implant is inserted and appropriately fixed to avoid extrusion
or dislocation thereof. This may be via attachment of the implant
tabs and/or by a combination of tab use plus intended friction
created by implant surface coverings (analogous to Velcro) or a
draw string at the smaller base of the implant.
[0046] The walls of the implant embodying features of the invention
may be composite structures. For example, the innermost layer may
be impervious to preclude escape of inflation or other filling
media, a central layer may be porous or otherwise contain treatment
or cell regeneration agents, and the outer layer may be a thin, but
strong layer of a thermoplastic such as a thermoplastic
polyurethane which has microporosity sufficient to allow passage or
egress of treatment or cell regeneration agents from the central
layer. The degree of microporosity to enable egress of treatment or
cell regeneration agents from the central layer is found in polymer
layers such as Chronoflex or Bionate 55. The external wall of the
implant may be coated and/or impregnated with a latticework of
polymer surface sprayed or layered on the outside of the implant to
promote cartilage tissue regeneration. This most external surface
coating may contain living chondrocytes as in the Carticel
procedure by the Genzyme company, and/or may contain stem cells
with directed gene mutations to enhance adherence of the coating to
the implant. The living cells may be imposed in between troughs
while the surface areas of prominence may be used for space
validation, traction, and cell protection.
[0047] The implant embodying features of the invention may be used
in a series of treatments wherein the first treatment involves use
of autologous or minimally manipulated allograph interpositional
tissues or xenograph, the second treatment involves the use of the
same type of tissue added to stem cells or chondrocytes and the
third treatment involving deployment of the implant if the first
two fail or are ineffective.
[0048] The implant may be provided with latticework or other
reinforcing strands, preferably on the exterior or within the wall
thereof to control the maximum expansion of the implant when
deployed at the orthopedic site.
[0049] The method of insertion of the ankle implant generally will
be through an anterior surgical ankle approach or tendon separating
incision from the distal tibia to the proximal talus (or calcaneus
if the talus is absent), removing and reconstructing portions of
the superior and inferior ankle extensor retinacula only to the
extent required to gain access to the cleared tibiotalar space.
Analogous to the hip joint insertional method, the ankle joint will
be prepared arthroscopically under general anesthesia, and may
benefit from distal distraction as in total ankle joint replacement
surgeries with the DePuy Agility technique pinning above and below
the ankle joint and then distracting it. The degree of distraction
required in all joints to which this invention is applied,
including but not limited to those of all appendicular skeletal
structures such as the shoulder, elbow, wrist, phalanges, hip,
knee, and ankle, will depend both on the nature anatomy and located
pathophysiology that must be accommodated on a case by case basis
and said distraction may be a combination of body position using
gravitational forces and/or superimposed distracting devices. In
the ankle, the surgeon will be developing the interval between the
extensor hallucis longus and anterior tibial tendons. Injury tissue
is removed, and the implant inserted fitting as preplanned. The
implant surface may be provided with roughness, e.g. external mesh,
to control movement by friction as described above for the hip
joint, and/or attached fixation cords or tabs to connect to
proximate ligaments or adjacent boney structures may be used at the
surgeon's discretion to balance implant location stability and
integrity, with the need for functional joint movements.
[0050] Over time, ingrowth of repair tissue aids in fixation and
stability externally to the implant, while the soft cushioning
implant interior will absorb forces across the joint surfaces and
permit proper motion. The tugor or wall tension of the implant as
well as the inside distension of the implant per se can be adjusted
by adding or removing the inflation substance to the implant's
interior space.
[0051] Accordingly, the present invention provides a new approach
to arthroplasty that involves a resilient implant device deployed
between bones of the joint. Whereas a joint is comprised of the
interface between bone cartilage space cartilage bone, in certain
joint spaces such as the knee, the invention cushion may expand to
fit the spaces between both "knee joints"--the femoral tibial
involved on standing or walking on a level plane, and the patella
femoral bones of the knee more involved on stair ascent and decent.
For example, pressures behind the knee cap or patella when lying
are zero, when standing are 0.7 times body weight, and when going
up and down the patella femoral pressures are 3-4 times body
weight. Thus, the implants will need to accommodate all the normal
body functional pressures and complex space movements, as described
above also in the ankle. When in the hip joint, the normal flexion
up to 120 degrees, extension of 20 degrees, abduction of 50
degrees, internal and external rotation of 45 degrees will produce
variable axial, shear, and cyclic loads which the implant by design
will accommodate and endure as up to 6 times body weight,
consistent with a tire on a car that allows for cyclic loads
different when driving straight or turning corners. The implant
embodying features of the present invention provides more
physiologic motion and shock absorption within the joint and has
combined characteristics of anatomic design symmetry, balanced
rigidity with sufficient attachment connections to adjacent normal
structures, and durability that meet the needs of joint
reconstruction.
[0052] The opposing internal surfaces of the first and second walls
of the invention may either move together in synchrony or in
opposite directions from one another (e.g. the superior wall moving
medially in the hip and the inferior wall moving laterally).
Optionally, the implant may be fixed to a concave surface of the
joint (e.g., the acetabular hip cup) or to a convex surface of the
joint (e.g. the dorsal femoral head surface), to both, or to
neither (e.g., having an interference fit within the joint with an
expanding balloon or cushion that fills the existing space). The
implant may be inserted arthroscopically like a deflated balloon
and then inflated through a cannula into the ankle or hip (or other
joint structure) to act as a cushion or renewed interface for
painless and stable limb motion. When feasible joint capsular and
adjacent ligament tissue as well as bone will be left in place to
preserve the natural body, unless interfering with reconstructed
limb function.
[0053] The application of steam in addition to removing damaged
debris, can smooth out and reform the joint surface. The high
temperature of the steam tends to weld cracks or fissures which can
be present in the cartilage surface of a damaged joint. Smoothing
of joint surface cartilage with steam welds or seals existing
cracks or flaps in the cartilage, especially superficially as the
lamina splendors, which melt together to provide a white shiny
gliding joint surface. In cases where bone is exposed, the steam
can be used to stabilize the periphery of the defect in the joint
surface via capsulorrhaphy or joint tightening. Open mechanical and
chemical debridement may also be employed to prepare the surfaces
for the implant.
[0054] Once the implant is secured to the femoral head by means of
the skirt or tabs, an impregnated transfer medium or cell template
may be used, as described by Histogenics and Tygenix chondrocytes
delivery systems wherein the position of concentrated cells is
mechanically placed about the implant at areas of greatest
cartilage damage to promote regrowth, or as in Carticel wherein
watery cells are implanted beneath a periosteal membrane (a wall of
the implant serving as the membrane), prior to completion of the
inflation or expansion of the implant. At syringe or gauged device
with measured screw-home pressure is used to inflate the
implant.
[0055] Once the joint is ready to receive the implant, the deflated
implant is advanced through the diaphragm of a delivery cannula
(such as the Acufex from Smith & Nephew) and into the joint. It
can be inflated by the attached cannula using a common syringe,
inserting several cc's of filler material. Inserted contents and
locations of cell placements depend on areas of need and joint
size. In the hip implant several cc's of filler material and a
viscolubricant in the interior of the implant will allow
distension, cushioning, and gliding movements. Cell regeneration
agents are placed in the areas of greatest need.
[0056] Methods of living stem cell or chondrocyte placement depend
on the lesions and specific implant construct. Direct infusion into
the joint with completion of implant inflation will press the cells
into the hyaline surface, whereupon they attach within the first 24
hours. As a result, the patient should remain sedentary and the
joint where the implant is deployed, non-weight bearing for the
first day after surgery. Deeper osteochondral defects can be
treated by `hyper-perfusion of cells` via either 3-D cell transfer
templates, or microneedle injection as used in treatment of
diabetic patients for blood sugar testing and insulin/transdermal
drug delivery. The cannula attached to the implant may be sealed
and detached, or left in place for periodic aspiration of noxious
enzymes as for the Cox-1, Cox-2, and 5-Lox systems, followed by
reinsertion of activated substances including viscolubricants, or
even more cells.
[0057] Implants embodying features of the invention may be designed
for permanent or temporary deployment within a joint structure.
Moreover, the implant may be formed of suitable bioabsorbable
materials so that the implant may be absorbed within a particular
predetermined time frame. Suitable bioabsorbable materials include
polylactic acid, polyglycolic acid, polycaprolactone, copolymers,
blends and variants thereof. One present method of forming the
implant is to apply numerous layers of polymer such as ChronoFlex
AR in a solvent and evaporating the solvent after applying each
layer.
[0058] The skirting or fixation tabs of the present implant prevent
joint migration during use. This is in contradistinction with prior
solid polymer implants that tended toward dislocation and poor post
operative function.
[0059] While particular forms of the invention have been
illustrated and described herein, it will be apparent that various
modifications and improvements can be made to the invention. One
alternative implant construction involves the use of an upper
portion of the implant having a net-like construction and filled
with balls or ball bearing like elements that are larger than the
openings in the netting. The balls or ball bearing like elements
provide motion to the implant. The netting and ball bearing like
elements may include regeneration agents as previously discussed,
and the bearing construction may be directed toward favorable
implant movement balanced with content disbursement.
[0060] The invention is intended primarily for human use but may be
extended to mammalian use. To the extent not otherwise disclosed
herein, materials and structure may be of conventional design.
[0061] Moreover, individual features of embodiments of the
invention may be shown in some drawings and not in others, but
those skilled in the art will recognize that individual features of
one embodiment of the invention can be utilized in another
embodiment. Moreover, individual features of one embodiment may be
combined with any or all the features of another embodiment.
Accordingly, it is not intended that the invention be limited to
the specific embodiments illustrated. It is therefore intended that
this invention be defined by the scope of the appended claims as
broadly as the prior art will permit.
[0062] Terms such as "element", "member", "component", "device",
"means", "portion", "section", "steps" and words of similar import
when used herein shall not be construed as invoking the provisions
of 35 U.S.C .sctn. 112(6) unless the following claims expressly use
the terms "means for" or "step for" followed by a particular
function without reference to a specific structure or a specific
action. All patents and all patent applications referred to above
are hereby incorporated by reference in their entirety.
* * * * *