U.S. patent application number 12/010984 was filed with the patent office on 2008-06-05 for cartilage repair mixture containing allograft chondrocytes.
This patent application is currently assigned to Muscuoskeletal Transplant Foundation. Invention is credited to Arthur A. Gertzman, Katherine Ann Gomes Truncale.
Application Number | 20080133008 12/010984 |
Document ID | / |
Family ID | 40786705 |
Filed Date | 2008-06-05 |
United States Patent
Application |
20080133008 |
Kind Code |
A1 |
Truncale; Katherine Ann Gomes ;
et al. |
June 5, 2008 |
Cartilage repair mixture containing allograft chondrocytes
Abstract
The invention is directed toward a sterile cartilage defect
implant material comprising milled lyophilized allograft cartilage
pieces ranging from 0.01 mm to 1.0 mm in size in a bioabsorbable
carrier taken from a group consisting of sodium hyaluronate,
hyaluronic acid and its derivatives, gelatin, collagen, chitosan,
alginate, buffered PBS, Dextran or mixed polymers with allograft
chondrocytes added in an amount ranging from 2.5.times.10.sup.5 to
2.5.times.10.sup.7.
Inventors: |
Truncale; Katherine Ann Gomes;
(Hillsborough, NJ) ; Gertzman; Arthur A.;
(Flemington, NJ) |
Correspondence
Address: |
GREENBERG TRAURIG, LLP
200 PARK AVE., P.O. BOX 677
FLORHAM PARK
NJ
07932
US
|
Assignee: |
Muscuoskeletal Transplant
Foundation
|
Family ID: |
40786705 |
Appl. No.: |
12/010984 |
Filed: |
January 31, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11081103 |
Mar 16, 2005 |
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12010984 |
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Current U.S.
Class: |
623/14.12 ;
623/23.72 |
Current CPC
Class: |
A61F 2/30744 20130101;
A61F 2002/30225 20130101; A61L 27/3654 20130101; A61K 38/28
20130101; A61L 27/3683 20130101; A61F 2002/30764 20130101; A61L
27/3612 20130101; A61L 27/48 20130101; A61F 2002/30759 20130101;
A61B 17/00491 20130101; A61F 2210/0004 20130101; A61L 27/3834
20130101; A61F 2002/2817 20130101; A61F 2230/0069 20130101; A61L
27/58 20130101; A61L 2430/06 20130101; A61F 2310/00383 20130101;
A61F 2/3859 20130101; A61F 2002/30062 20130101; A61L 27/56
20130101; A61L 27/3817 20130101; A61F 2/28 20130101; A61L 27/3821
20130101; A61F 2/30756 20130101; A61F 2002/30224 20130101; A61K
35/32 20130101; A61L 27/24 20130101; A61F 2310/00365 20130101; A61L
27/3852 20130101; A61K 38/18 20130101; A61L 27/20 20130101; A61F
2/3094 20130101; A61K 35/28 20130101; A61F 2002/2835 20130101; A61K
38/18 20130101; A61K 2300/00 20130101; A61K 38/28 20130101; A61K
2300/00 20130101; A61K 35/28 20130101; A61K 2300/00 20130101; A61L
27/20 20130101; C08L 5/08 20130101 |
Class at
Publication: |
623/14.12 ;
623/23.72 |
International
Class: |
A61F 2/08 20060101
A61F002/08; A61F 2/02 20060101 A61F002/02 |
Claims
1. (canceled)
2. (canceled)
3. (canceled)
4. (canceled)
5. (canceled)
6. (canceled)
7. (canceled)
8. (canceled)
9. (canceled)
10. (canceled)
11. (canceled)
12. (canceled)
13. (canceled)
14. (canceled)
15. (canceled)
16. (canceled)
17. (canceled)
18. A method of placing a cartilage defect material in a cartilage
defect, said material comprising allograft articular cartilage
which has been lyophilized and mixed in a bioabsorbable carrier
comprising the steps of: (a) cutting patient tissue at a site of a
cartilage defect to remove the diseased area of cartilage; (b)
placing a mixture of milled allograft cartilage in a bioabsorbable
carrier in the area where cartilage has been removed; (c) adding
allograft chondrocytes taken from a human donor having an age
ranging from about 3 months to about 20 years to said mixture of
milled allograft cartilage in a bioabsorbable carrier; (d) sealing
a cover with a biological glue over the mixture of milled allograft
cartilage in a bioabsorbable carrier and added allograft
chondrocytes to contain the mixture in cartilage defect site for a
predetermined period of time to allow the formation of
cartilage.
19. A sterile cartilage defect material as claimed in claim 18
wherein said milled cartilage pieces have been lyophilized to have
a water content ranging from about 0.1% to about 8.0%.
20. A sterile cartilage repair material as claimed in claim 18
wherein said allograft chondrocytes are expanded growth
chondrocytes added in amount ranging from 2.5.times.10.sup.5 to
about 2.5.times.10.sup.7.
Description
RELATED APPLICATIONS
[0001] There is no related application.
FIELD OF INVENTION
[0002] The present invention is generally directed toward an
implant and is more specifically directed toward a paste or gel
implant material including allograft for a cartilage defect.
BACKGROUND OF THE INVENTION
[0003] Articular cartilage injury and degeneration present medical
problems to the general population which are addressed by
orthopedic surgeons. Every year in the United States, over 500,000
arthroplastic or joint repair procedures are performed. These
include approximately 125,000 total hip and 150,000 total knee
arthroplastics and over 41,000 open arthroscopic procedures to
repair cartilaginous defects of the knee.
[0004] In the knee joint, the articular cartilage tissue forms a
lining which faces the joint cavity on one side and is linked to
the subchondral bone plate by a narrow layer of calcified cartilage
tissue on the other. Articular cartilage (hyaline cartilage)
consists primarily of extracellular matrix with a sparse population
of chondrocytes distributed throughout the tissue. Articular
cartilage is composed of chondrocytes, type II collagen fibril
network, proteoglycans and water. Active chondrocytes are unique in
that they have a relatively low turnover rate and are sparsely
distributed within the surrounding matrix. The collagens give the
tissue its form and tensile strength and the interaction of
proteoglycans with water give the tissue its stiffness to
compression, resilience and durability. The hyaline cartilage
provides a low friction bearing surface over the bony parts of the
joint. If the lining becomes worn or damaged resulting in lesions,
joint movement may be painful or severely restricted. Whereas
damaged bone typically can regenerate successfully, hyaline
cartilage regeneration is quite limited because of it's limited
regenerative and reparative abilities.
[0005] Articular cartilage lesions generally do not heal, or heal
only partially under certain biological conditions due to the lack
of nerves, blood vessels and a lymphatic system. The limited
reparative capabilities of hyaline cartilage usually results in the
generation of repair tissue that lacks the structure and
biomechanical properties of normal cartilage. Generally, the
healing of the defect results in a fibrocartilaginous repair tissue
that lacks the structure and biomedical properties of hyaline
cartilage and degrades over the course of time. Articular cartilage
lesions are frequently associated with disability and with symptoms
such as joint pain, locking phenomena and reduced or disturbed
function. These lesions are difficult to treat because of the
distinctive structure and function of hyaline cartilage. Such
lesions are believed to progress to severe forms of osteoarthritis.
Osteoarthritis is the leading cause of disability and impairment in
middle-aged and older individuals, entailing significant economic,
social and psychological costs. Each year, osteoarthritis accounts
for as many as 39 million physician visits and more than 500,000
hospitalizations. By the year 2020, arthritis is expected to affect
almost 60 million persons in the United States and to limit the
activity of 11.6 million persons.
[0006] There are many current therapeutic methods being used. None
of these therapies has resulted in the successful regeneration of
hyaline-like tissue that withstands normal joint loading and
activity over prolonged periods. Currently, the techniques most
widely utilized clinically for cartilage defects and degeneration
are not articular cartilage substitution procedures, but rather
lavage, arthroscopic debridement, and repair stimulation. The
direct transplantation of cells or tissue into a defect and the
replacement of the defect with biologic or synthetic substitutions
presently accounts for only a small percentage of surgical
interventions. The optimum surgical goal is to replace the defects
with cartilage-like substitutes so as to provide pain relief,
reduce effusions and inflammation, restore function, reduce
disability and postpone or alleviate the need for prosthetic
replacement.
[0007] Lavage and arthroscopic debridement involve irrigation of
the joint with solutions of sodium chloride, Ringer or Ringer and
lactate. The temporary pain relief is believed to result from
removing degenerative cartilage debris, proteolytic enzymes and
inflammatory mediators. These techniques provide temporary pain
relief, but have little or no potential for further healing.
[0008] Repair stimulation is conducted by means of drilling,
abrasion arthroplasty or microfracture. Penetration into the
subchondral bone induces bleeding and fibrin clot formation which
promotes initial repair, however, the tissue formed is fibrous in
nature and not durable. Pain relief is temporary as the tissue
exhibits degeneration, loss of resilience, stiffness and wear
characteristics over time.
[0009] The periosteum and perichondrium have been shown to contain
mesenchymal progenitor cells capable of differentiation and
proliferation. They have been used as grafts in both animal and
human models to repair articular defects. Few patients over 40
years of age have obtained good clinical results, which most likely
reflects the decreasing population of osteochondral progenitor
cells with increasing age. There have also been problems with
adhesion and stability of the grafts, which result in their
displacement or loss from the repair site.
[0010] Transplantation of autologous cells grown in culture
provides another method of introducing a new cell population into
chondral and osteochondral defects. Autologous cells are used to
preclude immune response. Carticel.RTM. is a commercial process to
culture a patient's own cartilage cells for use in the repair of
cartilage defects in the femoral condyle marketed by Genzyme
Biosurgery in the United States and Europe. The procedure uses
arthroscopy to take a biopsy from a healthy, less loaded area of
articular cartilage. Enzymatic digestion of the harvested tissue
releases the cells that are sent to a laboratory where they are
grown for a period ranging from 2-5 weeks. Once cultivated, the
cells are injected during a more open and extensive knee procedure
into areas of defective cartilage where it is hoped that they will
facilitate the repair of damaged tissue. An autologous periosteal
flap with cambium layer is used to seal the transplanted cells in
place and act as a mechanical barrier. Fibrin glue is used to seal
the edges of the flap. This technique preserves the subchondral
bone plate and has reported a high success rate. Proponents of this
procedure report that it produces satisfactory results in a number
of patients, including the ability to return to demanding physical
activities and that biopsy specimens of the tissue in the graft
sites show hyaline-like cartilage repair. More work is needed to
assess the function and durability of the new tissue and determine
whether it improves joint function and delays or prevents joint
degeneration. As with the perichondrial graft, patient/donor age
may compromise the success of this procedure as chondrocyte
population decreases with increasing age. Disadvantages to this
procedure include the need for two separate surgical procedures,
potential damage to surrounding cartilage when the periosteal patch
is sutured in place, the requirement of demanding microsurgical
techniques, and the expensive cost of the procedure which is
currently not covered by insurance.
[0011] Osteochondral transplantation or mosaicplasty involves
excising all injured or unstable tissue from the articular defect
and creating cylindrical holes in the base of the defect and
underlying bone. These holes are filled with autologous cylindrical
plugs of healthy cartilage and bone in a mosaic fashion. The
osteochondral plugs are harvested from a lower weight-bearing area
of lesser importance in the same joint. This technique, shown in
Prior Art FIG. 2, can be performed as arthroscopic or open
procedures. Reports of results of osteochondral plug autografts in
a small number of patients indicate that they decrease pain and
improve joint function, however, long-term results have not been
reported. Factors that can compromise the results include donor
site morbidity, effects of joint incongruity on the opposing
surface of the donor site, damage to the chondrocytes at the
articular margins of the donor and recipient sites during
preparation and implantation, and collapse or settling of the graft
over time. The limited availability of sites for harvest of
osteochondral autografts restricts the use of this approach to
treatment of relatively small articular defects and the healing of
the chondral portion of the autograft to the adjacent articular
cartilage remains a concern.
[0012] Transplantation of large allografts of bone and overlying
articular cartilage is another treatment option that involves a
greater area than is suitable for autologous cylindrical plugs, as
well as for a non-contained defect. The advantages of osteochondral
allografts are the potential to restore the anatomic contour of the
joint, lack of morbidity related to graft harvesting, greater
availability than autografts and the ability to prepare allografts
in any size to reconstruct large defects. Clinical experience with
fresh and frozen osteochondral allografts shows that these grafts
can decrease joint pain, and that the osseous portion of an
allograft can heal to the host bone and the chondral portion can
function as an articular surface. Drawbacks associated with this
methodology in the clinical situation include the scarcity of fresh
donor material and problems connected with the handling and storage
of frozen tissue. Fresh allografts carry the risk of immune
response or disease transmission. Musculoskeletal Transplant
Foundation (MTF) has preserved fresh allografts in a media that
maintains a cell viability of 50% for 35 days for use as implants.
Frozen allografts lack cell viability and have shown a decreased
amount of proteoglycan content which contribute to deterioration of
the tissue.
[0013] A number of patents in the prior art show the use of bone
putty, pastes or gels to fill bone defects. U.S. Pat. No. 5,290,558
issued Mar. 1, 1994 discloses a flowable demineralized bone powder
composition using an osteogenic bone powder with large particle
size ranging from about 0.1 to about 1.2 cm. mixed with a low
molecular weight polyhydroxy compound possessing from 2 to about 18
carbons including a number of classes of different compounds such
as monosaccharides, disaccharides, water dispersible
oligosaccharides and polysaccharides.
[0014] A bone gel is disclosed in the U.S. Pat. No. 5,073,373
issued Dec. 17, 1991. Bone lamellae in the shape of threads or
filaments retaining low molecular weight glycerol carrier are
disclosed in U.S. Pat. Nos. 5,314,476 issued May 24, 1994 and
5,507,813 issued Apr. 16, 1996 and the tissue forms described in
these patents are known commercially as the GRAFTON.RTM. Putty and
Flex, respectively.
[0015] U.S. Pat. No. 5,356,629 issued Oct. 18, 1994 discloses
making a rigid gel in the nature of a bone cement to fill defects
in bone by mixing biocompatible particles, preferably
polymethylmethacrylate coated with polyhydroxyethylmethacrylate in
a matrix selected from a group which lists hyaluronic acid to
obtain a molded semi-solid mass which can be suitably worked for
implantation into bone. The hyaluronic acid can also be utilized in
monomeric form or in polymeric form preferably having a molecular
weight not greater than about one million Daltons. It is noted that
the nonbioabsorbable material which can be used to form the
biocompatible particles can be derived from xenograft bone,
homologous bone, autogenous bone as well as other materials. The
bioactive substance can also be an osteogenic agent such as
demineralized bone powder, morselized cancellous bone, aspirated
bone marrow and other autogenous bone sources. The average size of
the particles employed is preferably about 0.1 to about 3.0 mm,
more preferably about 0.2 to about 1.5 mm, and most preferably
about 0.3 to about 1.0 mm. It is inferentially mentioned but not
taught that particles having average sizes of about 7,000 to 8,000
microns, or even as small as about 100 to 700 microns can be
used.
[0016] U.S. Pat. No. 4,172,128 issued Oct. 23, 1979 discloses a
demineralized bone material mixed with a carrier to reconstruct
tooth or bone material by adding a mucopolysaccharide to a
mineralized bone colloidal material. The composition is formed from
a demineralized coarsely ground bone material, which may be derived
from human bones and teeth, dissolved in a solvent forming a
colloidal solution to which is added a physiologically inert
polyhydroxy compound such as mucopolysaccharide or polyuronic acid
in an amount which causes orientation when hydrogen ions or
polyvalent metal ions are added to form a gel. The gel will be
flowable at elevated temperatures above 35.degree. C. and will
solidify when brought down to body temperature. Example 25 of the
patent notes that mucopolysaccharides produce pronounced ionotropic
effects and that hyaluronic acid is particularly responsible for
spatial cross-linking.
[0017] U.S. Pat. No. 6,030,635 issued Feb. 29, 2000 and U.S. Pat.
No. 6,437,018 issued Aug. 20, 2002 are directed toward a malleable
bone putty and a flowable gel composition for application to a bone
defect site to promote new bone growth at the site which utilize a
new bone growth inducing compound of demineralized lyophilized
allograft bone powder. The bone powder has a particle size ranging
from about 100 to about 850 microns and is mixed in a high
molecular weight hydrogel carrier which contains a sodium phosphate
saline buffer.
[0018] The use of implants for cartilage defects is much more
limited. Aside from the fresh allograft implants and autologous
implants, U.S. Pat. No. 6,110,209 issued Nov. 5, 1998 shows the use
an autologous articular cartilage cancellous bone paste to fill
arthritic defects. The surgical technique is arthroscopic and
includes debriding (shaving away loose or fragmented articular
cartilage), followed by morselizing the base of the arthritic
defect with an awl until bleeding occurs. An osteochondral graft is
then harvested from the inner rim of the intercondylar notch using
a trephine. The graft is then morselized in a bone graft crusher,
mixing the articular cartilage with the cancellous bone. The paste
is then pushed into the defect and secured by the adhesive
properties of the bleeding bone. The paste can also be mixed with a
cartilage stimulating factor, a plurality of cells, or a biological
glue. All patients are kept non-weight bearing for four weeks and
used a continuous passive motion machine for six hours each night.
Histologic appearance of the biopsies have mainly shown a mixture
of fibrocartilage with hyaline cartilage. Concerns associated with
this method are harvest site morbidity and availability, similar to
the mosaicplasty method.
SUMMARY OF THE INVENTION
[0019] A cartilage implant material in paste or gel form for
repairing articular cartilage defects is composed of milled
allograft cartilage pieces and allograft chondrocytes in a
bioabsorbable carrier. Allograft chondrocytes occurring in hyaline
cartilage from a neonate (age 3 months) to young adult 20 years of
age are added to the implant material and the cartilage pieces are
taken from the same donor. Additives may be applied to the mixture
in order to increase chondrocyte migration and proliferation. The
implant material can support the addition of a variety of
chondrogenic stimulating factors including, but not limited to
growth factors (FGF-2, FGF-5, IGF-1, TGF-.beta., BMP-2, BMP-7,
PDGF, VEGF), human allogenic or autologous bone marrow cells, stem
cells, demineralized bone matrix, insulin, insulin-like growth
factor-1, transforming growth factor-B, interleukin-1 receptor
antagonist, hepatocyte growth factor, platelet-derived growth
factor, Indian hedgehog and parathyroid hormone-related peptide or
bioactive glue.
[0020] The implant material is placed in the lesion area optionally
with a plug of bone and hyaline cartilage cap and may be sealed
with a periosteum cap.
[0021] It is an object of the invention to provide an allograft
implant material for joints which provides pain relief, restores
normal function and will postpone or alleviate the need for
prosthetic replacement.
[0022] It is also an object of the invention to provide a cartilage
repair implant material which is easily placed in a defect area by
the surgeon using an arthroscopic, minimally invasive
technique.
[0023] It is further an object of the invention to provide an
allograft implant material procedure which is applicable for both
partial and full thickness lesions.
[0024] It is yet another object of the invention to provide an
allograft implant material which facilitates growth of hyaline
cartilage through the use of allograft chondrocytes.
[0025] It is an additional object of the invention to provide
implant paste and gel material formulations that satisfy surgical
requirements and are made from donated human available allograft
tissue, some of which would otherwise be considered waste and
thrown away.
[0026] These and other objects, advantages, and novel features of
the present invention will become apparent when considered with the
teachings contained in the detailed disclosure along with the
accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 shows the anatomy of a knee joint with a lesion;
[0028] FIG. 2 shows a schematic mosaicplasty as known in the prior
art; and
[0029] FIG. 3 shows a schematic perspective view of cartilage
defect material placed in a defect site with an exploded periosteum
cap.
DESCRIPTION OF THE INVENTION
[0030] The terms "tissue" is used in the general sense herein to
mean any transplantable or implantable tissue, the survivability of
which is improved by the methods described herein upon
implantation. In particular, the overall durability and longevity
of the implant are improved, and host-immune system mediated
responses, are substantially eliminated.
[0031] The terms "transplant" and "implant" are used interchangably
to refer to tissue, material or cells (xenogeneic or allogeneic)
which may be introduced into the body of a patient to replace or
supplement the structure or function of the endogenous tissue.
[0032] The terms "autologous" and "autograft" refer to tissue or
cells which originate with or are derived from the recipient,
whereas the terms "allogeneic" and "allograft" refer to cells and
tissue which originate with or are derived from a donor of the same
species as the recipient. The terms "xenogeneic" and "xenograft"
refer to cells or tissue which originates with or is derived from a
species other than that of the recipient.
[0033] The term "gel" refers to a mixture of minced or milled
pretreated allograft cartilage in a biocomposite carrier having a
viscosity which is less than and is less rigid than a mixture of
minced or milled pretreated allograft cartilage in a biocompatible
carrier referred to by the terms "putty" or "paste" and contains
less cartilage by weight than putty or paste.
[0034] The present invention is directed towards a cartilage repair
material and method of treatment. The preferred embodiment and best
mode of the invention is shown in FIG. 3. In the production of the
invention, allograft hyaline cartilage is preferably taken from the
same age donors as listed below, lyophilized reducing its water
content and milled for ease in application.
[0035] After washes with sterile de-ionized (DI) water, the
cartilage material was frozen at -20.degree. to -100.degree. C.
preferably -70.degree. C. and lyophilized to reduce the water
content within the range of about 0.1% to about 8.0%. The cartilage
is frozen with liquid nitrogen and milled into particles.
[0036] A lesion or defect is removed by cutting a bore 50 or
trimming a lesion in the implant area 100 and filling the bore 50
or lesion area with a milled cartilage mixture 20 of paste or gel
and allograft chondrocytes together with a biological carrier such
as hyaluronic acid and its derivatives, gelatin, collagen,
chitosan, alginate, buffered PBS, Dextran, or polymers and one or
more additives namely chondrogenic stimulating factors including,
but not limited to growth factors (FGF-2, FGF-5, IGF-1, TGF-.beta.,
BMP-2, BMP-7, PDGF, VEGF), human allogenic cells, human allogenic
or autologous bone marrow cells, human allogenic or autologous stem
cells, demineralized bone matrix, insulin, insulin-like growth
factor-1, interleukin-1 receptor antagonist, hepatocyte growth
factor, platelet-derived growth factor, Indian hedgehog and
parathyroid hormone-related peptide. The chondrocytes are
preferably taken from human donors ranging from the ages of
neonates (3 months) to young adults age 20. The most preferred
human donors range between the ages of 3 months to 12 years. The
chondrocytes can be expanded to increase the numbers or taken
directly from the human donor. The preferred amount of chondrocytes
applied to the paste or gel range in number from 2.5.times.10.sup.5
to 2.5.times.10.sup.7 and are carried in about 1.0 to 10.0 cc of
fluid contained in a syringe. Most preferably, the amount of
chondrocytes is about 2.5.times.10.sup.6. The chondrocytes may be
taken directly from the donor and expended by known means to
increase the chondrocytes population. Chondrocytes do not cause
immune response when used in the present mixture.
[0037] Suitable organic glue material can be used to keep the
viscous cartilage mixture 20 and any associated plug fixed in place
in the implant area or to affix a periosteal cap 30 in place over
the surrounding hyaline cartilage area 100. Suitable organic glue
material can be found commercially, such as for example;
TISSEEL.RTM. or TISSUCOL.RTM. (fibrin based adhesive; Immuno AG,
Austria), Adhesive Protein (Sigma Chemical, USA), and Dow Corning
Medical Adhesive B (Dow Corning, USA).
EXAMPLE 1
[0038] A matrix of minced cartilage putty consisting of minced or
milled allograft articular cartilage which has been lyophilized so
that its water content ranges from 0.1% to 8.0% with a cartilage
content ranging from 25% to 50% by weight is mixed with a carrier
of sodium hyaluronate solution (HA) (molecular weight ranging from
7.0.times.10.sup.5 to 1.2.times.10.sup.6) or any other
bioabsorbable carrier such as hyaluronic acid and its derivatives,
gelatin, collagen, chitosan, alginate, buffered PBS, Dextran, or
polymers, the carrier ranging from 50% to 75% by weight. The
cartilage is milled to a size ranging from 0.01 mm to 1 mm. In gel
form, the minced cartilage which has been lyophilized so that its
water content ranges from 0.1% to 8.0% ranging from 15% to 30% by
weight and the carrier ranges from 70% to 85% by weight. The
particle size of the cartilage when milled is less than or equal to
1 mm dry in the previously stated range. The cartilage pieces can
be processed to varying particle sizes and the HA or other carrier
can have different viscosities depending on the desired consistency
of the putty or paste. Allograft chondrocytes in an amount ranging
from 2.5.times.10.sup.5 to 2.5.times.10.sup.7 taken from a human
donor ranging from 3 months to 20 years of age are inserted into
the mixed putty matrix. This cartilage matrix can be deposited into
the cartilage defect arthroscopically and fit into the defect where
it is held in place by it's own viscosity, mixed with fibrin glue
or covered with a periosteal or perichondrial flap, then sealed
with biological glue. This matrix can support the previously
mentioned chondrogenic factors.
EXAMPLE 2
[0039] A matrix of minced cartilage putty consisting of minced or
milled allograft cartilage taken from the same human donor as the
chondrocytes noted below which has been lyophilized so that its
water content ranges from 0.1% to 8.0% ranging from 25% to 50% by
weight is mixed with a carrier of sodium hyaluronate solution (HA)
(7.0.times.10.sup.5 to 1.2.times.10.sup.6) or any other
bioabsorbable carrier such as hyaluronic acid and its derivatives,
gelatin, collagen, chitosan, alginate, buffered PBS, Dextran, or
polymers ranging from 50% to 75% by weight. In a gel form, the
minced cartilage which has been lyophilized so that its water
content ranges from 0.01% to 8.0% ranging from 15% to 30% by weight
and the carrier ranges from 70% to 85% by weight. The particle size
of the cartilage is less than or equal to 1 mm dry ranging from
0.01 mm to 1 mm. The cartilage pieces can be processed to varying
particle sizes and the HA or carrier can have different viscosities
depending on the desired consistency of the putty or paste.
Allograft chondrocytes which have been grown or expanded from
chondrocytes taken from a human donor ranging from 3 months to 20
years of age in an amount ranging from about 2.5.times.10.sup.5 to
2.5.times.10.sup.7 are inserted by syringe into the matrix before,
during or after deposit of the cartilage matrix into the defect
area. This composite material can be injected into the cartilage
defect arthroscopically and fit into the defect where it is held in
place by it's own viscosity, or covered with a periosteal or
perichondrial flap, then sealed with biological glue. As with the
first matrix, this matrix can support the previously mentioned
chondrogenic factors.
[0040] The operation of placing the cartilage composition in a
cartilage defect, comprises (a) cutting a patient's tissue at a
site of a cartilage defect to remove the diseased area of
cartilage; (b) placing a mixture of milled lyophilized allograft
cartilage in a bioabsorbable carrier and allograft chondrocytes in
the defect area; and (c) placing a periosteal cover over the
mixture of the inserted milled allograft cartilage in a
bioabsorbable carrier to contain the mixture in the defect area for
a predetermined period of time to promote cartilage growth at the
defect site. Alternate steps include the addition of growth
factors, bone marrow cells and stem cells.
[0041] The principles, preferred embodiments and modes of operation
of the present invention have been described in the foregoing
specification. However, the invention should not be construed as
limited to the particular embodiments which have been described
above. Instead, the embodiments described here should be regarded
as illustrative rather than restrictive. Variations and changes may
be made by others without departing from the scope of the present
invention as defined by the following claims:
* * * * *