CA2675170C

CA2675170C - Two piece cancellous construct for cartilage repair

Info

Publication number: CA2675170C
Application number: CA2675170A
Authority: CA
Inventors: Eric J. Semler; Katherine G. Truncale; Alex B. Callahan; Judith I. Yannariello-Brown
Original assignee: Musculoskeletal Transplant Foundation
Current assignee: Musculoskeletal Transplant Foundation
Priority date: 2007-01-24
Filing date: 2008-01-23
Publication date: 2014-09-30
Anticipated expiration: 2028-01-23
Also published as: CA2675170A1; US8906110B2; US7837740B2; WO2008106254A2; WO2008106254A3; US20110224797A1; EP2162094A2; US20080255676A1

Abstract

The invention is directed toward a cartilage repair assembly comprising a shaped allograft two piece construct (20) with a demineralized cancellous cap (30) and a mineralized cylindrical base member (22) defining a blind bore (23) wrth a through going transverse bore (28) intersecting the blind bore (23). The demineralized cancellous cap (30) has a cylindrical top portion (32) and a smaller diameter cylindrical stem (36) extending away from the top portion (32) which fits into the blind bore (23) of the mineralized base member (22). The cap stem (36) defines a transverse through going bore (37) which is aligned with the through going bore (28) of the base member (22) to receive a cylindrical cortical pin (40) holding the cap (30) within the base member (22). The shaped structure (20) is dimensioned to fit in a drilled bore in a cartilage delect area so that the assembly engages the side wall of the drilled bore in an interference fit.

Description

TWO PrfiCKCANCELLOUS CONSTRUCT MR
CAT.AGJ REP NER
B A C KGRO UNDOPT LIE INVENTION
Field of Invention Pre.sePt in,Natipo is generally directed tomird Lin all graft cartilage.
repair implam and is more specifically directed toward a two piece allograft cancellous bone implant having a &mineralized catieelious bone cap member zmd a mineralized r partial ly demineealized cancellous bone base impanbcr, both pieces being held tog:ether with ;au allograft bone pin, The construct ia shaped 1i:if an interference tit inwlantation in a shoulder., knee, hip, or anklejoint. 'The base member.
is provided with an axially posoned blind bore and a plurality of ,:zuialler dianieto; through ,k;oing bores which allow 'transport Of cellular materials throughout the iinplant site to stimulate cartilage grout 2. Deseriktion of the Prior Art Articular kzatilagc hijary and degeneration present medical pl-oblems to the genetat population whichiseonstantly addresspd by orthopedic surgeons. tvery year in'the Stges, OVCf 500,000 arthroplastic or joint repair procedures aroper.fortned. These include approximatOy 1.25A0 total hip and 150,000 tOtal knee attlithplasticsandoVer 41.,000openarthroscopic pmcedures to repair cartilaginous dekets of-the ktim.
In the knee joint, the articular cartilage= tissue tbroiS a lining µvhich -fixes. tho joint cavity- OP.
Otx, side and is :linked to -the subehondnd bone plate by a narrow layer Ocalcified cartilage tissue on the other. Articular cartilage (hyaline cartilage): cctrsts prhnarily f extracellular matrix with a spaise .poptilation of chondrocytcs distributed. throughout the .tissue.
Articular cartilage is composei.
ofehondrocytes:, typell collagen fibril Meshwork proteoglycans and water.
Active chottdrocytts are unique in that they have a- relatively low turnover rate and are sparsely distributed within the surroundingmattix. The cOlingertit give the fissile its formand.
tensileatmgtb. zind the interattion(tf proteoglycans with. water give the tissue its stiffness to. compression, msilience and durability, The.
hyaline cartilage provi&sa low friction bearing surface over the hohyparts a the Joint, ethe becomes worn or danuiged resulting in lesions, joint. mowtnent may be paiaftdor seven:4y restricted..
Whereas darnagedbo typically can regenerate- successfully, hyaline cartilage regeneration is-quite limited because of it's limited .regenerative and reitarati.ve A.rticuiar cartilage leSims. generally do not heal, or heal only partially under -certain. biological .
conditions- due to the lac,k of nerves, blood vessels and a lyntithatic system. The limited reparative capabilities of hyaline cartilage ustially results itt the .generation .of repair tissue that- lae.ks the structure and. biontochaniezil ploperties of normal cartilage. Generally, the healing of the Ilefec-t results -in a .fibrocanilaghtons repair tisane: that lacks the -structure arid biomedical properties of hyaline c.artilage and -degrades. over the course of time. Articular cartilage lesions are frequently as:sociated with digability andWith symptonis Stich as joint pain, locking phenomena and reduced or disturbed function. These lesions are diffictilt to treat because of the distinctive structure and function of hyaline cartilage. Such lesionsare believed to ptOgreSs to Severe forms of osteoarthritis.
Osteoarth:ritis is the leading cause of disability and impairment in middle-aged and. older individuals, entailing significanteconornic, setial and psychologiCal coats. Each year;osteoarthritis a&ountsibr as many as 39 million :physician visits and more than 500,000 hospitalizations. y the year 2020, arthritis is expected to affect almost 60 million Ian-sons in the 13nited States and to limit the -activity of 11 .6 Million ..persons.

Therearoinany current therapeutic methods being used. None of these therapies has iv:suited in the sucmssful regeneration .of hyaline-like tissue-that withstands nortnal-joint loading and aCtiVity river .ptolortg ris.Cunsently, the techniques most widely utilized clinical}, for cartilage.
defects and degeneratiort are not articular cartilage -stibstitution proem:huts, but Mther lawny, atthroscopie debridement, and repair stinrulation.. The direct transplaatation of cells or tissue into a..
de:fect and the teplamment ofthe -defect withitiologicor synthetic.
substitutions presently accounts for only a small percentage.. of surgical .interventions. lite optimum sinical. goal is to replace the defsmts with carding-like substitutes so as -to provide painrelief, mime eilizions and inflammation, restore. function, reduce disability and postpotv or alleviate the need COT
prosthetic replacement Layne andarthrt)scopic debtidc.ment involve inigation of the joint- with: so lutions of sudiurn chlori4.1e.. Ringer or Rinpr and lactate. The tempora:ry pain relief is believed to result from removing degenerative cartilage debris, p.roicolytic enzytnes and inflammatory mediators.. These techniques providetemporary pain relief; hat have little or no potential for further healing, kep.air stimulation:is conducted by .meatut of drilling: 1,1brasion.
artluoplasty or microfracture.
Penetration into the subchondral. bone induces bleeding and :fibrin clot fimpation which promotes initial repair., however, the tissue formixt is fibrous- in nature and. not durable: Pain. relief is temporary as the tissue exhibits-degeneration, loss of resilienee, stifThess and wear chantctetiStics over time.
The periosteum and perichortdrium have- been shown to contain mesenchyrnal pmgeriitor cells capable of differentiation and proliferation. They have ball tised .as grafisin both animal and human m.odels to repair articular deka& Few patients over 40 years of ago obtain good clinical resat% which most lik.ely .reflect the decreasing 1)opulation of -osteochondral -progenitercells with increasing age. Th,ere have also been problemswitb adhesion and t tability of thegrallsõ which result intheir displacernent or loss from the repair site.
Transplantation areas garyva in. culture provides .another rnethed of introducing a Ile* cell population into ebondrai and osteochondrat do.fects. CART:len-14o a.
commercial process to culture a paient's on cartilage cells for use in the repair of cartilage defects in the femoral condyle marketed:by Cieuzyme Biosurgery f.rì tholinited States and Europe. The procedure uses arthroseopy to take a biopsy tiorn a healthy,. less loaded area of articular cartilage, Enzymatic .digestion of the harvested tiSsue releases the cells that .are sent to a laboratory whete. they are grown for a period ranging -from 2-5- .veeks. Once cultivated, the cells are injected during a mo.re open. and extensive knee procedure into areas of defective cartilage wit= it is hoped that they will. facilitate themair of damagethissue, antologous periosteal flap with &cambium layer is used to.seal the transplanted mils in phIce and act asa mechanical barrier. Fibrin glue is us,al to.sealthe edges of the flap. -.This.
tk....chnique preserves.t subchondral bone plate and ha,s reported a high success:lute.. Proponents of th iS procedure report that it produces satisfactory re:sults, including theability to return to -demanding physical activities, in motethan 90% of patients and those hiopsyspecirmls of the tissue in the graft sites show. byaline-like cartilage-repair. More work is needed to assess the function and dumbility of the new tissue and determine whether it. improves joint function and delays or preents joint.
degeneration. As- with the periehoudrial graft., patient/donor age may communise the suctims of this procedure- asehondrocyte population decrease.s with Inc -teasing age.
Disadvantages to this procedure include the need for CO Separate surgical procedures, .potentiai damage to 11.1Tounding ottrtiltigte when. the pariostetd patehì suturr....d in place, the: requirement of demanding mieresurgical techniqu.es, and the expensive cost Of the, procedure which is currently not covered by: insurance.
Osteoehtuulral transplantation or muiaicplasty involves excising all. in:plied or unstabletiasue lion) the articular defect and creating cylindrical holes in the base of the defect and. underlying.hone.
These holes are filled with autologous cylindrical- plugs t4healthyeartitage aod lx)nehl. a MOSAIC
fashion, The osteoehoralral . plugs are rvested from a over weight-bearing area of lesser import-mot:in the same joint.. This technique, shown in P.rior Art Figure .2, ean he performed as arthroscopio or open procedures. Reports of results of oateochondral plug autografls in a small numbers of patients indicate thatthey decreasepain and improve joint function,. however, long-temi results have nottx.1,en reported. Factors that can compromise the results include donor site morbidity, effects ofjoint incongruity -on the -opposing siltfitiV Of tht..:donor site, damage to thechondroeytes at the articular- m.argins of the donor and nxipient sites (luting preparation and implantation, and collapse or st:zrtling of the graft: over time.- The.. Ihnited availability of sites for harvest -of osteclebondral autografts restricts the use of thisapproach to treatment of rdati rely small articular defects and the healing Of the chondral portion of the autograft to the -adjacent articular cartilage remains a concern:

Transplantation of lar.ge allogmfis 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 allogratts are the..pok--ntial to restore the .anatomic corttour of the Joint, lack of morbidity related to graft harvesting,. greater availability than autogratls and the ability to prepare allogratts in any size to r.econStruet large de.fects.
experience with, fresh and..froz.en osteochondralallografts shows that these g,:ralis can decreasejoint pain, and that .the ()woo portion of an allograft Can heal to the host bone and the chondral portion -earl functioii as an articular surface. Drawbacks associated -with this methodology in. the:clinical situation include the .scarcity afresh donor material:and problems conneeted With the handling and:
storage of frozen tissue. Fresh allografts carry the risk ofimmune response or disease transmission.
Muscaloskeletal Traavlant Foundation (MIT) has prserved fresh allografts in a media that 1110intains :a ceviability-of 50% tbr 35 clay.s -for tise.as implants, frozen auografts lack eell viability and have shown-a decreased amounto.f proteoglycan content which contlibute to dettajoration of the tissue_ A number of 1:lnited Srates Patents have been specifically directed towards.
bone plugs which a.re....implanted into a bone defect. .Examples of such hone plu.gs are U.S.
Patent. Number 4,950,296 issued A Ugt#Sii 1990 which discloses a hone graft device comtvising a cortical she having a selecwl outer Shape and a cavity tbrined therein. fir receiving .a.caneellons plug, winch is fitted into the cavity in a manner to expose at least one surfcn J.S.Patent 'Number 6,039,762 issued Match.
2 I. 2()00 discloses a. cylindrizal shell. -with an interior body of tie activated hone. material and Patent Number 6,398,81 issued june 4 ,2002 directed toward a bme. spacer which has a cylindrical cortical -bone plug with an internal through going bore designed to hold -a nforcing member. 1.1.S.
Patent Number 6,$81211 issued :May 7, 2002 discloses an. invertelmtl implant having a substantially cylindrical bad y with. a through going bore dimensioned. to receive bone -growth S. Patent Nutnber 6,379,385 issued April 30, 2002 disclOsts an implant base body of spongious bone material -into. Whic:h a load carrying:.support element is embedded,. The support element can take the shape of a diagonal cross or a plurality of cylindri cal pins. See also, U.S.: Patent Number 6,294,187 issued September 25, 2001 svhich is dimted-to a load hearing otik.oirntilant made of commssed bone particles' in the -form of a cylinder. The cylinder is provided with a plurality of through going bcires to promote bilmId Om through the ostgoimpla.rit or.- to luild ademineralized bone and.i...4yrol paste mixture, Patent Number -6,096,081 issued August 1, 2000 sholvs a bone dowel with a cortical erid. cap or caps at both..ends, a brittle cancel:Iota body and. a through going bore.-While these implants have been used for bone tissue meneration, e same- will not work to repair Cartilage areas due to the osteoinductivenature of the bone -which eauses bone growth.
The use of implants for cartilage defec ts. is much more limited. Aside finm the :fresh allogratl.
iinplants and aide/nous. implants, Patent :Ni.iniber 6,110,209 issued-November 1998 showS
the use an map jogo.tis articular cartilage cancellotts bone pa.ste to: fill arthritic. defects. The surgical.
technique -is arthroscopic and includes debriding (shaving aWay lose orfit lamented artiettlar cartilage), followed. by morselizing the ..base of the arthritic defect. with an awl until bleeding occurs, An osteoahondtal grafi it- then harvested from thc inner rint a the intercondylar notch using a trephine. The graft is then morselized in a bone graft .crusher, mixinE,..,.;
the firticular cartilage with the cancellous bone. -:Tliepaste thenpustaxl into the defect.and aermred b the adhesive properties -of the bleeding bone, 'M.', paste cart r.dso be mixed with a cartilage stimulating factor, a plurality or cells,. or a biological glue. All patients. are kept. non-weight bearing fOr-four weeks and used a continuous passive motiort.machine for six hours each night.
Histologic.appearance of the biopsies.
has mainly shown a mixture of fibrocartilage with:hyaline cartilage. ConeernS
aS:SOCiated with this method are harvest site morbidity and availability, similar to the mot.irricplasty method, 1.I.S..PatentNtunber 6,379õ367 issued April 3O 2002 discloses a plug with a base menthrane, a control plug, and atop membrane-which overlies the surface -of the cartilage covering the defecti ve area fthe joint.
SUMMARY OF THE INVENTION
A cartilage repair a:Wm:ft-construct implant comprising a two picsx allogmft hone. construct with a mineraliztx1 erclatcancellms bone base. member and a. dernineraliza/
and non-ostepinducti ve cancellous bone cap .member mounted ìra a blind bore cnt in the. cancellous bone base member, the two .mernbers being- held together by an. allograft bone pin. The tv.,,opit..ve construct is used for replacing articular cartilage defixts and is plac0 in a bore. which .has= been cut into the patient to remove the lesion defect area. The bone base member has an axially aligned blind bore, a transverse through going bore which intersects the blind bore and has a plurality of through going bores which run parallel to the axis of the cylindrical bone base member. The cap member has a stem which fits into the blind bore of the base member with the stem defining a transverse through going bore. The base surface of the cap member body overlies the upper surface of the cylindrical base member with the stem bore and the base member transverse bore being aligned to receive a cortical pin. Additives may be applied to the internal bores, blind bore or the cap member of the construct in order to increase or accelerate cartilaginous or bony tissue formation.
Each allograft construct can support the addition of a variety of chondrogenic stimulating factors including, but not limited to morselized allogeneic cartilage, growth factors (FGF-2, FGF-5, IGF-1, TGF-13, BMP-2, BMP-7, PDGF, VEGF), human allogenic or autologous chondrocytes, 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.
In one aspect, there is provided a construct for cartilage repair, comprising:
a cap member formed from bone, said cap member including a stem having a longitudinal axis, which defines an axial direction, and a radial bore extending generally transversely into said stem from an exterior surface thereof, and a top section attached to one end of said stem and extending radially outward therefrom, said top section being substantially demineralized, whereby said top section has an elastic quality; a base member at least partially formed from mineralized bone, said base member including a blind bore extending in said axial direction from one end of said base member toward an opposite end thereof and sized and shaped so as to receive said stem of said cap member, said blind bore having a bottom surface intermediate said one end of said base member and said opposite end of said base member, said one end of said base member including an annular surface surrounding said blind bore and sized and shaped so as to support said top section of said cap member when said stem of said cap member is received within said blind bore of said base member, and at least one lateral bore intennediate said annular surface and said bottom surface of said blind bore, said at least one lateral bore extending generally transversely from an exterior wall of said base member to said blind bore and being alignable with said radial bore of said stem of said cap member when said stem is received in said blind bore of said base member; and fastening means for fastening said cap member to said base member when said stem is received within said blind bore of said base member and when said radial bore and said at least one lateral bore are aligned.
In another aspect, there is provided In a multi-component construct for cartilage and bone repair, said construct including a cap member shaped to form a stem having a longitudinal axis, which defines an axial direction, and a top section attached to one end of said stem and extending radially outward therefrom, said top section having first and second opposed surfaces, said first surface being sized and shaped so as to be adjacent an original cartilage layer at the defect site when said construct is positioned therein, and a base member sized and shaped so as to be adjacent a subchondral bone layer at the defect site when said construct is positioned therein, said base member including d proximal end proximate said second surface of said top section when said multi-component construct is assembled, a distal end remote from said cap member when said multi-component construct is assembled, and a blind bore extending in said axial direction from said proximal end toward said distal end, said blind bore being sized and shaped so as to receive said stem of said cap member, the improvement wherein: said cap member is formed from a first piece of cancellous bone which is demineralized to thereby provide said top section and said stem of said cap member with an elastic quality; said base member is formed from a second, separate piece of cancellous bone that is mineralized, whereby said base member does not have an elastic quality; and said second surface of said top section of said cap member is in direct contact with said proximal end of said base member upon assembly of said multi-component construct, whereby said base member supports said top section such that said first surface of said top section is substantially flush with an outer surface of the original cartilage layer at the defect site.
It is an object of the invention to provide an allograft implant for joints which provides pain relief, restores normal function and will postpone or alleviate the need for prosthetic replacement.
It is also an object of the invention to provide a cartilage repair implant which is easily placed in a defect area by the surgeon using an arthroscopic, minimally invasive technique.
It is still another object of the invention to provide an allograft implant which has load bearing capabilities.
It is further an object of the invention to provide an allograft implant procedure which is applicable for both partial and full thickness lesions.
7a It is yet another object of the invention to provide an allograft implant which facilitates growth of hyaline cartilage.
It is an additional object of the invention to provide a cancellous construct which is treated with chondrogenic stimulating factors.
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 7b accompanying drawings.
DRIEF .DESCRI.PTION OF THE DRAWINGS
Figure I shoves the anatotty of a knee joint.
-Figure 2 shows a schematic mosaieplasty as known in the prior art;
Figure 3 Stiows explod.ed perspectiveview of the inventive UV piece tantelionS construct;
figw:e 4 shows a top plan view of the. two piece allogmft cancellous eonstruct assembly showing the blind bore and plurality of through oing. bores in phantom;
Figure.5 snows a side elevation view of the two piecc. construct shownin Figum 4;
Fig= 6 is Side tth,,vation view.of the two pitve cotistruct ofure 4 turned9 with the blind and parallel' bores shownin phantom;
Figure 7 Shows aperSpective view of the basemember of the cancellous construct with the-e.* member removed;
Figure .ltow.s a perstIective view of the rap member of the cancellous construct;
Figure 9 is aside elevation view of the cap member shown in Figure 8; and Figure 10 is a Side elevation. vie.w of the to member-of tceoristruct of Figure 9- turned DESCAIMON CW TIN INVENTK)N
The term -"tissue" -is used in the general sense herein to meat/ any. asp ac or implantable 'tissue, the survivability of Which is impro'ved by the nietho.ds described herein upon -implantation, lit particular, the overall durability and lOngevity...of theimplant are improved, and host-immune system mediated respormes, are substantially eliminated.
The terms "transplant" and. "implanr are used interchang.eably to -refer to tissue,. material- or cells .(xenogerieie or alloseriele) which Tilay be introduced. into the body 4-)f a patient.
The terms "atitologous" and "tratogralr refer to tissue or cells which originate with or are derived from the recipient, whereas the terms "allogeneic" and "a raft" refer to cells and tissue which originate with OT are derived from 4 donor of the Same SpeCieS as the Tee:Ole/It The terms "xenoseneie" and ÷xenograft." refer to cells or tissue which originates with or are derived from a species other than that of tbe recipients 'The present invention is directml towards. a r.t.rtilage repair vmstruct construckxi of two setutrate o.f. allograft cancellous bone.
I3oth pieces oldie two-pkve allograft construct are to be derived front dense caneellous bone that may o.riginate from proximal or distal femur.: p.roximal or. diStal tibiaõ proximal luanerus, talus, calceneus, patella., or awn. Caneelious tissue isfirstprocessedinto blocks and then milled into the desired shapes. The top piece .or cap member is substardially dernineraliz.ed in dilute acid until thc tgme contains tem than- 0.2% AVM- residual. caleitun. -Subsequently, the :resultant tissue finm is .predorninantly Type collagen, whieli is sponge-like. in nature with.an elastic otaality. Follomrin decalcification, the tissue is further.elearie.d and: mayalso:be treated.ao that& cancellous tissue is non-o.steoinductive. = This- inactivation of inherent osteoinductivity may be.
accomplished via chemical or thermal treatment or -by high -energy inadiatiort. fri a prefertwi erilboditrient, the caneellouS cap member is -treated with an oxidizing agent. such as hydrogem .peroxikie hi order t.o aehieve .11.011-.0Steand active :material. The- bottom. piece be .fonned from mineralized cancellous bone or partially demineralized-cancellous bone.
The :two piece alloarafi cancellous construct 20 ha S a base Member 22- with a caprnerritier 30 Which is held fixed in place in .the base .m.ember by a pin 40. The 13aSe member 22 is preferably constructed oferalized cancellous bone and is shaped irithefOrm -o.fa.cylinderfur easy insertion into bores-cut into .the patient to cut away cartilage ciefect areas. However, the base member 22 iturõv be . face -or partially deinineralized Or mita:La a regiOn of cortical. bone So that it is corticalicancelloas. The body of the basenterriber 22 defines a blind 'bore 23 which holds the stein 3. of.the capinember 30. The bottom surface- 24. of the .blind bore -as seen in Figures 5-7 has a plurality &longitudinal through going bores 25 extending through. the basemember 22 and ending on the distal end surface 26 of the bast member which is preferably.planat.
The trip surface 27 of the base Member 22. is also prefentbly planar fox/nit* a. seat :fir the cap mem.ber 30. A transverse bore extead.s through the .diameter ofthet ylind.rical base above, the bottom surface 24 A-kfthe blind. bore 23 and intersects the blind bore 23. A. seermi plurality of through going bores 29 are.
eircurrife.rentiay pfAtioried around the Mind. bore. 23 parallel:to:the central axis Of the-base:Member 22 and extend from-the-top surfacv 27to the ht-tant surfiice26. The thrOugh going bores 25 and 29 haVe -a smaller diameter than-the blind 'bore 2 ít a diameter ranging-from -0.5 to .2.0 mm The cap -member 30 has a cylindrical tt., section 32 which has a thickness Of about 3 M11 With a top planar gorilla! 33,, an Outer ctirved wail 34 and-a -bottom Planar surface 35 which is seated adjacent the top surface 27 of the base member 22 when the components are mourned 14-)gether. The top surfate 33 while preferably planar may berailled to a degree of..curvatts.c that mak.es theiniplarn construct match the physiological. curvature in the knee. Larger constrects rnay.have a cap member that has multiple stem SectiOnsarid a base with an inverse "female' pattern which teceives the. stem sections. .An irai cylindrical stern 3fi extends away fro ebottoin planar surface 35 a length which is. not longer than the depth of the blind. bore 23:and bas a diameter equal to or less than -the-diameter a tb.0 blind tvr.e. 23. lbe stem. 36 defines a transverse t4r0u0 ping bore 37- which is:
aligned -With tntusverSe bore 28 Ofthe base member to receive a esVlindrical pin 40 which is :inserted radially through the construct to bold the cap mernbex 30 in place within the base member 22. The cap .member 30 is preferably formed -of dem ineralized canoellous allogatt boile with. a. calcium content less that/. of 0.2 `K, calcium or has a substantially demineralized region. Skteb. as the entire top .section, with a calcium content less than 02% calcium.. The :cylindrical pin 40 is preferably constnicted ofoortical bone arid has a length equal to or less than the diameter of-the base member 22-, Ihe ìncam:also be constructed of a- gritheticmaterialõ
The cap -member 30 can 'be. sectu0 to thy.! base member 22 by a staple, sutureõ, pressfit or an .adhesive court)ound such .aslibrin based glue.
'The construct 20 is placed in a detct area bore which has hccn cut in the lesion area of the -ilone of a -patient with the upper surface 26 of the cap metribe.r 30 beine -slightly proud, slightly:
below, or substantially flush with the surface of the original eartila.ge remaining at thearea being treated. The construct 20 has a: length which can be the same-asthe.depth of the defect -or more or leas than the depth of the 'bore If the construct 20 is die same as the depth of the bore 60, the base of the implant is supported by the 'bottom surthal.. of the bore and the top surilicz 33 of cap 3Q is:
substantially level with the articular cartilage. If the construet.20 is of a lesser length, the base ofthe constructisnot supported butsupportisprovided hy the And:la-the defect area bo.re. or .rt.õ-spective eut out area as the plug is interference fit within the bore or cut out area with the cap being slightly proud., slightly below, or flash with thestmounding articulareartilage depending .0n. the surgthafs-preference. 'With such load bearing support the graft surface is ta.A.
dartiaged by weight or bearing loads which can catat micromotion interfering with the graft interface producing fibrous tissue.
interfaces and stibehondral eytts.
If desired; a plurality o.f through-going bores .25 and 29- irfthe constmet allow cì migration throughout the construct to jYrOrnote cartilage grow-t . in the cartilage area and bone growth in the adjacent bore .region.
In operation, the lesion or defect is removed. b cuttinv, -a bore -removing a lesion in the implant area. If desired,. the open cancellous structnre of the cap -member 30 may be,' loaded. with a cartilage paste or gel tis rioted below anti/or one or more additives munely recombinant or native growth factors- (FCIF-2,.FGF-5, K1F-1, Itif-13,11MP-2, BMP-4, BMP-7,PDGF, VEGP), allogenic or innologous chondrocytes,..hunum al logertic.celia, hurmar allogenie or autologoua hone marrow cells:, hunm allogenic orautolo.gous stem cella, &mineralized bone matrixõ insuhn.õ
insulin-like growth factrir.-1, interlettkin-t weeptor antagonist, hetvtocyte gtowth factor, platelet, deriv.ed. growth factor, Indian hedgeh.og parathyroid honnorterelated peptide,. viral vectors tsr growth factor or 1)NA delivem nanoparticles, or platelet-ridh plasma. The construct 2(1 is then..
placed in die= lxne, or cut away area in .an interface fit "vvith the surrounding walls, =
the construct is Moveable within the. bore.0 shit:able organic Otte material can be ttfit...ldto keep the implant fixed in- place in the -implant area. Suitable organic glue .m.aterial can be found conimercially, suCh tisfor example;..'FISSERP TISSLICOLA (fibrin.based adhesive; ImMuno AG, Austria), .Adhesive Protein ( Sigma. Chemical, USA), i)ow Corning Medical Adhesive (Dow Corning, USA)õ fibrinogen throttibin, elastirt, collagen, csei.n. albumin, .k.eratin and the like..
The base oldie blind bore. 33 of the construet can alternatively be provided with- am.atrixof minced cartilage putty. or .gei coWlistipg -of inincod -orniIìe -allogrt.tft cartilage mthiCh has been.
lyophilized- so that -its water content ra.nges. from 0. I % tO 8.0% ranging from 25% to 50% by weight, mixed witho carrier of sodium hyaluroriate solution-(I1A) (tnoleetilar weight.ratigingfrom 7.0 s I 0' to 1..2 x 106) or any other bioabsorbable carrier such as hyalartmic acid and its =derivativesõ gìatn Collagen, .ebitosart, alginate, buil:red PBSõ Dextra.n, or polynters, the atrrier ranging .frorn ranging from 75% to .50% 'by. weight.. The cartilage is milled to a size ranging tm to I min.

In the .gel form, the minced cartilage has -been lyophilized so that its water content .rarAges from 0.1%, to. 8,0%, ranging from 15% to .10% by weight aild the miller ranges from 85% to. -101,'Zi bY
weight. The particle size of the etrtí. lage when. milled is less than or equal to 1 mm dry. The cartilage 'Ames cam be processed to varying, particle-sizes and the: ILA, or other carrier can have different viscosities depending. on the deshtd consistency of the putty or gel. This cartilage matrix.
can be deposited inn) the matrix of the &mineralized cap .member. The putty or gel enhances the.
tissue integration between the plug and host tissue.
It is also envisioned that dernineralizei bone matrbt andior grOWth radon stich -as (FGF-2, B1.1)-4, IVI. .PDCW, VEciFyor soluble :factors welt as insulin, intetlenkin-1 receptor antagonist, hepatocytegrowthiactOr, Indian -hedgehog and partultyroid hornione-mlatcd vt,.ctors .for erowth factor or DNA delivery,. nanopartieles may be adsorbed or combined %kith tfie.scaffold or the cartilage:fragments. In another em.bodimentõ platelet-rich plasma may be added. to .the .scaffold, isalso errvisioned-that cells vbitich have been grown outSide the patient Carl -kle inserted by syringe into the caneellous cap. matrix betbre, during or after deposit of the construct 2) into the defb..1 .area. Snell cells include allogenie orautolOgous, bone matrow cs.
stern -cells and eliondtocyte:cel.ls. The cellular density (lithe eons preferably ranges from 1.0 x to 5.0-x 10 or frOM about 100 minim to about 500 million cells per co ofpinty or gel.
rnixtum, This matrix can support the p:e..viously m.entioned Chondrogenie stimulating factors.
The principles, preferred. on bodiments and meties of openition of-the present inve,ntion have been.describralin the femgoing specification. However, the -invention Should not be consulted as limited to the partied& embodiments.Which have.beendeseribed above. Instead, tile einbOdiments described here should be regardei as illustrative rather than restrictive.
'Variations and changes may be made by otbets v4tithOut departing from the scope of the -present inverition as defined: by the f011owing

Claims

1. A construct for cartilage repair, comprising:
a cap member formed from bone, said cap member including a stem having a longitudinal axis, which defines an axial direction, and a radial bore extending generally transversely into said stem from an exterior surface thereof, and a top section attached to one end of said stem and extending radially outward therefrom, said top section being substantially demineralized, whereby said top section has an elastic quality;
a base member at least partially formed from mineralized bone, said base member including a blind bore extending in said axial direction from one end of said base member toward an opposite end thereof and sized and shaped so as to receive said stem of said cap member, said blind bore having a bottom surface intermediate said one end of said base member and said opposite end of said base member, said one end of said base member including an annular surface surrounding said blind bore and sized and shaped so as to support said top section of said cap member when said stem of said cap member is received within said blind bore of said base member, and at least one lateral bore intermediate said annular surface and said bottom surface of said blind bore, said at least one lateral bore extending generally transversely from an exterior wall of said base member to said blind bore and being alignable with said radial bore of said stem of said cap member when said stem is received in said blind bore of said base member; and fastening means for fastening said cap member to said base member when said stem is received within said blind bore of said base member and when said radial bore and said at least one lateral bore are aligned.

2. The construct of claim 1, wherein said stem includes a free end opposite said one end of said stem.

3. The construct of claim 2, wherein said radial bore of said stem is positioned intermediate said free end of said stem and said one end of said stem.

4. The construct of claim 1, wherein said at least one lateral bore includes a first lateral bore located on one side of said base member and a second lateral bore located on an opposite side of said base member in coaxial alignment with said first lateral bore, said radial bore of said stem being alignable with said first and second lateral bores of said base member when said stem is received in said blind bore of said base member.

5. The construct of claim 4, wherein said fastening means includes a pin sized and shaped so as to be insertable into said first and second lateral bores of said base member and said radial bore of said stem, when said stem is received in said blind bore of said base member such that said radial bore of said stem is in coaxial alignment with said first and second lateral bores of said base member.

6. The construct of claim 5, wherein said pin is formed from allograft bone.

7. In a multi-component construct for cartilage and bone repair, said construct including a cap member shaped to form a stem having a longitudinal axis, which defines an axial direction, and a top section attached to one end of said stem and extending radially outward therefrom, said top section having first and second opposed surfaces, said first surface being sized and shaped so as to be adjacent an original cartilage layer at the defect site when said construct is positioned therein, and a base member sized and shaped so as to be adjacent a subchondral bone layer at the defect site when said construct is positioned therein, said base member including a proximal end proximate said second surface of said top section when said multi-component construct is assembled, a distal end remote from said cap member when said multi-component construct is assembled, and a blind bore extending in said axial direction from said proximal end toward said distal end, said blind bore being sized and shaped so as to receive said stem of said cap member, the improvement wherein:
said cap member is formed from a first piece of cancellous bone which is demineralized to thereby provide said top section and said stem of said cap member with an elastic quality;
said base member is formed from a second, separate piece of cancellous bone that is mineralized, whereby said base member does not have an elastic quality; and said second surface of said top section of said cap member is in direct contact with said proximal end of said base member upon assembly of said multi-component construct, whereby said base member supports said top section such that said first surface of said top section is substantially flush with an outer surface of the original cartilage layer at the defect site.

8. The construct of claim 7, wherein said blind bore of said base member includes a bottom surface intermediate said proxima; end of said base member and said distal end of said base member.

9. The construct of claim 8, wherein an opposite end of said stem, remote from said top section of said cap member, is in direct contact with said bottom surface of said blind bore of said base member upon assembly of said multi-component construct.

10. The construct of claim 7, wherein said first surface of said top section is planar.

11. The construct of claim 7, wherein said first piece of cancellous bone has a calcium content of less than 0.2%.

12. The construct of claim 7, wherein said top section of said cap member has a first diameter and said base member has a second diameter that is substantially equal to said first diameter, whereby said proximal end of said base member is substantially coextensive with said top section of said cap member.