US20080167716A1 - Cartilage repair apparatus and method - Google Patents

Abstract

An orthopaedic device for repairing and regenerating cartilage includes a plug configured to be positioned in a hole formed in the cartilage and an anchor configured to support the plug. One or both of the plug and the anchor may be formed from naturally occurring extracellular matrix such as small intestine submucosa. A method for repairing and regenerating cartilage is also disclosed.

Description

• This application is a continuation of U.S. patent application Ser. No. 10/195,347, filed on Jul. 15, 2002, which claims priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 60/305,786, filed Jul. 16, 2001, and to U.S. Provisional Application No. 60/389,027, filed Jun. 14, 2002, the entirety of each of which is expressly incorporated by reference herein.
CROSS REFERENCE
• Cross reference is made to copending U.S. patent application Ser. No. 10/195,795 entitled “Meniscus Regeneration Device and Method” (Attorney Docket No. 265280-71141, DEP-745); Ser. No. 10/195,719 entitled “Devices from Naturally Occurring Biologically Derived Materials” (Attorney Docket No. 265280-71142, DEP-748); Ser. No. 10/195,344 entitled “Unitary Surgical Device and Method” (Attorney Docket No. DEP-750); Ser. No. 10/195,341 entitled “Hybrid Biologic/Synthetic Porous Extracellular Matrix Scaffolds” (Attorney Docket No. 265280-71144, DEP-751); Ser. No. 10/195,606 entitled “Cartilage Repair and Regeneration Device and Method” (Attorney Docket No. 265280-71145, DEP-752); Ser. No. 10/195,354 entitled “Porous Extracellular Matrix Scaffold and Method” (Attorney Docket No. 265280-71146, DEP-763); Ser. No. 10/195,334 entitled “Cartilage Repair and Regeneration Scaffolds and Method” (Attorney Docket No. 265280-71180, DEP-763); and Ser. No. 10/195,633 entitled “Porous Delivery Scaffold and Method” (Attorney Docket No. 265280-71207, DEP-762), each of which is assigned to the same assignee as the present application, each of which is filed concurrently herewith, and each of which is hereby incorporated by reference. Cross reference is also made to U.S. patent application Ser. No. 10/172,347 entitled “Hybrid Biologic-Synthetic Bioabsorbable Scaffolds” which was filed on Jun. 14, 2002, which is assigned to the same assignee as the present application, and which is hereby incorporated by reference.
FIELD OF THE DISCLOSURE
• The present disclosure relates generally to devices for attaching, repairing, or regenerating damaged or diseased cartilage.
BACKGROUND
• Articular cartilage is a type of hyaline cartilage that lines the surfaces of the opposing bones in a diarthrodial joint (e.g. knee, hip, shoulder, etc.). Articular cartilage provides a near-frictionless articulation between the bones, while also functioning to absorb and transmit the compressive and shear forces encountered in the joint. Further, since the tissue associated with articular cartilage is aneural, these load absorbing and transmitting functions occur in a painless fashion in a healthy joint.
• However, when articular cartilage tissue is no longer healthy it can cause debilitating pain in the joint. Cartilage health can be affected by disease, aging, or trauma, all of which primarily involve a breakdown of the matrix consisting of a dense network of proteoglycan aggregates, collagen type II fibers, and other smaller matrix proteins. Cartilage cells, called chondrocytes, are unable to induce an adequate healing response because they are unable to migrate, being enclosed in lacunae surrounded by a dense matrix. Further, since the tissue is avascular, initiation of healing by circulating cells is not possible.
• Several cartilage repair strategies have been attempted in the past. These include surgical techniques such as microfracturing or performing an abrasion arthroplasty on the bone bed to gain vascular access, and hence, stimulate extrinsic repair in the defective region.
• Another surgical technique is mosaicplasty or osteochondral autograft transfer system (OATS). In this case, cylindrical plugs of healthy cartilage from a low-load bearing region of the knee are taken and transplanted into the defective region.
• The only FDA-approved cartilage treatment in the market involves autologous chondrocyte implantation (CartiCel™). Autologous chondrocyte implantation involves performing an initial biopsy of healthy cartilage from the patient, isolating the cells from the tissue, expanding the cells in vitro by passaging them in culture, and then reintroducing them into the defective area. The cells are retained within the defect by applying a periosteal tissue patch over the defect, suturing the edges of the patch to the host tissue, and then sealing with fibrin glue. The healing observed is similar to that observed with microfracture or abrasion of the bone bed, indicating that it is the preparation of the bone bed and not the introduction of the cells that facilitates the healing process.
• Tissue engineering strategies for healing cartilage are being investigated by several academic and commercial teams and show some promise. The approach primarily involves using a carrier or a scaffold to deliver cells or stimulants to the defect site. The scaffold material can be a purified biologic polymer in the form of a porous scaffold or a gel (purified collagens, glycoproteins, proteoglycans, polysaccharides, or the like in various combinations) or porous scaffolds of synthetic biodegradable polymers (PLA, PGA, PDS, PCL, or the like in various combinations). Several challenges remain with this approach, however. Some of these challenges include retention of the active stimulant at the defect site, inability to control the rate of release of the stimulant (resulting in tissue necrosis due to overdose), cytotoxicity of the cells due to the degradation by-products of the synthetic polymers.
• As alluded to above, it is known to use various collagen scaffolds to provide a scaffold for repair and regeneration of damaged tissue. U.S. Pat. No. 6,042,610 to ReGen Biologics, hereby incorporated by reference, discloses the use of a device comprising a bioabsorbable material made at least in part from purified natural fibers. The purified natural fibers are crosslinked to form the device. The device can be used to provide augmentation for a damaged meniscus. Related U.S. Pat. Nos. 5,735,903, 5,479,033, 5,306,311, 5,007,934, and 4,880,429 also disclose a meniscal augmentation device for establishing a scaffold adapted for ingrowth of meniscal fibrochondrocyts.
• It is also known to seed collagenous scaffolds with cells. See, e.g., U.S. Pat. Nos. 6,379,367 and 6,283,980, the disclosure of each of which is hereby incorporated by reference.
• It is also known to use naturally occurring extracelluar matrices (ECMs) to provide a scaffold for tissue repair and regeneration. One such ECM is small intestine submucosa (SIS). SIS has been used to repair, support, and stabilize a wide variety of anatomical defects and traumatic injuries. Commercially available SIS material is derived from porcine small intestinal submucosa that remodels to the qualities of its host when implanted in human soft tissues. Further, it is taught that the SIS material provides a natural scaffold-like matrix with a three-dimensional microstructure and biochemical composition that facilitates host cell proliferation and supports tissue remodeling. Indeed, SIS has been shown to contain biological molecules, such as growth factors and glycosaminoglycans, that aid in the repair of soft tissue in the human body. SIS products, such as OASIS and SURGISIS, are commercially available from Cook Biotech Inc., Bloomington, IN.
• Another SIS product, RESTORE® Orthobiologic Implant, is available from DePuy Orthopaedics, Inc. in Warsaw, Indiana. The DePuy product is described for use during rotator cuff surgery, and is provided as a resorbable framework that allows the rotator cuff tendon to regenerate. The RESTORE Implant is derived from porcine small intestine submucosa, a naturally occurring ECM (composed of mostly collagen type I (about 90% of dry weight), glycosaminoglycans and other biological molecues) that has been cleaned, disinfected, and sterilized. During seven years of preclinical testing in animals, there were no incidences of infection transmission from the implant to the host, and the SIS material has not adversely affected the systemic activity of the immune system.
• While small intestine submucosa is available, other sources of ECM are known to be effective for tissue remodeling. These sources include, but are not limited to, stomach, bladder, alimentary, respiratory, and genital submucosa, and liver basement membrane. See, e.g., U.S. Pat. Nos. 6,379,710, 6,171,344, 6,099,567, and 5,554,389, hereby incorporated by reference. Further, while SIS is most often porcine derived, it is known that these various submucosa materials may be derived from non-porcine sources, including bovine and ovine sources. Additionally, the ECM material may also include partial layers of laminar muscularis mucosa, muscularis mucosa, lamina propria, stratum compactum layer and/or other such tissue materials depending upon other factors such as the source from which the ECM material was derived and the delamination procedure.
• For the purposes of this disclosure, it is within the definition of a naturally occurring ECM to clean and/or comminute the ECM, or to cross-link the collagen within the ECM. However, it is not within the definition of a naturally occurring ECM to separate and purify the natural fibers and reform a matrix material from purified natural fibers. Also, while reference is made to SIS, it is understood that other naturally occurring ECMs, such as stomach, bladder, alimentary, respiratory, or genital submucosa, or liver basement membrane, for example, whatever the source (e.g. bovine, porcine, ovine, etc.) are within the scope of this disclosure. Thus, as used herein, the terms “naturally occurring extracellular matrix” or “naturally occurring ECM” are intended to refer to extracellular matrix material that has been cleaned, disinfected, sterilized, and optionally cross-linked. The terms “naturally occurring extracellular matrix” and “naturally occurring ECM” are also intended to include ECM foam material prepared as described in copending U.S. patent application Ser. No. 10/195,354 entitled “Porous Extracellular Matrix Scaffold and Method” (Attorney Docket No. 265280-71146, DEP-747), filed concurrently herewith.
• The following patents, hereby incorporated by reference, disclose the use of ECMs for the regeneration and repair of various tissues: 6,379,710; 6,187,039; 6,176,880; 6,126,686; 6,099,567; 6,096,347; 5,997,575; 5,993,844; 5,968,096; 5,955,110; 5,922,028; 5,885,619; 5,788,625; 5,733,337; 5,762,966; 5,755,791; 5,753,267; 5,711,969; 5,645,860; 5,641,518; 5,554,389; 5,516,533; 5,460,962; 5,445,833; 5,372,821; 5,352,463; 5,281,422; and 5,275,826.
• It is known to use such materials as catgut and SIS to make appliances. See the Bolesky published application WO 95/06439. The Bolesky application discloses devices that are semi-rigid and are formed into desired shapes, but Bolesky does not disclose a process for fabricating naturally occurring extracellular matrix parts so that they are rigid and hardened.
SUMMARY
• The concepts of the present disclosure provide for an implantable, biodegradable cartilage repair device. In an illustrative embodiment, there is provided an implantable cartilage repair device which includes a plug formed of a naturally occurring extracellular matrix. The density and porosity of the extracellular matrix material can be controlled with compression drying, including air drying, air drying with heat, vacuum drying, vacuum drying with heat, and freeze drying. Thus, the ECM material can be dried to have a hardness sufficient to machine the device, without the need to form the device into the general shape by molding. By managing density and porosity of the ECM various matrices and fixation devices may be fabricated having superior material properties which allow the device to promote healing while remaining biodegradable.
• In a more specific illustrative embodiment, there is provided an orthopaedic device for repairing and regenerating cartilage. The device includes a plug configured to be positioned in a hole formed in the cartilage and an anchor configured to support the plug and engage the subchondral bone. One or both of the plug and the anchor may be formed from naturally occurring extracellular matrix.
• For example, a mass of naturally occurring ECM may be cured to be very rigid and hardened so that it can be machined using conventional cutting tools and/or laser machining. As such, the anchor and/or the plug may be formed by machining a mass of cured matrix to define the structural features thereof. The mass may be formed by compressing the ECM into a solid mass. For example, the ECM may be comminuted and formed into a solid mass with interlocking strands of ECM.
• For example, a tightly balled up or compacted mass of pieces of SIS or even comminuted SIS may be hardened by air drying or by hot air drying to become extremely hard. Unexpectedly, this hardened SIS may be machined or formed to have very sharp pointed ends, sharp barbs, etc. With this process, anchors, tacks, barbed tacks, and staples may be machined from such cured mass of SIS.
• In one embodiment, there is provided a device for repairing a diseased or damaged portion of articular cartilage on a bone of a joint. The cartilage is prepared by forming an opening therein to remove the diseased or damaged portion. The device includes a plug configured to be positioned in the cartilage opening. The plug has generally the shape of the opening. The device also includes an anchor configured to position and hold the plug in the opening. The plug is formed of naturally occurring extracellular matrix shaped and dried to have a structural strength sufficient to withstand the compression and shear stresses involved in the joint. The plug is secured to the anchor so as to be in contact with the bone.
• In regard to another embodiment, there is provided a method for repairing a diseased or damaged portion of articular cartilage on a bone. The method includes the step of forming an opening in the articular cartilage so as to remove the diseased or damaged portion thereof. The method also includes the step of positioning a plug in the opening so as to be adjacent healthy articular cartilage. The plug is formed of a naturally occurring extracellular matrix cured to have a structural rigidity to withstand the compression and shear stress placed on the articular cartilage.
BRIEF DESCRIPTION OF THE DRAWINGS
• FIG. 1 is a cross sectional view of a cartilage repair device implanted in subchondral bone, note that the anchor is shown in elevation rather than cross section for clarity of description;
• FIGS. 2-4 are views similar toFIG. 1, but showing additional embodiments of a cartilage repair device;
• FIG. 5 is a cross sectional view of a cartilage repair device which utilizes an alternative embodiment of an anchor;
• FIG. 6 is a cross sectional view of a cartilage repair device which utilizes an anchor in the form of a staple to secure the assembly to the subchondral bone, note thatFIG. 6 includes an encircled portion showing a perspective view of the staple and plug;
• FIG. 7 is a cross sectional view of a cartilage repair device which utilizes an anchor in the form of a ring to secure the assembly to the subchondral bone;
• FIGS. 8-10 are perspective views of a number of embodiments of the rings ofFIG. 7;
• FIG. 11 is an enlarged perspective view of a cartilage repair device which utilizes an alternative embodiment of an anchor, note that a portion of one of the tubes has been cut away for clarity of description to expose the barb positioned therein;
• FIG. 12 is a cross sectional view showing the cartilage repair device ofFIG. 11 secured to the native cartilage, note that the anchor is shown in elevation rather than cross section for clarity of description; and
• FIG. 13 is a cross sectional view showing the cartilage repair device ofFIG. 11 secured to the subchondral bone, note that the anchor is shown in elevation rather than cross section for clarity of description.
DETAILED DESCRIPTION OF THE DRAWINGS
• While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that there is no intent to limit the disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the disclosure as defined by the appended claims.
• Referring now toFIG. 1, there is shown acartilage repair device10 for repairing damaged or diseased cartilage. Thedevice10 includes ananchor12 which is anchored or otherwise positioned in an opening formed in both a section ofnative cartilage16 and the underlyingsubchondral bone18. Theanchor12 is configured to be secured in an area from which damaged, diseased, or destroyed native cartilage and possibly bone have been removed. Theanchor12 includes an elongatedcentral body portion20 and ahead portion22. Thebody portion20 extends downwardly from a lower surface of thehead portion22. As shown inFIG. 1, thebody portion20 may have a number ofbarbs24 extending therefrom for engaging the sidewalls of the opening formed in thebone18. In the illustrative embodiment described herein, thebarbs24 extend radially outwardly and are inclined slightly toward thehead portion22 of theanchor12.
• Thecartilage repair device10 also includes a scaffold or plug26. Theplug26 is secured to theanchor12. Specifically, theplug26 is secured to the upper surface of thehead portion22 of theanchor12. Theplug26 allows for communication across the removed portion (i.e., the portion of thenative cartilage16 from which the damaged or diseased cartilage has been removed) and the adjacent healthy cartilage. As such, theplug26 functions as a chondrogenic growth-supporting matrix for promoting a positive cellular response in an effort to achieve articular cartilage regeneration.
• Theanchor12 of thecartilage repair device10 may be constructed of numerous types of synthetic or naturally occurring materials. For example, theanchor12 may be constructed with a bioabsorbable polymer. Examples of such polymers include: polyesters of [alpha]-hydroxycarboxylic acids, such as poly(L-lactide) (PLLA), polyglycolide (PGA); poly-p-dioxanone (PDO); polycaprolactone (PCL); and any other bioresorbable and biocompatible polymer, co-polymer or mixture of polymers or co-polymers that are commonly utilized in the construction of prosthetic implants. Moreover, theanchor12 may be constructed with a naturally occurring material such as a naturally occurring ECM (e.g., SIS). In such a case, thehead portion22 andbody portion20 of theanchor12 may be configured as monolithic structures formed from naturally occurring ECM which is cured to be rigid and hardened to facilitate attachment to thebone18. As such, it should be appreciated that the ECM material from which theanchor12 is fabricated is cured to produce a structure which possesses the necessary hardness and toughness to allow theanchor12 to be driven into bone tissue (i.e., the subchondral bone18).
• It should be understood that the material selected for theanchor12 may also comprise mixtures or composites of materials. For example, theanchor12 could comprise both a polymer and ECM material.
• ECM material with the necessary hardness and toughness for use as theanchor12, along with other devices constructed from ECM disclosed herein, may be fabricated by compacting comminuted or shredded naturally occurring ECM material into bar or rod stock by compressing the material together and then curing the material such that it is very rigid and hardened. The curing may be accomplished by simple air drying or by heated air drying of the formed stock. Moreover, the entire structure may be cross-linked.
• In a specific exemplary embodiment, theanchor12 may be constructed with a cured and hardened SIS. In this case, comminuted SIS material is placed in a container and allowed to air dry for a predetermined period of time (e.g., as long as several days) at room temperature. Over such a time, water evaporates from the SIS material thereby shrinking the material. The shrunk material is very tough and hard and, as a result, may be machined as described herein.
• It should be appreciated that other process parameters may be established to facilitate the curing process. For example, a curing profile utilizing predetermined amounts of heat and/or pressure may be designed to facilitate the curing of the naturally occurring ECM material (e.g., SIS).
• Once the ECM material (e.g., SIS) is cured to a desired hardness and toughness, it may be machined with conventional machining equipment to desired shapes. For example, theanchor12 may be turned on a lathe or similar equipment to produce the desired configuration of thehead portion22 and the body portion20 (including, for example, the barbs24). However, based on the specific design of theanchor12, it should be appreciated that certain features of the anchor12 (e.g., the barbs24) may be separately or additionally machined to produce a desired shape or geometry. For example, various barb configurations may be formed on thebody portion20 of theanchor12 by, for example, use of a cutting machine.
• In addition to conventional machining techniques (e.g., lathing and cutting), contemporary techniques may also be utilized to form the cured naturally occurring ECM into the desired configuration of theanchor12. For example, a programmable laser cutting machine may be utilized to cut the raw stock of cured ECM. Specifically, the laser cutting machine may be programmed to cut the raw stock in a pattern which produces a desired configuration of theanchor12. In addition to providing for cutting with precision tolerances, laser cutting also provides other benefits. For example, such laser cutting of the ECM products, for example, barbs having cut edges which are sealed and fused together to enhance the attachment capability of the barbs. In addition, naturally occurring ECM can be molded and cured into the desired shapes.
• As alluded to above, theplug26 functions as a chondrogenic growth-supporting matrix for promoting vascular invasion and cellular proliferation in an effort to achieve articular cartilage regeneration. Acentral body30 of theplug26 is configured as a porous structure constructed from a naturally occurring ECM material such as SIS. As such, when anchored to a defective area of cartilage, cells can migrate into and proliferate within theplug26, biodegrade theplug26 while, at the same time, synthesize new and healthy tissue to heal the defective area. Theplug26 may be made out of comminuted and/or lyophilized naturally occurring ECM (e.g. SIS) with the desired porosity and material density. Specifically, the material density and/or porosity of theplug26 may be varied to control cell migration and proliferation. The cells can migrate from adjacent tissue or from synovial fluid.
• Theplug26 may additionally be chemically crosslinked with, for example, aldehydes, carbodiimides, enzymes, or the like. Theplug26 may also be physically crosslinked. Physical crosslinking may be accomplished by freeze-drying or fusing by physical means (e.g., thermal crosslinking by the application of heat, radiation crosslinking by the application of ultraviolet or gamma irradiation, or dehydrothermal crosslinking by the application of a combination of heat and drying).
• Theplug26 may also include bioactive agents, biologically derived substances (e.g. stimulants), cells, biologically compatible inorganic materials and/or biocompatible polymers.
• “Bioactive agents” include one or more of the following: chemotactic agents; therapeutic agents (e.g. antibiotics, steroidal and non-steroidal analgesics and anti-inflammatories, anti-rejection agents such as immunosuppressants and anti-cancer drugs); various proteins (e.g. short chain peptides, bone morphogenic proteins, glycoprotein and lipoprotein); cell attachment mediators; biologically active ligands; integrin binding sequence; ligands; various growth and/or differentiation agents (e.g. epidermal growth factor, IGF-I, IGF-II, TGF-β I-III, growth and differentiation factors, vascular endothelial growth factors, fibroblast growth factors, platelet derived growth factors, insulin derived growth factor and transforming growth factors, parathyroid hormone, parathyroid hormone related peptide, bFGF; TGF_βsuperfamily factors; BMP-2; BMP-4; BMP-6; BMP-12; sonic hedgehog; GDF5; GDF6; GDF8; PDGF); small molecules that affect the upregulation of specific growth factors; tenascin-C; hyaluronic acid; chondroitin sulfate; fibronectin; decorin; thromboelastin; thrombin-derived peptides; heparin-binding domains; heparin; heparan sulfate; DNA fragments and DNA plasmids. If other such substances have therapeutic value in the orthopaedic field, it is anticipated that at least some of these substances will have use in concepts of the present disclosure, and such substances should be included in the meaning of “bioactive agent” and “bioactive agents” unless expressly limited otherwise.
• “Biologically derived agents” include one or more of the following: bone (autograft, allograft, and xenograft) and derivates of bone; cartilage (autograft, allograft and xenograft), including, for example, meniscal tissue, and derivatives; ligament (autograft, allograft and xenograft) and derivatives; derivatives of intestinal tissue (autograft, allograft and xenograft), including for example submucosa; derivatives of stomach tissue (autograft, allograft and xenograft), including for example submucosa; derivatives of bladder tissue (autograft, allograft and xenograft), including for example submucosa; derivatives of alimentary tissue (autograft, allograft and xenograft), including for example submucosa; derivatives of respiratory tissue (autograft, allograft and xenograft), including for example submucosa; derivatives of genital tissue (autograft, allograft and xenograft), including for example submucosa; derivatives of liver tissue (autograft, allograft and xenograft), including for example liver basement membrane; derivatives of skin tissue; platelet rich plasma (PRP), platelet poor plasma, bone marrow aspirate, demineralized bone matrix, insulin derived growth factor, whole blood, fibrin and blood clot. Purified ECM and other collagen sources are also intended to be included within “biologically derived agents.” If other such substances have therapeutic value in the orthopaedic field, it is anticipated that at least some of these substances will have use in the concepts of the present disclosure, and such substances should be included in the meaning of “biologically-derived agent” and “biologically-derived agents” unless expressly limited otherwise.
• “Biologically derived agents” also include bioremodelable collageneous tissue matrices. The expressions “bioremodelable collagenous tissue matrix” and “naturally occurring bioremodelable collageneous tissue matrix” include matrices derived from native tissue selected from the group consisting of skin, artery, vein, pericardium, heart valve, dura mater, ligament, bone, cartilage, bladder, liver, stomach, fascia and intestine, tendon, whatever the source. Although “naturally occurring bioremodelable collageneous tissue matrix” is intended to refer to matrix material that has been cleaned, processed, sterilized, and optionally crosslinked, it is not within the definition of a naturally occurring bioremodelable collageneous tissue matrix to purify the natural fibers and reform a matrix material from purified natural fibers. The term “bioremodelable collageneous tissue matrices” includes “extracellular matrices” within its definition.
• “Cells” include one or more of the following: chondrocytes; fibrochondrocytes; osteocytes; osteoblasts; osteoclasts; synoviocytes; bone marrow cells; mesenchymal cells; stromal cells; stem cells; embryonic stem cells; precursor cells derived from adipose tissue; peripheral blood progenitor cells; stem cells isolated from adult tissue; genetically transformed cells; a combination of chondrocytes and other cells; a combination of osteocytes and other cells; a combination of synoviocytes and other cells; a combination of bone marrow cells and other cells; a combination of mesenchymal cells and other cells; a combination of stromal cells and other cells; a combination of stem cells and other cells; a combination of embryonic stem cells and other cells; a combination of precursor cells isolated from adult tissue and other cells; a combination of peripheral blood progenitor cells and other cells; a combination of stem cells isolated from adult tissue and other cells; and a combination of genetically transformed cells and other cells. If other cells are found to have therapeutic value in the orthopaedic field, it is anticipated that at least some of these cells will have use in the concepts of the present disclosure, and such cells should be included within the meaning of “cell” and “cells” unless expressly limited otherwise.
• “Biological lubricants” include: hyaluronic acid and its salts, such as sodium hyaluronate; glycosaminoglycans such as dermatan sulfate, heparan sulfate, chondroiton sulfate and keratan sulfate; synovial fluid and components of synovial fluid, including as mucinous glycoproteins (e.g. lubricin), vitronectin, tribonectins, articular cartilage superficial zone proteins, surface-active phospholipids, lubricating glycoproteins I, II; and rooster comb hyaluronate. “Biological lubricant” is also intended to include commercial products such as ARTHREASE ™ high molecular weight sodium hyaluronate, available in Europe from DePuy International, Ltd. of Leeds, England, and manufactured by Bio-Technology General (Israel) Ltd., of Rehovot, Israel; SYNVISC® Hylan G-F 20, manufactured by Biomatrix, Inc., of Ridgefield, N. J. and distributed by Wyeth-Ayerst Pharmaceuticals of Philadelphia, Pa.; HYLAGAN® sodium hyaluronate, available from Sanofi-Synthelabo, Inc., of New York, N.Y., manufactured by FIDIA S.p.A., of Padua, Italy; and HEALON® sodium hyaluronate, available from Pharmacia Corporation of Peapack, New Jersey in concentrations of 1%, 1.4% and 2.3% (for opthalmologic uses). If other such substances have therapeutic value in the orthopaedic field, it is anticipated that at least some of these substances will have use in the concepts of the present disclosure, and such substances should be included in the meaning of “biological lubricant” and “biological lubricants” unless expressly limited otherwise.
• “Biocompatible polymers” is intended to include both synthetic polymers and biopolymers (e.g. collagen). Examples of biocompatible polymers include: polyesters of [alpha]-hydroxycarboxylic acids, such as poly(L-lactide) (PLLA) and polyglycolide (PGA); poly-p-dioxanone (PDO); polycaprolactone (PCL); polyvinyl alchohol (PVA); polyethylene oxide (PEO); polymers disclosed in U.S. Pat. Nos. 6,333,029 and 6,355,699; and any other bioresorbable and biocompatible polymer, co-polymer or mixture of polymers or co-polymers that are utilized in the construction of prosthetic implants. In addition, as new biocompatible, bioresorbable materials are developed, it is expected that at least some of them will be useful materials from which orthopaedic devices may be made. It should be understood that the above materials are identified by way of example only, and the present invention is not limited to any particular material unless expressly called for in the claims.
• “Biocompatible inorganic materials” include materials such as hydroxyapatite, all calcium phosphates, alpha-tricalcium phosphate, beta-tricalcium phosphate, calcium carbonate, barium carbonate, calcium sulfate, barium sulfate, polymorphs of calcium phosphate, ceramic particles, and combinations of such materials. If other such substances have therapeutic value in the orthopaedic field, it is anticipated that at least some of these substances will have use in the concepts of the present disclosure, and such substances should be included in the meaning of “biocompatible inorganic material” and “biocompatible inorganic materials” unless expressly limited otherwise.
• It is expected that various combinations of bioactive agents, biologically derived agents, cells, biological lubricants, biocompatible inorganic materials, biocompatible polymers can be used with the devices of the present disclosure.
• Illustratively, in one example of embodiments that are to be seeded with living cells such as chondrocytes, a sterilized implant may be subsequently seeded with living cells and packaged in an appropriate medium for the cell type used. For example, a cell culture medium comprising Dulbecco's Modified Eagles Medium (DMEM) can be used with standard additives such as non-essential aminoacids, glucose, ascorbic acid, sodium pyrovate, fungicides, antibiotics, etc., in concentrations deemed appropriate for cell type, shipping conditions, etc.
• It should be understood that the material selected for theplug26 may also comprise mixtures or composites of materials. For example, theplug26 could comprise both a polymer and ECM material.
• The ECM from which theplug26 is constructed may be confirmed to have a structural rigidity sufficient to withstand the compression and shear stress to which thecartilage16 is subjected. Specifically, theplug26 in the illustrated embodiments has an outer surface which defines an articular surface on which the cartilage from the other bone of the joint bears. As such, the ECM from which theplug26 is constructed to have the structural rigidity necessary to bear the forces associated with the other bone.
• One particularly useful material for fabricating theplug26 is a porous scaffold or “foam” composed of naturally occurring ECM. For example, theplug26 may be constructed from a porous SIS foam. In such a manner, both the material density and the pore size of thefoam plug26 may be varied to fit the needs of a given plug design. Such foams may be fabricated by lyophilizing (i.e., freeze-drying) comminuted ECM (i.e., SIS) suspended in water. The material density and pore size of the resultant foam may be varied by controlling, amongst other things, the rate of freezing of the comminuted SIS suspension and/or the amount of water or moisture content in the comminuted SIS at the on-set of the freezing process.
• The following is a specific example of a process for fabricating an exemplary SIS foam. The first step in developing a foam with a desired pore size and density is the procurement of comminuted SIS. To do so, scissor-cut SIS runners (˜6″ long) are positioned in a 1700 series Comitrol™ machine which is commercially available from Urschel Laboratories of Valpraiso, Indiana. The SIS material is processed and thereafter collected in a receptacle at the output of the machine. The material is then processed through the machine a second time under similar conditions. The resultant material is a “slurry” of SIS material (thin, long SIS fibers ˜200 microns thick×1-5 mm long) suspended substantially uniformly in water.
• Thereafter, the comminuted SIS suspension is dried. To do so, a lyophilization process (freeze drying) is used. In particular, the SIS suspension is frozen at a controlled temperature drop rate to control the size of the formed ice crystals. Without allowing the material to thaw, the process of lyopihlization sublimes ice crystals directly to vapor under vacuum and low temperatures. This leaves voids in the spaces previously occupied by ice crystals. One exemplary machine for performing such is a freeze drying process is a Virtis Genesis™ Series lyophilizer which is commercially available from SP Industries, Inc. of Gardiner, N.Y.
• The process parameters of the lyophilization process may be varied to produce foams of varying pore sizes and material densities. For example, to produce foams having a relatively large pore size and a relatively low material density, the comminuted SIS suspension may be frozen at a slow, controlled rate (e.g., −1° C./min or less) to a temperature of about −20° C. prior to lyophilization. To produce foams having a relatively small pore size and a relatively high material density, the comminuted SIS may be tightly compacted by removing the water in a substantially uniform manner so as to achieve a relatively high density. Thereafter, the comminuted SIS is flash-frozen using liquid nitrogen prior to lyophilization of the SIS. To produce foams having a moderate pore size and a moderate material density, the comminuted SIS is first tightly compacted by removing the water in a substantially uniform manner so as to achieve a relatively high density. Thereafter, the SIS is frozen at a relatively fast rate (e.g., >−1° C./min) to a temperature of about −80° C. prior to lyophilization of the SIS.
• Additional techniques for forming such SIS foams in varying pore sizes and material densities are further described in copending U.S. patent application Ser. No. 10/195,354 entitled “Porous Extracellular Matrix Scaffold and Method” (Attorney Docket No. 265280-71146, DEP-747), the disclosure of which is hereby incorporated by reference.
• In any case, once theplug26 is fabricated, it is secured to theanchor12. To do so, theplug26 may be secured to theanchor12 in a number of different manners. For example, theplug26 may be secured to theanchor12 by virtue of the lyophilization process. Alternatively, theplug26 may be mechanically secured to theanchor12 such as by the use of sutures or an adhesive. Theplug26 could also be captured between parts of theanchor12. Crosslinking could also be used to secure the plug to the anchor.
• Referring now toFIG. 2, there is shown another embodiment of a cartilage repair device (hereinafter referred to with reference numeral110). Thecartilage repair device110 is somewhat similar to thecartilage repair device10. As such, the same reference numerals are utilized inFIG. 2 to identify components which have previously been discussed, with additional discussion thereof being unwarranted. In addition to theanchor12 and theplug26, thecartilage repair device110 includes acover34. Thecover34 may assume many different configurations, one of which being a number ofsheets28. Thecover34 is configured to have the structural integrity necessary to bear the forces associated with articulation with the other bone.
• The cover34 (e.g., the sheets28) may also be utilized to secure theplug26 to theanchor12. In particular, as shown inFIG. 2, thesheets28 may be wrapped around theplug26 and thehead portion22 of theanchor12.
• The cover34 (e.g., the sheets28) may be constructed of the same or different ECM material as the plug26 (e.g., SIS) and may be perforated to allow easy chemical and cellular transfer. Thecover34 could also be made of a synthetic biocompatible polymer. The cover34 (e.g., the sheets28) may be attached to theanchor12 either by virtue of the lyophilization process or may be mechanically secured to theanchor12 such as by the use of sutures or an adhesive. Thecover34 may also be chemically or physically crosslinked in a similar manner to as described above in regard to theplug26. Moreover, bioactive agents, biologically derived substances (e.g. stimulants), cells, biological lubricants, and/or biocompatible inorganic materials as defined above, may be added to thesheets28.
• To produce the desired structural rigidity, the naturally occurring ECM material from which the cover34 (e.g., the sheets28) is constructed may be fabricated in a manner similar to as described above in regard to theanchor12 or theplug26. Alternatively, thecover34 may compriselayers28 of material like the commercially available RESTORE product available from DePuy Orthopaedics of Warsaw, Ind. that have been hardened. Thecover34 may also comprise a mixture or composite of materials. For example, thecover34 could comprise layers of both polymer and ECM material.
• In an exemplary example of the embodiment ofFIG. 2, theanchor12 may be constructed of PLLA, theplug26 made of a cross-linked SIS foam material, and thecover34 made of layers of SIS material like the commercially available RESTORE product that has been hardened. Thecover34 can also comprise an element shaped like the upper component82 of the scaffold fixation device illustrated in FIGS. 7-9 and 11-13 of U.S. Pat. No. 6,371,958 B1, the complete disclosure of which is incorporated by reference herein.
• Referring now toFIG. 3, there is shown another embodiment of a cartilage repair device (hereinafter referred to with reference numeral210). Thecartilage repair device210 is somewhat similar to thecartilage repair devices10 and110. As such, the same reference numerals are utilized inFIG. 3 to identify components which have previously been discussed, with additional discussion thereof being unwarranted. Thecartilage repair device210 utilizes a number of theECM sheets28 as a chondrogenic growth supporting matrix. As such, thesheets28 of ECM material function as a “plug” in a similar manner as theplug26. As shown inFIG. 3, thesheets28 are secured to theanchor12 by wrapping thesheets28 around thehead portion22 of theanchor12.
• Similarly to as described above, thesheets28 of ECM material of thecartilage repair device210 may be perforated to allow easy chemical and cellular transfer. In addition to wrapping, thesheets28 may be further secured to theanchor12 either by virtue of the lyophilization process or may be mechanically secured to theanchor12 such as by the use of sutures or an adhesive. Thesheets28 may also be chemically crosslinked. Moreover, bioactive agents, biologically derived substances (e.g. stimulants), biological lubricants, cells, and/or biocompatible inorganic materials as defined above may be added to thesheets28.
• Referring now toFIG. 4, there is shown another embodiment of a cartilage repair device (hereinafter referred to with reference numeral310). Thecartilage repair device310 is somewhat similar to thecartilage repair devices10,110, and210. As such, the same reference numerals are utilized inFIG. 4 to identify components which have previously been discussed, with additional discussion thereof being unwarranted. Thecartilage repair device310 is essentially the same as thecartilage repair device110 ofFIG. 2, except for the configuration of thecover34. In particular, the cover34 (in this case, thesheets28 of naturally occurring ECM material) does not wrap around the edges of the plug26 (as does thecover34 ofFIG. 2). In such a configuration, theporous plug26 is, in effect, sandwiched between a top cover and a bottom cover. Thesheets28 of thecartilage repair device310, which in this exemplary embodiment function as thecover34, may be constructed of the same or different ECM material as the plug26 (e.g., SIS) and may be perforated to allow easy chemical and cellular transfer. Thesheets28 may be attached to theanchor12 and/or theplug26 either by virtue of the lyophilization process or may be mechanically secured to theanchor12 and/or theplug26 such as by the use of sutures or an adhesive. As described above, the cover34 (e.g., the sheets28) of thecartilage repair device310 may also be chemically crosslinked. Moreover, bioactive agents, biologically derived substances (e.g. stimulants), cells, biological lubricants, biocompatible polymers and/or biocompatible inorganic materials as defined above may be added to thecover34. Yet further, thecover34 of thecartilage repair device310 may also be cured or otherwise fabricated to produce a structure with a desired structural rigidity.
• Referring now toFIG. 5, there is shown another embodiment of a cartilage repair device (hereinafter referred to with reference numeral410). Thecartilage repair device410 is somewhat similar to thecartilage repair devices10,110,210, and310. As such, the same reference numerals are utilized inFIG. 5 to identify components which have previously been discussed, with additional discussion thereof being unwarranted. Thecartilage repair device410 includes ananchor412 which is utilized in lieu of theanchor12 described in regard toFIGS. 1-4. In particular, in the embodiment shown inFIG. 5, theplug26 is positioned in anosteochondral defect414 without the use a bottom-mounted anchor (i.e., theanchor12 ofFIGS. 1-4). Similarly to as described above, theplug26 is constructed out of comminuted and lyophilized naturally occurring ECM (e.g., SIS) having a desired porosity and material density.
• Theplug26 is retained in the hole formed in thecartilage16 and protected from in vivo forces by an annular shapedanchor412. Theanchor412 may be provided in many different configurations which allow it to be press fit or otherwise anchored into thesubchondral bone18. For example, as shown inFIG. 5, theanchor412 may be “bottle cap”-shaped so as to allow theanchor412 to be press fit or otherwise secured into anannular groove416 formed in thesubchondral bone18. The groove may be formed and the anchor may be shaped as described and shown in Patent Cooperation Treaty publication WO 01/39694 A2, published 7 Jun. 2001 entitled “Fixation Technology”, the complete disclosure of which is incorporated by reference herein. Alternatively, theanchor412 may be mechanically secured to thesubchondral bone18 by use of adhesive or other types of anchoring structures (e.g., barbs).
• Theanchor412 of thecartilage repair device410 may be constructed from numerous types of synthetic or naturally occurring materials. For example, theanchor12 may be constructed with a bioabsorbable polymer such as PLLA, PGA, PDO, PCL, or any other such bioabsorbable polymer which is commonly utilized in the construction of prosthetic implants. Moreover, theanchor412 may be constructed from a naturally occurring material such as a naturally occurring ECM (e.g., SIS) which is cured or otherwise fabricated to be rigid and hardened to facilitate attachment to the bone in the same manner as described above in regard to theanchor12 and/or theplug26 ofFIGS. 1-4.
• In the case of when theanchor412 is constructed from ECM, one or more laminated ornon-laminated sheets28 of the same or different ECM may be utilized. Thesheets28 may surround theplug26 on three sides, or perhaps all four sides. Alternatively, the anchor may be constructed from formed (e.g., dried and machined) comminuted ECM material. In either configuration, the ECM material may be perforated and may be cured in a similar manner to as described above in regard to theanchor12 or theplug26. As with the ECM material previously described above, the ECM material from which theanchor412 is constructed may also be chemically crosslinked. Moreover, bioactive agents, biologically derived substances (e.g. stimulants), cells, biocompatible polymers, biocompatible inorganic materials, and/or biological lubricants as defined above may be added to the ECM material utilized to construct theanchor412.
• Referring now toFIG. 6, there is shown another embodiment of a cartilage repair device (hereinafter referred to with reference numeral510). Thecartilage repair device510 is somewhat similar to thecartilage repair devices10,110,210,310, and410. As such, the same reference numerals are utilized inFIG. 6 to identify components which have previously been discussed, with additional discussion thereof being unwarranted.
• Thecartilage repair device510 includes ananchor512 which is somewhat similar to theanchor412 described in regard toFIG. 5. In particular, in the embodiment shown inFIG. 6, theplug26 is positioned in the hole formed in thecartilage16 without the use a bottom-mounted anchor (i.e., theanchor12 ofFIGS. 1-4). However, in the case of thecartilage repair device510 ofFIG. 6, theanchor512 is configured as a staple520 which secures the plug within thedefect514.
• Similarly to as described above, in this embodiment, theplug26 may be constructed from comminuted and lyophilized naturally occurring ECM (e.g., SIS) having a desired porosity and material density. As shown inFIG. 6, theplug26 may be wrapped in acover34 such as a number ofsheets28 of the same or different ECM which surround theplug26. It should be appreciated that in a similar manner to thecartilage repair device210 ofFIG. 3, in lieu of aseparate plug26, thesheets28 of ECM material themselves may function as a chondrogenic growth supporting matrix.
• The wrapped plug26 (or similar matrix formed from the sheets28) is retained in thedefect514 by inserting the staple520 into thesubchondral bone18. Alternatively, the wrapped plug26 (or similar matrix formed from the sheets28) may be press fit or adhesively secured in thedefect514. In the case of a press fit plug, one or more grooves may be formed in thesheets28 to facilitate the press fit process.
• Thestaple520 of thecartilage repair device510 may be constructed of numerous types of synthetic or naturally occurring materials. For example, thestaple520 may be constructed from a bioabsorbable polymer such as PLLA, PGA, PDO, PCL, or any other such bioabsorbable polymer which is commonly utilized in the construction of prosthetic implants. Moreover, thestaple520 may be constructed from a naturally occurring material such as a naturally occurring ECM (e.g., SIS) which is cured to be rigid and hardened to facilitate attachment to the bone in the same manner as described above in regard to theanchor12 ofFIGS. 1-4 and theanchor412 ofFIG. 5.
• The staple520 can comprise a commercially available product, such as a staple available from the MITEK® Products division of ETHICON, INC. of Westwood, Mass. Moreover, thestaple520 may be embodied as any of the staples or other devices and methods disclosed in U.S. Pat. No. 6,179,840 issued Jan. 30, 2001; U.S. Pat. No. 6,364,884 issued Apr. 2, 2002; U.S. patent application Ser. No. 09/535,183 entitled “Graft Fixation Device Combination” which was filed on Mar. 27, 2000; U.S. patent application Ser. No. 09/535,189 entitled “Instrument for Inserting Graft Fixation Device” which was filed on Mar. 27, 2000; U.S. patent application Ser. No. 09/793,036 entitled “Graft Fixation Device Combination” which was filed Feb. 26, 2001; U.S. patent application Ser. No. 09/793,043 entitled “Methods of Securing a Graft Using a Graft Fixation Device” which was filed on Feb. 26, 2001; U.S. patent application Ser. No. 09/793,216 entitled “Instrument for Inserting Graft Fixation Device” which was filed on Feb. 26, 2001; U.S. patent application Ser. No. 09/864,619 entitled “Graft Fixation Device and Method” which was filed on May 24, 2001; U.S. patent application Ser. No. 10/056,534 entitled “Graft Fixation Device Combination” which was filed on Jan. 24, 2002; and U.S. patent application Ser. No. 10/142,399 entitled “Graft Fixation Device Combination” which was filed on May 9, 2002, the disclosures of each of these patents and patent applications being hereby incorporated by reference.
• Referring now toFIG. 7, there is shown another embodiment of a cartilage repair device (hereinafter referred to with reference numeral610). Thecartilage repair device610 is somewhat similar to thecartilage repair devices10,110,210,310,410, and510. As such, the same reference numerals are utilized inFIG. 7 to identify components which have previously been discussed, with additional discussion thereof being unwarranted.
• Thecartilage repair device610 includes ananchor612 which, similarly to the other anchors described herein, is utilized to retain theplug26 in anosteochondral defect614. In the embodiment shown inFIG. 7, theanchor612 is configured as aring620 which supports and secures theplug26 within thedefect614.
• Similarly to as described above, theplug26 utilized in this, or any other embodiment described herein, may be constructed out of comminuted and lyophilized naturally occurring ECM (e.g., SIS) having a desired porosity and material density. As shown inFIG. 7, theplug26 may be wrapped in acover34 such as a number ofsheets28 of the same or different ECM material. It should be appreciated that in a similar manner to thecartilage repair device210 ofFIG. 3, in lieu of aseparate plug26, thesheets28 of ECM material may themselves function as a chondrogenic growth supporting matrix.
• The wrapped plug26 (or the matrix formed from the sheets28) is supported and retained in the hole formed in thecartilage16 by inserting thering620 into the hole. As shown inFIGS. 8-10, thering620 may be embodied as a closed ring (seeFIG. 8), a ring formed with a slot (seeFIG. 9), or a ring formed with a taper (seeFIG. 10). Such modifications may be utilized to enhance the retention characteristics of thering620 in a given application.
• Thering620 of thecartilage repair device610 may be constructed of numerous types of synthetic or naturally occurring materials. For example, thering620 may be constructed with a bioabsorbable polymer such as PLLA, PGA, PDO, PCL, or any other such bioabsorbable polymer which is commonly utilized in the construction of prosthetic implants. Moreover, thering620 may be constructed with a naturally occurring material such as a naturally occurring ECM (e.g., SIS) which is cured to be rigid and hardened in the same manner as described above in regard to theanchor12 ofFIGS. 1-4 and theanchors412 and512 ofFIGS. 5 and 6, respectively. The inner space defined by thering620 may be filled with material, such as ECM material (e.g., SIS), subsequent to implantation of thering620.
• Referring now toFIGS. 11-13, there is shown another embodiment of a cartilage repair device (hereinafter referred to with reference numeral710). Thecartilage repair device710 is somewhat similar to thecartilage repair devices10,110,210,310,410,510, and610. As such, the same reference numerals are utilized inFIGS. 11-13 to identify components which have previously been discussed, with additional discussion thereof being unwarranted.
• Thecartilage repair device710 includes ananchor712 which, similarly to the other anchors described herein, is utilized to retain theplug26 in anosteochondral defect714. In the embodiment shown inFIGS. 11-13, theanchor712 is configured as aring720 which has a number ofbarbs722 extending radially outwardly from a center of thering720. In particular, thering720 includes aring body724 and a number oftubes726. Afirst end portion728 of each of thetubes726 is positioned near the center point of thering body724, whereas asecond end portion730 of each of thetubes726 extends through thering body724.
• One of the barbs722 (or other type of engagement member) is positioned in each of thetubes726. Each of thebarbs722 has afirst end734 which is extendable out of thefirst end portion728 of thetube726, and asecond end736 which is extendable out of thesecond end portion730 of thetube726. Thesecond end736 of thebarbs722 has a tip, point, or other type of engagement feature defined therein.
• Each of thebarbs722 is positionable in either an extended position (as shown inFIGS. 12 and 13) or a retracted position (as shown inFIG. 11). When positioned in its extended position, thepointed end736 of thebarb722 extends out of the outer end of thetube726 in which it is positioned (seeFIGS. 12 and 13). Conversely, when positioned in its retracted position, thepointed end736 of thebarb722 is retracted or otherwise received into the outer end of thetube726 in which it is positioned (seeFIG. 11).
• Thebarbs722 may be selectively moved from their retracted positions to their extended positions subsequent to positioning thering720 in the defect. In particular, as shown inFIG. 11, theinner end734 of thebarbs722 has a cam surface738 defined therein. In such a way, engagement of the cam surfaces738 by a complimentary cam surface of an engagement tool (not shown) urges thebarbs722 radially outwardly thereby moving thebarbs722 from their respective retracted positions to their respective extended positions. In an exemplary embodiment, the engagement tool has a spheroid-shaped engagement surface which, upon contact with the cam surfaces738 of thebarbs722, urges thebarbs722 radially outwardly.
• Similarly to as described above, theplug26 utilized in this, or any other embodiment described herein, may be constructed out of comminuted and lyophilized naturally occurring ECM (e.g., SIS) having a desired porosity and material density. As shown inFIGS. 12 and 13, theplug26 may be wrapped in acover34 such as a number ofsheets28 of the same or different ECM material. It should be appreciated that in a similar manner to thecartilage repair device210 ofFIG. 3, in lieu of aseparate plug26, thesheets28 of ECM material may themselves function as a chondrogenic growth supporting matrix.
• The wrapped plug26 (or the matrix formed from the sheets28) is supported and retained in the hole formed in thecartilage16 by inserting thering720 into the hole, and thereafter engaging thesidewall740 in which the hole is formed with thebarbs722. In particular, once positioned in the hole, thebarbs722 may be urged from their retracted positions to their extended positions thereby causing the pointed ends736 of thebarbs722 to engage thesidewall740.
• As shown inFIG. 12, the surgical site may be prepared such that thering720, when implanted, engages thenative cartilage16. Alternatively, as shown inFIG. 13, the surgical site may be prepared such that thering720, when implanted, engages thesubchondral bone18.
• Thering720 of thecartilage repair device710 may be constructed of numerous types of synthetic or naturally occurring materials. For example, thering720 may be constructed with a bioabsorbable polymer such as PLLA, PGA, PDO, PCL, or any other such bioabsorbable polymer which is commonly utilized in the construction of prosthetic implants.
• Moreover, thering720 may be constructed with a naturally occurring material such as a naturally occurring ECM (e.g., SIS) which is cured to be rigid and hardened in the same manner as described above in regard to theanchor12 ofFIGS. 1-4 and theanchors412 and512 ofFIGS. 5 and 6, respectively. The ECM material may be perforated and may be cured in a similar manner to as described above in regard to theanchor12 or theplug26. As with the ECM material previously described above, the ECM material from which thering720 is constructed may also be chemically crosslinked. Moreover, bioactive agents, biologically derived substances (e.g. stimulants), cells, biocompatible polymers, biocompatible inorganic materials, and/or biological lubricants as defined above may be added to the ECM material utilized to construct thering720.
• The principles of the present disclosure may also be applied to other types of anchors. For example, cartilage repair units like those disclosed in U.S. Pat. No. 5,769,899 to Schwartz et al., the disclosure of which is incorporated by reference herein, can be made with a plug of naturally occurring extracellular matrix, with or without a cover. In addition, cartilage repair units like those disclosed in U.S. Pat. No. 6,251,143 B1 to Schwartz et al., the disclosure of which is incorporated by reference herein, can be made with an insert of naturally occurring extracellular matrix, with or without a cover. Reference is also made to U.S. Pat. No. 6,371,958 B1, discussed above; the entire scaffold fixation device could be made of naturally occurring extracellular matrix.
• Hence, the cartilage repair devices described herein have numerous advantages over heretofore designed devices. In particular, heretofore designed devices use, primarily, synthetic polymeric materials. However, synthetic polymers do not possess the advantages naturally occurring extracellular matrices (ECMs), like SIS, which can inherently stimulate cells to proliferate and to synthesize new tissue. However, one or both of the plug and the anchor of the cartilage repair devices described herein may be constructed out of a naturally occurring ECM material such as SIS. Such a device provides an enhanced structure into which cells migrate, proliferate, and synthesize new tissue. Moreover, such a device also possess sufficient mechanical strength and degradation kinetics to successfully withstand in vivo joint forces at least initially following implantation. In addition, for use in combination with devices such as the scaffold fixation device disclosed in U.S. Pat. No. 6,371,958 B1, the plug should possess sufficient mechanical strength and degradation kinetics to successfully withstand the load provided by the anchoring device.
• The concepts disclosed in the following copending U.S. patent applications, which are incorporated by reference herein, may be combined with the teachings of the present disclosure: Ser. No. 10/195,795 entitled “Meniscus Regeneration Device and Method” (Attorney Docket No. 265280-71141, DEP-745); Ser. No. 10/195,719 entitled “Devices from Naturally Occurring Biologically Derived Materials” (Attorney Docket No. 265280-71142, DEP-748); Ser. No. 10/195,344 entitled “Unitary Surgical Device and Method” (Attorney Docket No. DEP-750); Ser. No. 10/195,341 entitled “Hybrid Biologic/Synthetic Porous Extracellular Matrix Scaffolds” (Attorney Docket No. 265280-71144, DEP-751); Ser. No. 10/195,606 entitled “Cartilage Repair and Regeneration Device and Method” (Attorney Docket No. 265280-71145, DEP-752); Ser. No. 10/195,354 entitled “Porous Extracellular Matrix Scaffold and Method” (Attorney Docket No. 265280-71146, DEP-747); Ser. No. 10/195,334 entitled “Cartilage Repair and Regeneration Scaffolds and Method” (Attorney Docket No. 265280-71180, DEP-763); and Ser. No. 10/195,633 entitled “Porous Delivery Scaffold and Method” (Attorney Docket No. 265280-71207, DEP-762), along with U.S. patent application Ser. No. 10/172,347 entitled “Hybrid Biologic-Synthetic Bioabsorbable Scaffolds” which was filed on Jun. 14, 2002. For example, it may be desirable to use biological lubricants in combination with the concepts of the present disclosure.
• For some cartilage repair applications, a repair may be made with a RESTORE™ wafer from DePuy Orthopaedics, Inc. which is seeded with cells to encourage the healing process. For example, RESTORE™ wafers may be seeded with cells supplied by Verigen Transplantation Service International AG (VTSI) in Germany in accordance with processes offered by VTSI. See U.S. Pat. Nos. 6,379,367 and 6,283,980, incorporated by reference herein. Illustratively, a 1.5 cm RESTORE™ wafer, which is typically made by laminating ten layers of SIS together, is supplied to VTSI to be seeded with cells.
• Illustratively, therefore, a cartilage implant may comprise a laminate of a plurality of layers of ECM such as SIS, which laminate is seeded with cells such as chondrocyte cells.
• While the concepts of the present disclosure have been illustrated and described in detail in the drawings and foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only the illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected.
• There are a plurality of advantages of the present disclosure arising from the various features of the cartilage repair devices described herein. It will be noted that alternative embodiments of each of the cartilage repair devices of the present disclosure may not include all of the features described yet benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of cartilage repair devices that incorporate one or more of the features of the present disclosure and fall within the spirit and scope of the appended claims.

Claims (23)

1. A device for repairing a diseased or damaged portion of articular cartilage on a bone of a joint, the cartilage having been prepared by forming an opening therein to remove the diseased or damaged portion, the device comprising:

a plug configured to be positioned in the opening formed in the cartilage, the plug defining a body of unseeded naturally occurring extracellular matrix, and

an anchor configured to position and hold the plug in the opening.

2. The device ofclaim 1, wherein the naturally occurring extracellular matrix comprises comminuted naturally occurring extracellular matrix.

3. The device ofclaim 2, wherein the comminuted naturally occurring extracellular matrix is lyophilized.

4. The device ofclaim 1, wherein the naturally occurring extracellular matrix comprises tissue selected from the group consisting of: vertebrate small intestine submucosa; vertebrate liver basement membrane; vertebrate bladder submucosa; vertebrate stomach submucosa; vertebrate alimentary tissue; vertebrate respiratory tissue; and vertebrate genital tissue.

5. The device ofclaim 4, wherein the naturally occurring extracellular matrix comprises tissue selected from the group consisting of: bovine tissue; ovine tissue; and porcine tissue.

6. The device ofclaim 1, wherein the anchor is formed of naturally occurring extracellular matrix cured and shaped to fasten into a subchondral portion of the bone.

7. The device ofclaim 6, wherein the anchor comprises (i) a head portion configured to support the plug, and (ii) a body portion extending from the head portion to fasten into the subchondral portion of the bone.

8. The device ofclaim 1, further comprising a cover disposed over at least part of an articular surface of the plug, wherein the cover comprises one or more sheets of naturally occurring extracellular matrix.

9. A device for repairing a diseased or damaged portion of articular cartilage on a bone of a joint, the cartilage having been prepared by forming an opening therein to remove the diseased or damaged portion, the device comprising:

a plug configured to be positioned in the opening formed in the cartilage, the plug defining a body of naturally occurring extracellular matrix seeded with at least one of the following: a bioactive agent, a biologically derived substance, cells, a biological lubricant, a biocompatible polymer and a biocompatible inorganic material, and

an anchor configured to position and hold the plug in the opening.

10. The device ofclaim 9, wherein the naturally occurring extracellular matrix comprises comminuted naturally occurring extracellular matrix.

11. The device ofclaim 10, wherein the comminuted naturally occurring extracellular matrix is lyophilized.

12. The device ofclaim 9, wherein the naturally occurring extracellular matrix comprises tissue selected from the group consisting of: vertebrate small intestine submucosa; vertebrate liver basement membrane; vertebrate bladder submucosa; vertebrate stomach submucosa; vertebrate alimentary tissue; vertebrate respiratory tissue; and vertebrate genital tissue.

13. The device ofclaim 12, wherein the naturally occurring extracellular matrix comprises tissue selected from the group consisting of: bovine tissue; ovine tissue; and porcine tissue.

14. The device ofclaim 9, wherein the anchor is formed of naturally occurring extracellular matrix cured and shaped to fasten into a subchondral portion of the bone.

15. The device ofclaim 14, wherein the anchor comprises (i) a head portion configured to support the plug, and (ii) a body portion extending from the head portion to fasten into the subchondral portion of the bone.

16. The device ofclaim 9, further comprising a cover disposed over at least part of an articular surface of the plug, wherein the cover comprises one or more sheets of naturally occurring extracellular matrix.

17. A device for repairing a diseased or damaged portion of articular cartilage on a bone of a joint, the cartilage having been prepared by forming an opening therein to remove the diseased or damaged portion, the device comprising:

a plug configured to be positioned in the opening formed in the cartilage, wherein (i) the plug comprises naturally occurring extracellular matrix, and (ii) the plug has an outer articular surface and one or more side surfaces extending therefrom,

an anchor configured to position and hold the plug in the opening, and

a cover disposed over at least part of the articular surface of the plug, wherein the cover comprises one or more sheets of naturally occurring extracellular matrix.

18. The device ofclaim 17, wherein the naturally occurring extracellular matrix comprises comminuted naturally occurring extracellular matrix.

19. The device ofclaim 17, wherein the comminuted naturally occurring extracellular matrix is lyophilized.

20. The device ofclaim 17, wherein the naturally occurring extracellular matrix comprises tissue selected from the group consisting of: vertebrate small intestine submucosa; vertebrate liver basement membrane; vertebrate bladder submucosa; vertebrate stomach submucosa; vertebrate alimentary tissue; vertebrate respiratory tissue; and vertebrate genital tissue.

21. The device ofclaim 20, wherein the naturally occurring extracellular matrix comprises tissue selected from the group consisting of: bovine tissue; ovine tissue; and porcine tissue.

22. The device ofclaim 17, wherein the anchor is formed of naturally occurring extracellular matrix cured and shaped to fasten into a subchondral portion of the bone.

23. The device ofclaim 22, wherein the anchor comprises (i) a head portion configured to support the plug, and (ii) a body portion extending from the head portion to fasten into the subchondral portion of the bone.

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