DE69623112T2 - Cartilage repair unit - Google Patents

Abstract

This invention is a bio-absorbable cartilage repair system (12) for regenerating damaged or destroyed articular cartilage on the surface of a bone by establishing chondrogenic growth supporting matrix between an area of removed damaged or destroyed articular cartilage and the adjacent healthy cancellous bone. The system (12) is at least one assembly of a bio-absorbable delivery unit (14), configured and dimensioned to be mounted in both the removed area and the adjacent healthy area, and a porous bio-absorbable insert (16) supported by and in the delivery unit (14) and establishing communication between the removed area and the adjacent healthy area for a chondrogenic growth supporting matrix. The insert (16) preferably includes a repair factor (e.g., a growth factor, an attachment factor, or both) releasably disposed in the insert (16) to assist in establishing the chondrogenic growth supporting matrix.

Description

BACKGROUND OF THE INVENTION

This invention relates to a bio-absorbable cartilage repair system for regenerating articular cartilage, and more particularly to a system that allows vascular penetration and cell migration between the system and the adjacent healthy area of articular cartilage and cancellous bone, thereby resulting in regeneration of the damaged articular cartilage.

Articular cartilage on the surface of bones in joints, especially knee and hip joints, is subject to deterioration caused by injury or disease. This deterioration of the cartilage leads to pain and ultimately loss of joint movement and severe pain. As a result, various procedures have been developed to treat and repair damaged or destroyed articular cartilage.

Prosthetic devices are often used to replace damaged or destroyed articular cartilage. For example, US Patent No. 4,627,853 discloses prostheses used to replace articular cartilage. The prostheses are made by demineralizing a bone segment, with the demineralized bone segment serving as a replacement for articular cartilage.

US Patent No. 4,880,429 discloses a meniscus prosthesis that is implanted in the knee. The meniscus prosthesis acts as a scaffold for regrowth of native meniscus tissue and comprises collagen fibers interspersed with glycoaminoglycan molecules.

US Patent No. 5,176,710 discloses a prosthesis for replacing bone material on the articular surface of a joint. The prosthesis has a specific elastic modulus to provide stiffness to the prosthesis and includes concave shapes suitable for biological ingrowth.

US Patent No. 4,502,161 discloses a meniscus prosthesis that replaces the natural meniscus between the articular surfaces of the bones and joints and includes an insert and an extension for attachment to the bone and a reinforcing fabric or mesh embedded therein.

US Patent No. 3,745,590 discloses a prosthesis for repairing or replacing joints, the prosthesis comprising a body part including a stem and ligament elements and allowing tissue ingrowth.

US Patent No. 5,123,927 discloses a knee prosthesis comprising a bone cement containing an antibiotic.

Although there are several prosthetic devices that can be used to replace damaged or destroyed tissue cartilage, prosthetic devices have several disadvantages. For example, cements used to attach prosthetic devices to bone can loosen and eventually fail. Additionally, fragmented cement can migrate into the joints and associated lymphatic tissue, causing inflammation and further damage. In addition, cements lead to the formation of fibrous tissue between the bone and the prosthesis. Another major disadvantage associated with the use of a prosthesis is that the prosthetic device can be larger than the damaged cartilage to be replaced, thereby requiring removal of portions of healthy bone and/or cartilage to accommodate the prosthetic device. Therefore, the need remains for a system for repairing and regenerating articular cartilage that avoids the problems associated with prosthetic devices.

Another means used to treat damaged articular cartilage is the introduction of repair patches onto the bone, with the repair patches replacing excised pieces of cartilage. For example, US Patent No. 5,067,964 discloses an articular cartilage repair patch comprising a layer of felted, fibrous nonwoven material that is pliable and readily conformable to flat and curved surfaces. The tissue cartilage repair patch is attached to the bone by, for example, bio-absorbable screws or pins or similar temporary fixation techniques. Ingrown fibrous tissue eventually surrounds the repair patch, causing the repair patch to permanently attach to the bone. Although US Patent No. 5,067,964 discloses an alternative discloses a method for repairing damaged articular cartilage; it does not disclose a means or method for regenerating damaged or destroyed articular cartilage. Therefore, a need remains for a system for regenerating damaged or destroyed articular cartilage in which the regenerated articular cartilage is functionally similar to undamaged articular cartilage.

US 5,306,311-A a discloses a cartilage repair system in accordance with the preamble of claim 1. In such an arrangement, a carrier for insertion into subchondral bone carries an insert of porous bio-absorbable material into an area from which damaged or destroyed articular cartilage has been removed.

Although the insert can be placed in direct contact with adjacent healthy articular cartilage, the arrangement does not provide a connection between the insert and the healthy cancellous bone within which the insert is located because the carrier itself represents a boundary between the cancellous bone and the insert.

It is an object of the invention to provide a system for regenerating articular cartilage in which the regenerated articular cartilage is superior to fibrous or fibrocartilaginous repairs and is functionally similar to undamaged articular cartilage.

A further objective is to provide a cartilage repair system for use in regenerating damaged or destroyed articular cartilage.

Yet another object of the present invention is to provide an embodiment of a cartilage repair system that does not utilize cement or non-bioabsorbable prosthetic devices.

These objects are solved by the characterizing features of claim 1.

In a preferred embodiment, the insert includes a repair factor releasably disposed in the insert to assist in producing the chondrogenic growth-supporting matrix. The repair factor may be a growth factor, preferably one selected from the group consisting of fibroblast growth factor, transforming Growth factor beta, insulin, insulin-like growth factor, platelet-derived growth factor, and combinations thereof. Alternatively, the repair factor may be a binding factor, preferably one selected from the group consisting of fibronectin, RGD polypeptide, and combinations thereof. Indeed, the repair factor preferably includes both growth and binding factors.

The cartilage repair system typically comprises a plurality of the aforementioned assemblies, wherein the delivery units of the assemblies are disposed between the bone and the remote area, and wherein the inserts of the assemblies produce the chondrogenic growth-supporting matrix over a substantial portion of the remote area. Preferably, the delivery units of the assemblies are polygonal in their configuration and fit.

In another preferred embodiment, the insert consists essentially of a bio-absorbable material selected from the group consisting of hyaluronic acid, polyglycolic acid, polylactic acid, fibrin islands, periosteal cells, polydioxane, polyester, alginate and combinations thereof, while the delivery unit comprises a bio-absorbable material selected from the group consisting of hyaluronic acid, polyglycolic acid, polylactic acid, alginate and combinations thereof. Preferably, the delivery unit is integrally molded and defines channels to allow vascular penetration and cell migration to an adjacent surface of the insert.

The cartilage repair system preferably includes means for precluding relative rotation of the delivery unit and the insert in the delivery unit.

The present invention further includes a cartilage repair system adapted for placement on a bone surface to produce a chondrogenic, growth-supporting matrix, the system comprising a bio-absorbable delivery unit configured and dimensioned to be placed on the bone, the unit including a support frame and means for mounting the unit in the bone, and a porous, bio-absorbable insert supported by the support frame to provide a chondrogenic, growth-supporting matrix.

In a preferred embodiment, the insert includes a repair factor releasably disposed in the insert to enhance the chondrogenic growth-supporting matrix. The support frame is designed to allow vascular ingress and cell migration to the insert. Therefore, the support frame preferably has an open top, a bottom defining a plurality of channels to allow vascular ingress and cell migration to the bottom of the insert, and optionally side walls defining windows through which the insert extends to allow cell migration to the sides of the insert through an adjacent healthy area of articular cartilage. The unit and the insert define an assembly, and the system preferably consists of a plurality of assemblies in adjacent and contiguous fashion. The unit is preferably more rigid than the insert.

BRIEF DESCRIPTION OF THE DRAWINGS

The above brief description, as well as other objects, features and advantages of the present invention, will be more fully understood by reference to the following detailed description of the presently preferred, though illustrative, embodiments of the present invention, taken in conjunction with the accompanying drawings, in which:

Figure 1 is a fragmentary schematic view of a knee having therein a pair of assemblies of the cartilage repair system according to the present invention;

Fig. 2 is an exploded isometric view of an assembly of the cartilage repair system;

Fig. 3 is a top plan view thereof;

Fig. 4 is a side view thereof;

Fig. 5 is a cross-sectional view thereof taken along line 5-5 of Fig. 3 and showing in fragmentary form the cartilage repair system deployed in a bone; and

Fig. 6 is a cross-sectional view thereof taken along line 6-6 of Fig. 5, with potentially adjacent arrangements fragmentarily shown in phantom.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, and in particular to Fig. 1, there is illustrated a cartilage repair system according to the present invention, generally designated by the reference numeral 10. In particular, the cartilage repair system 10 shown in Fig. 1 comprises a plurality of assemblies, generally designated 12 (two of which are shown, but it is understood that the number required will be determined by the extent of the damaged area). Each assembly 12 in turn comprises a bio-absorbable delivery unit 14 and a porous bio-absorbable insert 16. The delivery unit 14 is configured and dimensioned so that it can be applied both to the area from which damaged or destroyed articular cartilage has been removed and to the adjacent healthy cancellous bone area of the bone. The porous insert 16 is carried by and within the delivery unit 14 and provides a connection between the removed area (i.e., the area from which the damaged or destroyed articular cartilage has been removed) and the adjacent healthy area for a chondrogenic growth-supporting matrix, thereby promoting vascular penetration and cell migration to achieve articular cartilage regeneration.

While the system 10 is illustrated in Fig. 1 as being used to regenerate damaged or destroyed articular cartilage on the femoral knee joint surface K, those skilled in the medical arts will readily recognize that the system 10 is equally useful in other joints such as the shoulder, hip, and the like. The extent of the damaged or destroyed articular cartilage on the surface of the bone will determine whether the system 10 utilizes a single array 12 or a plurality of arrays 12. The illustrated arrays 12 (and in particular the delivery units 14 thereof) are polygonal in plane and nestable -- that is, arranged so that they can preferably be mounted side by side in abutting abutting contact. The polygonal nature of the perimeter of the arrays allows for the arrays 12 to be fitted (as generally illustrated in Figure 6) and is thus preferred when a plurality of arrays 12 are to be used to completely cover a designated area of the bone. However, if only a single array 12 will be used, other configurations, such as a circular configuration, may be preferred.

While it might theoretically be possible to create a unitary, one-piece, integral assembly 12 in a single manufacturing process that performs the functions of both the delivery unit 14 and the insert 16, the present invention preferably uses two separate and independently formed components -- namely, the delivery unit 14 and the insert 16. As will be discussed in detail below, the inserts 16 can be made from a relatively wide variety of different materials and can even include a repair factor (such as a growth factor or a binding factor) releasably disposed therein to assist in creating the chondrogenic, growth-supporting matrix. Accordingly, the two-component nature of the assembly 12 of the present invention allows the insert 16 to be selected from a supply of different inserts 16 at the time of surgery to meet the individual needs of the patient at the time with respect to both the basic composition of the insert 16 and a repair factor composition therein. Again, due to the different types of insert 16 (and any repair factors therein) and its delivery unit 14, it may be necessary for certain types of inserts 16 to be stored in a different environment than the delivery units 14 prior to use -- for example, to allow for adequate preservation of the repair factor. Finally, the delivery unit 14 and the insert 16 of an assembly 12 must have different functional properties that would be difficult to achieve in an integral, one-piece, unitary element using known manufacturing techniques. Therefore, as will be discussed below, the delivery unit 14 must have sufficient strength and integrity to enable it to be pushed into the bone without significant bending or deformation, while the insert 16 is preferably a flexible and compliant porous material in the form of a matrix to enable it to be inserted into the delivery unit 14 and thereby provide a chondrogenic, growth-supporting matrix positioned by the delivery unit 14.

With particular reference to Figs. 2 and 5, the dispensing unit 14 comprises an upper cup-like support frame 22 and a lower T-like elongated component 23. The support frame 22 has an upper frame 24 defining an open upper end, side walls 26 and a bottom portion 30. The elongated component 23 (which is preferably cylindrical) extends downwardly from the bottom portion 30 (which is preferably concave) and has radially extending ribs 38, a blunt, sloped bottom 40 and a bore 42 (preferably about 1.5 mm in diameter) extending axially therethrough. The disk or waffle-like insert 16 has a top surface 52, side walls 54, a bottom surface 56 and a bore 58 (preferably about 1.5 mm in diameter) extending axially therethrough and, upon insertion into the dispensing unit 14, coaxial with the bore 42 thereof.

The support frame 22 of the dispensing unit 14 receives the insert 16 therein, with the side walls 26 of the support frame 22 receiving therein the side walls 54 of the insert 50. The bottom surface 56 of the insert 16 and the lower portion 30 of the support frame 22 are correspondingly shaped, preferably with the bottom surface of the insert 16 defining a protuberance and the upper surface of the bottom portion 30 defining a protuberance-receiving cavity, so that the two bores 42, 58 are automatically and precisely coaxially arranged after the insertion process. In other words, when the insert 16 is mounted in the support frame 22, the bore 42 through the extended member 23 and the bore 58 through the insert 16 are in vertically aligned abutting disposition.

As will be appreciated by those skilled in the implant art, if vascular penetration and cell migration between the healthy cancellous bone area and the area of removed damaged cartilage via the insert 16 is to be achieved, means must be provided to preclude relative rotation of the delivery unit 14 and the insert 16. This can be accomplished in a number of different ways.

First, as best seen in Figures 2-3 and 6, the outer periphery of the insert 16 and the inner periphery of the support frame 22 may be polygonal or irregular (i.e., non-circular) and sized to abut one another so that they are locked together for rotation only as a unit. For example, as illustrated, the hexagonal outer periphery of the insert 16 fits snugly within the hexagonal inner periphery of the support frame 22 to preclude relative rotation.

Second, the upper surface of the concave bottom portion 30 of the support frame 22 may define upwardly extending buttons 60 adjacent the side walls 26, while the lower surface of the insert 16 may define upwardly extending recesses 62 configured and dimensioned to receive the buttons 60, as best seen in Figs. 3 and 6. The number of buttons 60 and recesses 62, as well as the shape, size and arrangement thereof, are selected so that when the insert 16 is within the dispensing unit 14, the buttons 60 are precisely received in the recesses 62, so that the insert 16 and the dispensing unit 14 are precluded from relative rotation as long as the insert 16 is within the support frame 22.

Third, the side walls 54 of the insert 16 may define radially outwardly extending flanges 64, and the side walls 26 of the support frame 22 may define windows 66 therethrough that are configured and dimensioned to precisely receive the flanges 64 within or through them. The number of flanges 64 and windows 66, as well as the size, shape and spacing thereof, are selected such that when the insert 16 is within the support frame 22, relative rotation of the insert 16 and the dispensing unit 14 is precluded as long as the flanges 64 precisely extend into (and possibly through) the windows 66. In order to enable the insert 16 with its flanges 64 to be easily inserted into the support frame 22 with its windows 66, the insert 16 or at least the flanges 64 thereof are preferably resiliently movable. The flanges 64 or windows 66 may also have beveled edges to facilitate fitting of the flanges 64 into the windows 66 during the insertion process.

In the last two alternatives, the height of the buttons 60 and the depth of the recesses 62 or the relative heights of the flanges 64 and the windows 66 are selected so that the bottom surface 56 of the insert 16 will rest on the upper surface of the bottom portion 30 of the dispensing unit 14. It will be understood by those skilled in the art of mechanics that a wide variety of different key mechanisms well known in the art of mechanics can be used to preclude relative rotation of the insert 16 and the dispensing unit 14. It must be borne in mind, however, that with the present invention, over time the bio-absorbable elements -- that is, the dispensing unit 14 and the insert 16 -- will disappear as the human body hydrolyzes the material from which they are made. Accordingly, a selection must be made an appropriate key mechanism to preclude relative rotation of the insert 16 and the dispensing unit 14 in view of this circumstance. It will be understood that although for purposes of illustration a variety of different key mechanisms have been discussed in a single embodiment, in fact a single key mechanism may suffice for a particular embodiment, although a variety of such mechanisms may be used as well.

In order to enable the insert 16 to function as a chondrogenic growth-supporting matrix, it must provide access for vascular ingress and cell migration to regenerate the articular cartilage defect. Such access is provided at the inner periphery of the insert 16 through the bore 58. At the outer periphery of the insert 16, the windows 66 on the support frame 22 make direct contact with the adjacent healthy articular cartilage or adjacent repair structures. These windows 66 allow cell migration to occur to the insert. The entire upper surface 52 of the insert 16 is exposed to the articular environment of the affected joint, and a substantial portion of the bottom surface 56 of the insert 16 is exposed to the cancellous bone substance through channels 68 extending axially through the bottom 30 of the support frame 22. In providing communication between the area of removed damaged articular cartilage and the healthy cancellous bone or trabecular bone, the number of channels 68 as well as the size, shape and arrangement thereof are selected to provide a desired level of communication without unduly detrimentally compromising the strength of the delivery unit 14. The axially disposed channels 68 are of course located radially outwardly from the elongated component 23 so that the channels 68 need not extend axially therethrough.

The delivery unit 14 is rigid and preferably does not bend or deform under the expected pressures. Preferably, it is integrally molded. It is essential that the delivery unit 14 be formed from a bio-absorbable material, such as those materials well known in the implant art. For example, it is preferably made from polyglycolic acid, polylactic acid, or combinations thereof (e.g., copolymers and blends thereof).

Multiple delivery units 14 may be placed adjacent to one another in an area of removed damaged articular cartilage so that a large portion of the removed area will be filled with the arrays 12. In this case, the delivery units 14 are preferably regular polygons and fit in an adjacent and contiguous array manner. A circular delivery unit may be used when only one delivery unit is used or when only partial coverage of the removed area is desired.

The insert 16 is made essentially of porous material in the form of a matrix or sponge, preferably defining at least 95% void volume so that it can serve as a biological scaffold for infiltration of cells to regenerate the articular cartilage. Typically it has the felt-like feel of a nonwoven textile. The insert 16 may be manually bendable or movable when it is necessary to push, press or fit it into the delivery unit 14. It is essential that the insert 16 consist essentially (typically at least 99% by weight) of a bio-absorbable material selected from the group consisting of hyaluronic acid (e.g., as a fibrous matrix), polyglycolic acid (e.g., as a fibrous matrix), collagen, including type I collagen (e.g., as a sponge matrix), polylactic acid (e.g., as a fibrous matrix), fibrin island (which may be filled and cast into the delivery unit), collagen gel (which may be overcoated in a polyglycolic acid matrix), isolated periosteal cells, polydioxane, polyester, alginate, or combinations thereof. The polylactic acid, and to a lesser extent the hyaluronic acid, polyglycolic acid, and alginate, contribute to the toughness and longevity (i.e., lifespan in situ after implantation) of the insert 16. The insert may be fused (i.e., heat treated or boiled) to modify its crystallinity and therefore its hardness and durability. The isolated periosteal cells may be cultured in the insert or overlaid into the insert at the time of surgery. Other cell types, such as mesenchymal stem cells or chondrocytes, may also be added to the insert.

Additionally, in a preferred embodiment of the invention, the insert 16 may contain within the matrix "repair factors" such as growth factors and/or binding factors that are well known in the medical field. For example, the insert 16 may contain as growth factors fibroblast growth factor (acidic or basic), transforming growth factor beta (1, 2,3 or any of the members of the supergene family of TGF-beta, such as bone morphogenic protein, BMP), insulin, insulin-like growth factor 1 and 2, platelet-derived growth factor, or combinations thereof. The binding factors that may be used in the insert include fibronectin, RGD polypeptide, and combinations thereof. Typically, the repair factors total less than 1% by weight of the insert, but may range up to 10%, depending on the specific activities and release kinetics of the factors. The repair factors may be chemically combined with the basic implant composition (e.g., during its polymerization) or may be added to an already formed basic implant composition. In the former case, additional repair factor will typically become available as the basic implant composition biodegrades.

Referring now to Fig. 5, after surgical removal of the damaged or destroyed articular cartilage, the elongated component 23 (which extends downward from the concave bottom portion 30 of the support frame 22) is inserted into the cancellous bone 74 through the subchondral bone plate 72 located beneath the damaged articular cartilage area. The support frame 22 is supported by the subchondral bone plate 72. The elongated component 23 has a blunt, sloped bottom 40 so that the elongated component 23 can be easily inserted into the cancellous bone 74, which is a soft region of the bone. The bottom 40 of the elongated cylindrical component 23 is blunt so that the bottom 40 will not break when the elongated cylindrical component 23 is inserted within the cancellous bone 74. When the extended component 23 is inserted into the soft cancellous bone 74, the cancellous bone 74 is displaced by and forms around the radially extending ribs 38 of the extended component 23. In this way, the extended component 23 and thus the entire cartilage repair system 10 is held in place.

When the delivery unit 20 is placed into the bone, the upper frame 24 of the support frame 22 is planar with the undamaged articular cartilage 76. The windows 66 and the upper frame 24 of the support frame 22 are not placed within the bone, but remain exposed to the surrounding articular cartilage. The upper surface 52 of the polymeric insert 50 is exposed to the joint space environment. The upper part of the outer surface of the side walls 26 of the support frame 22 laterally borders either the upper portion of the outer surface of the side walls 26 of adjacent support frames 22 (see Fig. 6) or to undamaged articular cartilage 76 when placed adjacent to a peripheral portion of an area of removed cartilage. The bottom portion of the outer surface of the side walls 26 of the support frame 22 (ie, the portions below the windows 66) rests on and is laterally adjacent to the subchondral bone plate 72.

When the cartilage repair system of the invention is delivered to an area of removed damaged articular cartilage through the subchondral bone plate 72 into the cancellous bone 74, the channels 68 in the bottom portion 30 of the support frame 22 allow communication between the healthy cancellous bone 74 and the damaged articular cartilage area via a chondrogenic, growth-supporting matrix. This allows vascular penetration and cell migration leading to regeneration of the articular cartilage. The regenerated articular cartilage is functionally similar to undamaged articular cartilage. The cartilage repair system of the invention is bio-absorbed over time and therefore does not need to be surgically removed during or after cartilage regeneration. The absorption rate is composition dependent and can range from 6-12 weeks to one year, depending on the site-specific application.

As the basic bio-absorbable composition of the insert 16 is degraded or hydrolyzed over time, any repair factors contained therein are progressively released into the site, promoting further cellular regeneration. Cellular regeneration occurs throughout the insert.

The term "bio-absorbable" is used in the specification and claims to refer to a material that is broken down or absorbed by the body so that the regenerated articular cartilage therearound is functionally similar to undamaged articular cartilage.

To summarize, the present invention provides a system for regenerating articular cartilage, wherein the regenerated articular cartilage is functionally similar to undamaged articular cartilage and therefore replaces damaged or destroyed articular cartilage, without using cement or a non-bio-absorbable prosthetic device.

Having now shown and described in detail the preferred embodiments of the present invention, various modifications and improvements thereto will be readily apparent to those skilled in the art. Accordingly, the scope of the present invention is to be construed broadly and limited only by the appended claims and not by the foregoing description.

Claims (23)

1. A cartilage repair system adapted for attachment to a bone surface to produce a chondrogenic growth-supporting matrix comprising a delivery unit (14) consisting essentially of fully bio-absorbable material that is dimensionally stable in synovial fluid, the unit having a support frame (22) and means (23) for attaching the unit (14) to and within the bone, and a porous, ceramic-free insert (16) consisting essentially of fully bio-absorbable material and supported by the support frame (22) to provide a chondrogenic growth-supporting matrix, characterized in that the support frame (22) is provided with openings (66, 68, 42) to allow vascular penetration and cell migration to the insert. 2. The cartilage repair system of claim 1, wherein the insert (16) includes a repair factor releasably disposed in said insert to assist in providing the chrondogenic growth-supporting matrix. 3. The cartilage repair system of claim 3, wherein the support frame (22) has an open upper end (24) and a bottom (30) defining a plurality of channels (68) to allow vessel penetration and cell migration to the bottom (56) of the insert. 4. The cartilage repair system of claim 3, wherein the insert (16) has sides (54), and the support frame (22) has side walls (26) defining windows (66) through which the insert (66) extends to allow cell migration to the sides of the insert (16) through an adjacent healthy area of articular cartilage. 5. The cartilage repair system of claim 1, wherein the unit (14) and the insert (16) define an assembly (12), and the system consists of a plurality of assemblies (12) adjacent and contiguous to one another. 6. The cartilage repair system of claim 1, wherein the unit (14) is stronger than the insert (16). 7. The cartilage repair system of claim 1, additionally including means (60, 62; 64, 66) that preclude relative rotation of the unit (14) and the insert (16). 8. The cartilage repair system of claim 1, 2 or 7, wherein the porous insert (16) defines at least 95 vol.% voids for establishing communication between the remote area and the adjacent healthy area for a chondrogenic growth-supporting matrix. 9. A cartilage repair system according to claim 8 when dependent on claim 2, wherein the repair factor is a growth factor. 10. The cartilage repair system of claim 9, wherein the growth factor is selected from the group consisting of fibroblast growth factor, platelet-derived growth factor, and combinations thereof. 11. A cartilage repair system according to claim 8 when dependent on claim 2, wherein the repair factor is a binding factor. 12. The cartilage repair system of claim 11, wherein the binding factor is selected from the group consisting of fibronectin, RGD polypeptide, and combinations thereof. 13. Cartilage repair system according to claim 5, wherein the delivery units (14) of the arrangements are polygonal in their configuration and fit. 14. The cartilage repair system of claim 8, wherein the insert (16) consists essentially of a bio-absorbable material selected from the group consisting of hyaluronic acid, polyglycolic acid, collagen, polylactic acid, fibrin clot, periosteal cells, polydioxane, polyester, alginate, and combinations thereof. 15. The cartilage repair system of claim 8 or 14, wherein the delivery unit (14) comprises a bio-absorbable material selected from the group consisting of hyaluronic acid, polyglycolic acid, polylactic acid, alginate, and combinations thereof. 16. The cartilage repair system of claim 8, 9, 14 or 15, wherein the delivery unit (14) defines channels (68) to allow vessel penetration and cell migration to an adjacent surface (56) of the insert (16). 17. The cartilage repair system of claim 8, wherein the delivery unit (14) is integrally molded. 18. A cartilage repair system according to claim 16, including a plurality of arrays (12), wherein the delivery units (14) of the arrays (12) are polygonal in their configuration and fit, wherein, in use, the delivery units (14) of the arrays (12) are to be placed in the healthy bone area and the remote area, and wherein the inserts (16) of the arrays produce the chrondrogenous, growth-supporting matrix over a substantial portion of the remote area. 19. The cartilage repair system of claim 8, wherein the delivery unit (14) is configured as a polygon. 20. The cartilage repair system of claim 16, wherein the delivery unit (14) comprises a platform (22) to receive and support the insert (16) and a pin (23) to mount the platform (22) relative to the adjacent healthy area, the pin (23) including retention means. 21. A cartilage repair system according to claim 1 or claim 20, wherein the delivery unit (14) includes means for retaining itself in the bone without expansion of the dimensions thereof or relative rotation thereof. 22. The bioabsorbable cartilage repair system of claim 1, claim 20 or claim 21, wherein the bioabsorbable delivery unit (14) is configured as a polygon. 23. The cartilage repair system of claim 16, wherein the insert includes a repair factor releasably disposed in the insert to assist in producing the chondrogenic growth-supporting matrix, wherein the repair factor is selected from the group consisting of a growth factor, a binding factor, and combinations thereof.