There are various types of cartilage, e.g., hyaline cartilage and fibrocartilage. Hyaline cartilage is found at the articular surfaces of bones, e.g., in the joints, and is responsible for providing the smooth gliding motion characteristic of moveable joints. Articular cartilage is firmly attached to the underlying bones and measures typically less than 5 mm in thickness in human joints, with considerable variation depending on joint and site within the joint. In addition, articular cartilage is aneural, avascular, and alymphatic. In adult humans, this cartilage derives its nutrition by a double diffusion system through the synovial membrane and through the dense matrix of the cartilage to reach the chondrocyte, the cells that are found in the connective tissue of cartilage.
Adult cartilage has a limited ability of repair; thus, damage to cartilage produced by disease, such as rheumatoid and/or osteoarthritis, or trauma can lead to serious physical deformity and debilitation. Furthermore, as human articular cartilage ages, its tensile properties change. The superficial zone of the knee articular cartilage exhibits an increase in tensile strength up to the third decade of life, after which it decreases markedly with age as detectable damage to type II collagen occurs at the articular surface. The deep zone cartilage also exhibits a progressive decrease in tensile strength with increasing age, although collagen content does not appear to decrease. These observations indicate that there are changes in mechanical and, hence, structural organization of cartilage with aging that, if sufficiently developed, can predispose cartilage to traumatic damage.
For example, the superficial zone of the knee articular cartilage exhibits an increase in tensile strength up to the third decade of life, after which it decreases markedly with age as detectable damage to type II collagen occurs at the articular surface. The deep zone cartilage also exhibits a progressive decrease in tensile strength with increasing age, although collagen content does not appear to decrease. These observations indicate that there are changes in mechanical and, hence, structural organization of cartilage with aging that, if sufficiently developed, can predispose cartilage to traumatic damage.
Once damage occurs, joint repair can be addressed through a number of approaches. One approach includes the use of matrices, tissue scaffolds or other carriers implanted with cells (e.g., chondrocytes, chondrocyte progenitors, stromal cells, mesenchymal stem cells, etc.). These solutions have been described as a potential treatment for cartilage and meniscal repair or replacement. See, also, International Publications WO 99/51719 to Fofonoff, published Oct. 14, 1999; WO01/91672 to Simon et al., published Dec. 6, 2001; and WO01/17463 to Mannsmann, published Mar. 15, 2001; U.S. Pat. No. 6,283,980 B1 to Vibe-Hansen et al., issued Sep. 4, 2001, U.S. Pat. No. 5,842,477 to Naughton issued Dec. 1, 1998, U.S. Pat. No. 5,769,899 to Schwartz et al. issued Jun. 23, 1998, U.S. Pat. No. 4,609,551 to Caplan et al. issued Sep. 2, 1986, U.S. Pat. No. 5,041,138 to Vacanti et al. issued Aug. 29, 1991, U.S. Pat. No. 5,197,985 to Caplan et al. issued Mar. 30, 1993, U.S. Pat. No. 5,226,914 to Caplan et al. issued Jul. 13, 1993, U.S. Pat. No. 6,328,765 to Hardwick et al. issued Dec. 11, 2001, U.S. Pat. No. 6,281,195 to Rueger et al. issued Aug. 28, 2001, and U.S. Pat. No. 4,846,835 to Grande issued Jul. 11, 1989. However, clinical outcomes with biologic replacement materials such as allograft and autograft systems and tissue scaffolds have been uncertain since most of these materials cannot achieve a morphologic arrangement or structure similar to or identical to that of normal, disease-free human tissue it is intended to replace. Moreover, the mechanical durability of these biologic replacement materials remains uncertain.
Usually, severe damage or loss of cartilage is treated by replacement of the joint with a prosthetic material, for example, silicone, e.g. for cosmetic repairs, or metal alloys. See, e.g., U.S. Pat. No. 6,383,228 to Schmotzer, issued May 7, 2002; U.S. Pat. No. 6,203,576 to Afriat et al., issued Mar. 20, 2001; U.S. Pat. No. 6,126,690 to Ateshian, et al., issued Oct. 3, 2000. Implantation of these prosthetic devices is usually associated with loss of underlying tissue and bone without recovery of the full function allowed by the original cartilage and, with some devices, serious long-term complications associated with the loss of significant amount of tissue and bone can include infection, osteolysis and also loosening of the implant.
Further, joint arthroplasties are highly invasive and require surgical resection of the entire or the majority of the articular surface of one or more bones. With these procedures, the marrow space is reamed in order to fit the stem of the prosthesis. The reaming results in a loss of the patient's bone stock. U.S. Pat. No. 5,593,450 to Scott et al. issued Jan. 14, 1997 discloses an oval domed shaped patella prosthesis. The prosthesis has a femoral component that includes two condyles as articulating surfaces. The two condyles meet to form a second trochlear groove and ride on a tibial component that articulates with respect to the femoral component. A patella component is provided to engage the trochlear groove. U.S. Pat. No. 6,090,144 to Letot et al. issued Jul. 18, 2000 discloses a knee prosthesis that includes a tibial component and a meniscal component that is adapted to be engaged with the tibial component through an asymmetrical engagement.
Another joint subject to invasive joint procedures is the hip. U.S. Pat. No. 6,262,948 to Storer et al. issued Sep. 30, 2003 discloses a femoral hip prosthesis that replaces the natural femoral head. U.S. Patent Publications 2002/0143402 A1 and 2003/0120347 to Steinberg published Oct. 3, 2002 and Jun. 26, 2003, respectively, also disclose a hip prosthesis that replaces the femoral head and provides a member for communicating with the ball portion of the socket within the hip joint.
A variety of materials can be used in replacing a joint with a prosthetic, for example, silicone, e.g. for cosmetic repairs, or suitable metal alloys are appropriate. See, e.g., U.S. Pat. No. 6,443,991 B1 to Running issued Sep. 3, 2002, U.S. Pat. No. 6,387,131 B1 to Miehlke et al. issued May 14, 2002; U.S. Pat. No. 6,383,228 to Schmotzer issued May 7, 2002; U.S. Pat. No. 6,344,059 B1 to Krakovits et al. issued Feb. 5, 1002; U.S. Pat. No. 6,203,576 to Afriat et al. issued Mar. 20, 2001; U.S. Pat. No. 6,126,690 to Ateshian et al. issued Oct. 3, 2000; U.S. Pat. No. 6,013,103 to Kaufman et al. issued Jan. 11, 2000. Implantation of these prosthetic devices is usually associated with loss of underlying tissue and bone without recovery of the full function allowed by the original cartilage and, with some devices, serious long-term complications associated with the loss of significant amounts of tissue and bone can cause loosening of the implant. One such complication is osteolysis. Once the prosthesis becomes loosened from the joint, regardless of the cause, the prosthesis will then need to be replaced. Since the patient's bone stock is limited, the number of possible replacement surgeries is also limited for joint arthroplasty.
As can be appreciated, joint arthroplasties are highly invasive and require surgical resection of the entire, or a majority of the, articular surface of one or more bones involved in the repair. Typically with these procedures, the marrow space is fairly extensively reamed in order to fit the stem of the prosthesis within the bone. Reaming results in a loss of the patient's bone stock and over time subsequent osteolysis will frequently lead to loosening of the prosthesis. Further, the area where the implant and the bone mate degrades over time requiring the prosthesis to eventually be replaced. Since the patient's bone stock is limited, the number of possible replacement surgeries is also limited for joint arthroplasty. In short, over the course of 15 to 20 years, and in some cases even shorter time periods, the patient can run out of therapeutic options ultimately resulting in a painful, non-functional joint.
A variety of tools are available to assist surgeons in performing joint surgery. In the knee, for example, U.S. Pat. No. 4,501,266 to McDaniel issued Feb. 26, 1985 discloses a knee distraction device that facilitates knee arthroplasty. The device has an adjustable force calibration mechanism that enables the device to accommodate controlled selection of the ligament-tensioning force to be applied to the respective, opposing sides of the knee. U.S. Pat. No. 5,002,547 to Poggie et al. issued Mar. 26, 1991 discloses a modular apparatus for use in preparing the bone surface for implantation of a modular total knee prosthesis. The apparatus has cutting guides, templates, alignment devices along with a distractor and clamping instruments that provide modularity and facilitate bone resection and prosthesis implantation. U.S. Pat. No. 5,250,050 to Poggie et al. issued Oct. 5, 1993 is also directed to a modular apparatus for use in preparing a bone surface for the implantation of a modular total knee prosthesis. U.S. Pat. No. 5,387,216 to Thornhill et al. issued Feb. 7, 1995 discloses instrumentation for use in knee revision surgery. A bearing sleeve is provided that is inserted into the damaged canal in order to take up additional volume. The rod passes through the sleeve and is positioned to meet the natural canal of the bone. The rod is then held in a fixed position by the bearing sleeve. A cutting guide can then be mounted on the rod for cutting the bone and to provide a mounting surface for the implant. U.S. Pat. No. 6,056,756 to Eng et al. issued May 2, 2000 discloses a tool for preparing the distal femoral end for a prosthetic implant. The tool lays out the resection for prosthetic replacement and includes a jack for pivotally supporting an opposing bone such that the jack raises the opposing bone in flexion to the spacing of the intended prosthesis. U.S. Pat. No. 6,106,529 to Techiera issued Aug. 22, 2000 discloses an epicondylar axis referencing drill guide for use in resection to prepare a bone end for prosthetic joint replacement. U.S. Pat. No. 6,296,646 to Williamson issued Oct. 2, 2001 discloses a system that allows a practitioner to position the leg in the alignment that is directed at the end of the implant procedure and to cut both the femur and tibia while the leg is fixed in alignment. U.S. Pat. No. 6,620,168 to Lombardi et al. issued Sep. 16, 2003 discloses a tool for intermedullary revision surgery along with tibial components.
U.S. Pat. No. 5,578,037 to Sanders et al. issued Nov. 26, 1996 discloses a surgical guide for femoral resection. The guide enables a surgeon to resect a femoral neck during a hip arthroplasty procedure so that the femoral prosthesis can be implanted to preserve or closely approximate the anatomic center of rotation of the hip.
U.S. Pat. No. 6,206,927 to Fell, et al., issued Mar. 27, 2001, and U.S. Pat. No. 6,558,421 to Fell, et al., issued May 6, 2003, disclose a surgically implantable knee prosthesis that does not require bone resection. This prosthesis is described as substantially elliptical in shape with one or more straight edges. Accordingly, these devices are not designed to substantially conform to the actual shape (contour) of the remaining cartilage in vivo and/or the underlying bone. Thus, integration of the implant can be extremely difficult due to differences in thickness and curvature between the patient's surrounding cartilage and/or the underlying subchondral bone and the prosthesis.
Interpositional knee devices that are not attached to both the tibia and femur have been described. For example, Platt et al. (1969) “Mould Arthroplasty of the Knee,” Journal of Bone and Joint Surgery 51 B(1):76-87, describes a hemi-arthroplasty with a convex undersurface that was not rigidly attached to the tibia. Devices that are attached to the bone have also been described. Two attachment designs are commonly used. The McKeever design is a cross-bar member, shaped like a “t” from a top perspective view, that extends from the bone mating surface of the device such that the “t” portion penetrates the bone surface while the surrounding surface from which the “t” extends abuts the bone surface. See McKeever, “Tibial Plateau Prosthesis,” Chapter 7, p. 86. An alternative attachment design is the Macintosh design, which replaces the “t” shaped fin for a series of multiple flat serrations or teeth. See Potter, “Arthroplasty of the Knee with Tibial Metallic Implants of the McKeever and Macintosh Design,” Surg. Clins. Of North Am. 49(4): 903-915 (1969).
U.S. Pat. No. 4,502,161 to Wall issued Mar. 5, 1985, describes a prosthetic meniscus constructed from materials such as silicone rubber or Teflon with reinforcing materials of stainless steel or nylon strands. U.S. Pat. No. 4,085,466 to Goodfellow et al. issued Mar. 25, 1978, describes a meniscal component made from plastic materials. Reconstruction of meniscal lesions has also been attempted with carbon-fiber-polyurethane-poly (L-lactide). Leeslag, et al., Biological and Biomechanical Performance of Biomaterials (Christel et al., eds.) Elsevier Science Publishers B.V., Amsterdam. 1986. pp. 347-352. Reconstruction of meniscal lesions is also possible with bioresorbable materials and tissue scaffolds.
However, currently available devices do not always provide ideal alignment with the articular surfaces and the resultant joint congruity. Poor alignment and poor joint congruity can, for example, lead to instability of the joint. In the knee joint, instability typically manifests as a lateral instability of the joint.
Thus, there remains a need for compositions for joint repair, including methods and compositions that facilitate the integration between the cartilage replacement system and the surrounding cartilage. There is also a need for tools that increase the accuracy of cuts made to the bone in a joint in preparation for surgical implantation of, for example, an artificial joint.
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