Patent Application
20120245699
The present invention relates to orthopedic implants and systems, such as joint implants, interpositional implants, and mobile bearing implants.
A conventional prosthetic joint implant may include single or multiple components. For example, a joint implant often referred to as a mobile bearing implant may include a bearing component that is interposed between first and second components. The bearing component extends the range of movements that can be accommodated, such as sliding and rotational movement.
Implantation of these prosthetic devices is usually associated with loss of underlying tissue and bone 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. Such joint arthroplasties can be 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.
Another concern with prosthetic joint implants, such as a mobile bearing implant, is to ensure full range of appropriate motion. This must be balanced with the risk of dislocation of the device.
In accordance with a first embodiment of the invention, a mobile bearing implant includes a first component. The first component includes a bone facing surface for engaging one of a substantially uncut articular cartilage surface and a substantially uncut subchondral bone surface. The bone facing surface substantially matches the one of the articular cartilage surface and the subchondral bone surface. The mobile bearing implant further includes an external surface. A bearing component has a first surface for slidingly engaging the external surface of the first component, and a second surface for engaging at least one of a second component, bone, and cartilage.
In accordance with related embodiments of the invention, the bone facing surface of the first component may substantially match one of a substantially uncut articular cartilage surface of a tibia and a substantially uncut subchondral bone surface of a tibia, and the second surface of the bearing component engages a femoral implant component.
In further related embodiments of the invention, the external surface of the first component may be curved. The external surface may include a plurality of curved surfaces with varying radii. The external surface may be flat along at least one axis.
In yet further related embodiments of the invention, the external surface of the first component may include a slot, and the first surface of the bearing component includes an anchor. The anchor slidingly engages the slot so as to direct movement of the bearing component along the external surface of the first component. The slot may be curved. The slot may include a plurality of curvatures with varying radii. The slot may be sloped.
In still a further embodiment of the invention, the first component may include at least one stop for limiting motion of the bearing component, the stop including a curved surface for contacting the bearing component.
In accordance with another embodiment of the invention, a mobile bearing implant includes: a first component having a bone facing surface for engaging at least one of bone and cartilage; and an external surface. A bearing component has a first surface for slidingly engaging the external surface of the first component, and a second surface for engaging at least one of a second component, bone, and cartilage. The external surface includes at least one of a concavity and a convexity.
In accordance with related embodiments of the invention, the bone facing surface of the first component may engage a tibial articular surface, and the second surface of the bearing component engages a femoral implant component. The external surface of the first component may include a plurality of curved surfaces with varying radii. The external surface may be flat along at least one axis.
In accordance with further related embodiments of the invention, the external surface of the first component may includes a slot, and the first surface of the bearing component includes an anchor. The anchor slidingly engages the slot so as to direct movement of the bearing component along the external surface of the first component. The slot may be curved, or sloped. The slot may include a plurality of curvatures with varying radii.
In accordance with still further related embodiments of the invention, the first component may include at least one stop for limiting motion of the bearing component, the stop including a curved surface for contacting the bearing component.
In accordance with another embodiment of the invention, a mobile bearing implant includes a first component including: a bone facing surface for engaging one of bone and cartilage; and an external surface. The external surface includes a slot. A bearing component has a first surface for slidingly engaging the external surface of the first component, and a second surface for engaging at least one of a second component, bone, and cartilage. The first surface of the bearing component includes an anchor. The anchor slidingly engages the slot so as to direct movement of the bearing component along the external surface of the first component.
In accordance with related embodiments of the invention, the bone facing surface of the first component may engage a tibial articular surface, and the second surface of the bearing component engages a femoral implant component. The slot may be curved. The slot may include a plurality of curvatures with varying radii. The slot may be sloped.
In accordance with another embodiment of the invention, a mobile bearing implant includes: a first component having a bone facing surface for engaging one of bone and cartilage; and an external surface. A bearing component has a first surface and a second surface, the first surface for slidingly engaging the external surface of the first component, and the second surface for engaging at least one of a second component, bone, and cartilage. At least one of the first surface and the second surface includes a curved surface in one dimension, the curved surface having a plurality of radii.
In accordance with another embodiment of the invention, a mobile bearing implant includes: a first component having a bone facing surface for engaging one of bone and cartilage; and an external surface. A bearing component has a first surface and a second surface, the first surface for slidingly engaging the external surface of the first component, and the second surface for engaging at least one of a second component, bone, and cartilage. The first component has an outer perimeter of varying radii.
In accordance with related embodiments of the invention, the outer perimeter of the first component may be kidney shaped. The outer perimeter of the first component may be asymmetric. The first component may have a larger, or smaller, outer perimeter than the bearing component.
In accordance with embodiments related to the above-described embodiments, the first component may be fixedly anchored into an articular surface using one or more fins, keels, and/or pegs. The fins, keels and/or pegs may have various orientations and lengths. For example, the fins and/or pegs may be perpendicular to each other. The bone facing surface of the first component may sit on top of the natural surface of the subchondral bone or articular cartilage, with only the anchoring mechanism protruding into the bone.
In accordance with further embodiments related to the above-described embodiments, the first component may include one or more stops, that restrict motion of one or more components of the mobile bearing. The stop(s) may restrict motion in one or more dimensions. The stop(s) may be oriented in various directions. Each stop may include curved and/or straight portions For example, a stop may have a constant or variable radius.
The joint implants described herein may be implemented for the knee, hip, ankle, shoulder, elbow, wrist, and hand. The various joint implants described herein may be used, without limitation, in conjunction with knee implants, including a unicompartmental arthroplasty, medial or lateral; a bicompartmental arthroplasty that covers portions or all of one femoral condyle, medial or lateral, and the trochlea, and a total knee arthroplasty system. In a total knee arthroplasty system, the intercondylar region can be preserved by using a medial and a lateral tibial device in combination. Both devices may be a fixed, non-mobile bearing, both can be a mobile bearing, or one can be a fixed, non-mobile bearing, while the other is a mobile bearing.
The foregoing features of the invention will be more readily understood by reference to the following detailed description, taken with reference to the accompanying drawings, in which:
The following description is presented to enable any person skilled in the art to make and use the invention. Various modifications to the embodiments described will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments and applications without departing from the spirit and scope of the present invention as defined by the appended claims. Thus, the present invention is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein. To the extent necessary to achieve a complete understanding of the invention disclosed, the specification and drawings of all issued patents, patent publications, and patent applications cited in this application are incorporated herein by reference.
As will be appreciated by those of skill in the art, methods recited herein may be carried out in any order of the recited events which is logically possible, as well as the recited order of events. Furthermore, where a range of values is provided, it is understood that every intervening value, between the upper and lower limit of that range and any other stated or intervening value in that stated range is encompassed within the invention. Also, it is contemplated that any optional feature of the inventive variations described may be set forth and claimed independently, or in combination with any one or more of the features described herein.
The practice of the present invention can employ, unless otherwise indicated, conventional and digital methods of x-ray imaging and processing, x-ray tomosynthesis, ultrasound including A-scan, B-scan and C-scan, computed tomography (CT scan), magnetic resonance imaging (MRI), optical coherence tomography, single photon emission tomography (SPECT) and positron emission tomography (PET) within the skill of the art. Such techniques are explained fully in the literature and need not be described herein. See, e.g., X-Ray Structure Determination: A Practical Guide, 2nd Edition, editors Stout and Jensen, 1989, John Wiley & Sons, publisher; Body CT: A Practical Approach, editor Slone, 1999, McGraw-Hill publisher; X-ray Diagnosis: A Physician's Approach, editor Lam, 1998 Springer-Verlag, publisher; and Dental Radiology: Understanding the X-Ray Image, editor Laetitia Brocklebank 1997, Oxford University Press publisher. See also, The Essential Physics of Medical Imaging (2nd Ed.), Jerrold T. Bushberg, et al.
The present invention provides methods and compositions for repairing joints, particularly for repairing articular cartilage and for facilitating the integration of a wide variety of cartilage repair materials into a subject. Among other things, the techniques described herein allow for the customization of cartilage repair material to suit a particular subject, for example in terms of size, cartilage thickness and/or curvature. When the shape (e.g., size, thickness and/or curvature) of the articular cartilage surface is an exact or near anatomic fit with the non-damaged cartilage or with the subject's original cartilage, the success of repair is enhanced. The repair material can be shaped prior to implantation and such shaping can be based, for example, on electronic images that provide information regarding curvature or thickness of any “normal” cartilage surrounding the defect and/or on curvature of the bone underlying the defect. Thus, the current invention provides, among other things, for minimally invasive methods for partial joint replacement. The methods will require only minimal or, in some instances, no loss in bone stock. Additionally, unlike with current techniques, the methods described herein will help to restore the integrity of the articular surface by achieving an exact or near anatomic match between the implant and the surrounding or adjacent cartilage and/or subchondral bone.
Advantages of the present invention can include, but are not limited to, (i) customization of joint repair, thereby enhancing the efficacy and comfort level for the patient following the repair procedure; (ii) eliminating the need for a surgeon to measure the defect to be repaired intraoperatively in some embodiments; (iii) eliminating the need for a surgeon to shape the material during the implantation procedure; (iv) providing methods of evaluating curvature of the repair material based on bone or tissue images or based on intraoperative probing techniques; (v) providing methods of repairing joints with only minimal or, in some instances, no loss in bone stock; (vi) improving postoperative joint congruity; (vii) improving the postoperative patient recovery in some embodiments and (viii) improving postoperative function, such as range of motion.
Thus, the methods described herein allow for the design and use of joint repair material that more precisely fits the defect (e.g., site of implantation) or the articular surface(s) and, accordingly, provides improved repair of the joint,
The methods and compositions described herein can be used to treat defects resulting from disease of the cartilage (e.g., osteoarthritis), bone damage, cartilage damage, trauma, and/or degeneration due to overuse or age. The invention allows, among other things, a health practitioner to evaluate and treat such defects. The size, volume and shape of the area of interest can include only the region of cartilage that has the defect, but preferably will also include contiguous parts of the cartilage surrounding the cartilage defect.
As will be appreciated by those of skill in the art, size, curvature and/or thickness measurements can be obtained using any suitable technique. For example, one-dimensional, two-dimensional, and/or three-dimensional measurements can be obtained using suitable mechanical means, laser devices, electromagnetic or optical tracking systems, molds, materials applied to the articular surface that harden and “memorize the surface contour,” and/or one or more imaging techniques known in the art. Measurements can be obtained non-invasively and/or intraoperatively (e.g., using a probe or other surgical device). As will be appreciated by those of skill in the art, the thickness of the repair device can vary at any given point depending upon patient's anatomy and/or the depth of the damage to the cartilage and/or bone to be corrected at any particular location on an articular surface.
As will be appreciated by those of skill in the art, the practitioner can proceed directly from the step of generating a model representation of the target joint 30 to the step of selecting a suitable joint replacement implant 50 as shown by the arrow 32. Additionally, following selection of suitable joint replacement implant 50, the steps of obtaining measurement of target joint 10, generating model representation of target joint 30 and generating projected model 40, can be repeated in series or parallel as shown by the flow 24, 25, 26.
As will be appreciated by those of skill in the art, the practitioner can proceed directly from the step of generating a model representation of the target joint 30 to the step of designing a suitable joint replacement implant 52 as shown by the arrow 38. Similar to the flow shown above, following the design of a suitable joint replacement implant 52, the steps of obtaining measurement of target joint 10, generating model representation of target joint 30 and generating projected model 40, can be repeated in series or parallel as shown by the flow 42, 43, 44.
Once the surfaces have been measured, the user either selects the best fitting implant contained in a library of implants 130 or generates a patient-specific implant 132. These steps can be repeated as desired or necessary to achieve the best fitting implant for a patient, 131, 133. As will be appreciated by those of skill in the art, the process of selecting or designing an implant can be tested against the information contained in the MRI or x-ray of the patient to ensure that the surfaces of the device achieves a good fit relative to the patient's joint surface. Testing can be accomplished by, for example, superimposing the implant image over the image for the patient's joint. Once it has been determined that a suitable implant has been selected or designed, the implant site can be prepared 140, for example by removing cartilage or bone from the joint surface, or the implant can be placed into the joint 150.
The joint implant selected or designed achieves anatomic or near anatomic fit with the existing surface of the joint while presenting a mating surface for the opposing joint surface that replicates the natural joint anatomy. In this instance, both the existing surface of the joint can be assessed as well as the desired resulting surface of the joint. This technique is particularly useful for implants that are not anchored into the bone.
As will be appreciated by those of skill in the art, the physician, or other person practicing the invention, can obtain a measurement of a target joint 10 and then either design 52 or select 50 a suitable joint replacement implant.
A wide variety of materials find use in the practice of the present invention, including, but not limited to, plastics, metals, crystal free metals, ceramics, biological materials (e.g., collagen or other extracellular matrix materials), hydroxyapatite, cells (e.g., stem cells, chondrocyte cells or the like), or combinations thereof. Based on the information (e.g., measurements) obtained regarding the defect and the articular surface and/or the subchondral bone, a repair material can be formed or selected. Further, using one or more of these techniques described herein, a cartilage replacement or regenerating material having a curvature that will fit into a particular cartilage defect, will follow the contour and shape of the articular surface, and will match the thickness of the surrounding cartilage. The repair material can include any combination of materials, and typically includes at least one non-pliable material, for example materials that are not easily bent or changed.
Currently, joint repair systems often employ metal and/or polymeric materials including, for example, prostheses which are anchored into the underlying bone (e.g., a femur in the case of a knee prosthesis). See, e.g., U.S. Pat. No. 6,203,576 to Afriat, et al. issued Mar. 20, 2001 and U.S. Pat. No. 6,322,588 to Ogle, et al. issued Nov. 27, 2001, and references cited therein. A wide-variety of metals are useful in the practice of the present invention, and can be selected based on any criteria. For example, material selection can be based on resiliency to impart a desired degree of rigidity. Non-limiting examples of suitable metals include silver, gold, platinum, palladium, iridium, copper, tin, lead, antimony, bismuth, zinc, titanium, cobalt, stainless steel, nickel, iron alloys, cobalt alloys, such as Elgiloy®, a cobalt-chromium-nickel alloy, and MP35N, a nickel-cobalt-chromium-molybdenum alloy, and Nitinol™, a nickel-titanium alloy, aluminum, manganese, iron, tantalum, crystal free metals, such as Liquidmetal® alloys (available from LiquidMetal Technologies, www.liquidmetal.com), other metals that can slowly form polyvalent metal ions, for example to inhibit calcification of implanted substrates in contact with a patient's bodily fluids or tissues, and combinations thereof.
Suitable synthetic polymers include, without limitation, polyamides (e.g., nylon), polyesters, polystyrenes, polyacrylates, vinyl polymers (e.g., polyethylene, polytetrafluoroethylene, polypropylene and polyvinyl chloride), polycarbonates, polyurethanes, poly dimethyl siloxanes, cellulose acetates, polymethyl methacrylates, polyether ether ketones, ethylene vinyl acetates, polysulfones, nitrocelluloses, similar copolymers and mixtures thereof. Bioresorbable synthetic polymers can also be used such as dextran, hydroxyethyl starch, derivatives of gelatin, polyvinylpyrrolidone, polyvinyl alcohol, poly[N-(2-hydroxypropyl)methacrylamide], poly(hydroxy acids), poly(epsilon-caprolactone), polylactic acid, polyglycolic acid, poly(dimethyl glycolic acid), poly(hydroxy butyrate), and similar copolymers can also be used.
Other materials would also be appropriate, for example, the polyketone known as polyetheretherketone (PEEK™). This includes the material PEEK 450G, which is an unfilled PEEK approved for medical implantation available from Victrex of Lancashire, Great Britain. (Victrex is located at www.matweb.com or see Boedeker www.boedeker.com). Other sources of this material include Gharda located in Panoli, India (www.ghardapolymers.com).
It should be noted that the material selected can also be filled. For example, other grades of PEEK are also available and contemplated, such as 30% glass-filled or 30% carbon filled, provided such materials are cleared for use in implantable devices by the FDA, or other regulatory body. Glass filled PEEK reduces the expansion rate and increases the flexural modulus of PEEK relative to that portion which is unfilled. The resulting product is known to be ideal for improved strength, stiffness, or stability. Carbon filled PEEK is known to enhance the compressive strength and stiffness of PEEK and lower its expansion rate. Carbon filled PEEK offers wear resistance and load carrying capability.
As will be appreciated, other suitable similarly biocompatible thermoplastic or thermoplastic polycondensate materials that resist fatigue, have good memory, are flexible, and/or deflectable have very low moisture absorption, and good wear and/or abrasion resistance, can be used without departing from the scope of the invention. The implant can also be comprised of polyetherketoneketone (PEKK).
Other materials that can be used include polyetherketone (PEK), polyetherketoneetherketoneketone (PEKEKK), and polyetheretherketoneketone (PEEKK), and generally a polyaryletheretherketone. Further other polyketones can be used as well as other thermoplastics.
Reference to appropriate polymers that can be used for the implant can be made to the following documents, all of which are incorporated herein by reference. These documents include: PCT Publication WO 02/02158 A1, dated Jan. 10, 2002 and entitled Bio-Compatible Polymeric Materials; PCT Publication WO 02/00275 A1, dated Jan. 3, 2002 and entitled Bio-Compatible Polymeric Materials; and PCT Publication WO 02/00270 A1, dated Jan. 3, 2002 and entitled Bio-Compatible Polymeric Materials.
The polymers can be prepared by any of a variety of approaches including conventional polymer processing methods. Preferred approaches include, for example, injection molding, which is suitable for the production of polymer components with significant structural features, and rapid prototyping approaches, such as reaction injection molding and stereo-lithography. The substrate can be textured or made porous by either physical abrasion or chemical alteration to facilitate incorporation of the metal coating. Other processes are also appropriate, such as extrusion, injection, compression molding and/or machining techniques. Typically, the polymer is chosen for its physical and mechanical properties and is suitable for carrying and spreading the physical load between the joint surfaces.
More than one metal and/or polymer can be used in combination with each other. For example, one or more metal-containing substrates can be coated with polymers in one or more regions or, alternatively, one or more polymer-containing substrate can be coated in one or more regions with one or more metals.
The system or prosthesis can be porous or porous coated. The porous surface components can be made of various materials including metals, ceramics, and polymers. These surface components can, in turn, be secured by various means to a multitude of structural cores formed of various metals. Suitable porous coatings include, but are not limited to, metal, ceramic, polymeric (e.g., biologically neutral elastomers such as silicone rubber, polyethylene terephthalate and/or combinations thereof) or combinations thereof. See, e.g., U.S. Pat. No. 3,605,123 to Hahn, issued Sep. 20, 1971. U.S. Pat. No. 3,808,606 to Tronzo issued May 7, 1974 and U.S. Pat. No. 3,843,975 to Tronzo issued Oct. 29, 1974; U.S. Pat. No. 3,314,420 to Smith issued Apr. 18, 1967; U.S. Pat. No. 3,987,499 to Scharbach issued Oct. 26, 1976; and German Offenlegungsschrift 2,306,552. There can be more than one coating layer and the layers can have the same or different porosities. See, e.g., U.S. Pat. No. 3,938,198 to Kahn, et al., issued Feb. 17, 1976.
The coating can be applied by surrounding a core with powdered polymer and heating until cured to form a coating with an internal network of interconnected pores. The tortuosity of the pores (e.g., a measure of length to diameter of the paths through the pores) can be important in evaluating the probable success of such a coating in use on a prosthetic device. See, also, U.S. Pat. No. 4,213,816 to Morris issued Jul. 22, 1980. The porous coating can be applied in the form of a powder and the article as a whole subjected to an elevated temperature that bonds the powder to the substrate. Selection of suitable polymers and/or powder coatings can be determined in view of the teachings and references cited herein, for example based on the melt index of each.
Repair materials can also include one or more biological material either alone or in combination with non-biological materials. For example, any base material can be designed or shaped and suitable cartilage replacement or regenerating material(s) such as fetal cartilage cells can be applied to be the base. The cells can be then be grown in conjunction with the base until the thickness (and/or curvature) of the cartilage surrounding the cartilage defect has been reached. Conditions for growing cells (e.g., chondrocytes) on various substrates in culture, ex vivo and in vivo are described, for example, in U.S. Pat. Nos. 5,478,739 to Slivka et al. issued Dec. 26, 1995; 5,842,477 to Naughton et al. issued Dec. 1, 1998; 6,283,980 to Vibe-Hansen et al., issued Sep. 4, 2001, and 6,365,405 to Salzmann et al. issued Apr. 2, 2002. Non-limiting examples of suitable substrates include plastic, tissue scaffold, a bone replacement material (e.g., a hydroxyapatite, a bioresorbable material), or any other material suitable for growing a cartilage replacement or regenerating material on it.
Biological polymers can be naturally occurring or produced in vitro by fermentation and the like. Suitable biological polymers include, without limitation, collagen, elastin, silk, keratin, gelatin, polyamino acids, cat gut sutures, polysaccharides (e.g., cellulose and starch) and mixtures thereof. Biological polymers can be bioresorbable.
Biological materials used in the methods described herein can be autografts (from the same subject); allografts (from another individual of the same species) and/or xenografts (from another species). See, also, International Patent Publications WO 02/22014 to Alexander et al. published Mar. 21, 2002 and WO 97/27885 to Lee published Aug. 7, 1997. In certain embodiments autologous materials are preferred, as they can carry a reduced risk of immunological complications to the host, including re-absorption of the materials, inflammation and/or scarring of the tissues surrounding the implant site.
In one embodiment of the invention, a probe is used to harvest tissue from a donor site and to prepare a recipient site. The donor site can be located in a xenograft, an allograft or an autograft. The probe is used to achieve a good anatomic match between the donor tissue sample and the recipient site. The probe is specifically designed to achieve a seamless or near seamless match between the donor tissue sample and the recipient site. The probe can, for example, be cylindrical. The distal end of the probe is typically sharp in order to facilitate tissue penetration. Additionally, the distal end of the probe is typically hollow in order to accept the tissue. The probe can have an edge at a defined distance from its distal end, e.g. at 1 cm distance from the distal end and the edge can be used to achieve a defined depth of tissue penetration for harvesting. The edge can be external or can be inside the hollow portion of the probe. For example, an orthopedic surgeon can take the probe and advance it with physical pressure into the cartilage, the subchondral bone and the underlying marrow in the case of a joint such as a knee joint. The surgeon can advance the probe until the external or internal edge reaches the cartilage surface. At that point, the edge will prevent further tissue penetration thereby achieving a constant and reproducible tissue penetration. The distal end of the probe can include one or more blades, saw-like structures, or tissue cutting mechanism. For example, the distal end of the probe can include an iris-like mechanism consisting of several small blades. The blade or blades can be moved using a manual, motorized or electrical mechanism thereby cutting through the tissue and separating the tissue sample from the underlying tissue. Typically, this will be repeated in the donor and the recipient. In the case of an iris-shaped blade mechanism, the individual blades can be moved so as to close the iris thereby separating the tissue sample from the donor site.
In another embodiment of the invention, a laser device or a radio frequency device can be integrated inside the distal end of the probe. The laser device or the radio frequency device can be used to cut through the tissue and to separate the tissue sample from the underlying tissue.
In one embodiment of the invention, the same probe can be used in the donor and in the recipient. In another embodiment, similarly shaped probes of slightly different physical dimensions can be used. For example, the probe used in the recipient can be slightly smaller than that used in the donor thereby achieving a tight fit between the tissue sample or tissue transplant and the recipient site. The probe used in the recipient can also be slightly shorter than that used in the donor thereby correcting for any tissue lost during the separation or cutting of the tissue sample from the underlying tissue in the donor material.
Any biological repair material can be sterilized to inactivate biological contaminants such as bacteria, viruses, yeasts, molds, mycoplasmas and parasites. Sterilization can be performed using any suitable technique, for example radiation, such as gamma radiation.
Any of the biological materials described herein can be harvested with use of a robotic device. The robotic device can use information from an electronic image for tissue harvesting.
In certain embodiments, the cartilage replacement material has a particular biochemical composition. For instance, the biochemical composition of the cartilage surrounding a defect can be assessed by taking tissue samples and chemical analysis or by imaging techniques. For example, WO 02/22014 to Alexander describes the use of gadolinium for imaging of articular cartilage to monitor glycosaminoglycan content within the cartilage. The cartilage replacement or regenerating material can then be made or cultured in a manner, to achieve a biochemical composition similar to that of the cartilage surrounding the implantation site. The culture conditions used to achieve the desired biochemical compositions can include, for example, varying concentrations. Biochemical composition of the cartilage replacement or regenerating material can, for example, be influenced by controlling concentrations and exposure times of certain nutrients and growth factors.
Using information on thickness and curvature of the cartilage and/or subchondral bone, a physical model of the surfaces of the articular cartilage and/or of the underlying bone can be created. This physical model can be representative of a limited area within the joint or it can encompass the entire joint. This model can also take into consideration the presence or absence of a meniscus as well as the presence or absence of some or all of the cartilage. For example, in the knee joint, the physical model can encompass only the medial or lateral femoral condyle, both femoral condyles and the notch region, the medial tibial plateau, the lateral tibia! plateau, the entire tibia! plateau, the medial patella, the lateral patella, the entire patella or the entire joint. The location of a diseased area of cartilage can be determined, for example using a 3D coordinate system or a 3D Euclidian distance as described in WO 02/22014.
In this way, the size of the defect to be repaired can be determined. This process takes into account that, for example, roughly 80% of patients have a healthy lateral component. As will be apparent, some, but not all, defects will include less than the entire cartilage. Thus, in one embodiment of the invention, the thickness of the normal or only mildly diseased cartilage surrounding one or more cartilage defects is measured. This thickness measurement can be obtained at a single point or, preferably, at multiple points, for example 2 point, 4-6 points, 7-10 points, more than 10 points or over the length of the entire remaining cartilage. Furthermore, once the size of the defect is determined, an appropriate therapy (e.g., articular repair system) can be selected such that as much as possible of the healthy, surrounding tissue is preserved.
In other embodiments, the curvature of the articular surface can be measured to design and/or shape the repair material. Further, both the thickness of the remaining cartilage and the curvature of the articular surface can be measured to design and/or shape the repair material. Alternatively, the curvature of the subchondral bone can be measured and the resultant measurement(s) can be used to either select or shape a cartilage replacement material. For example, the contour of the subchondral bone can be used to re-create a virtual cartilage surface: the margins of an area of diseased cartilage can be identified. The subchondral bone shape in the diseased areas can be measured. A virtual contour can then be created by copying the subchondral bone surface into the cartilage surface, whereby the copy of the subchondral bone surface connects the margins of the area of diseased cartilage. In shaping the device, the contours can be configured to mate with existing cartilage or to account for the removal of some or all of the cartilage.
The implant 200 has an upper surface 202, a lower surface 204 and a peripheral edge 206. The upper surface 202 is formed so that it forms a mating surface for receiving the opposing joint surface; in this instance partially concave to receive the femur. The concave surface can be variably concave such that it presents a surface to the opposing joint surface, e.g. a negative surface of the mating surface of the femur it communicates with. As will be appreciated by those of skill in the art, the negative impression, need not be a perfect one.
The upper surface 202 of the implant 200 can be shaped by any of a variety of means. For example, the upper surface 202 can be shaped by projecting the surface from the existing cartilage and/or bone surfaces on the tibial plateau, or it can be shaped to mirror the femoral condyle in order to optimize the complimentary surface of the implant when it engages the femoral condyle. Alternatively, the superior surface 202 can be configured to mate with an inferior surface of an implant configured for the opposing femoral condyle.
The lower surface 204 has a convex surface that matches, or nearly matches, the tibial plateau of the joint such that it creates an anatomic or near anatomic fit with the tibial plateau. Depending on the shape of the tibial plateau, the lower surface can be partially convex as well. Thus, the lower surface 204 presents a surface to the tibial plateau that fits within the existing surface. It can be formed to match the existing surface or to match the surface after articular resurfacing.
As will be appreciated by those of skill in the art, the convex surface of the lower surface 204 need not be perfectly convex. Rather, the lower surface 204 is more likely consist of convex and concave portions that fit within the existing surface of the tibial plateau or the re-surfaced plateau. Thus, the surface is essentially variably convex and concave.
Turning now to
Additionally, as shown in
In an alternate embodiment shown in
As shown in
FIG. 2S(1-9) illustrate an alternate embodiment of implant 200. As illustrated in
Turning now to FIG. 2S(4) a tangent of the implant is deselected, leaving three posterior curves. FIG. 2S(5) shows the result of tangent propagation. FIG. 2S(6) illustrates the effect on the design when the bottom curve is selected without tangent propagation. The result of tangent propagation and selection is shown in FIG. 2S(7). As can be seen in FIG. 2S(8-9) the resulting corner has a softer edge but sacrifices less than 0.5 mm of joint space. As will be appreciated by those of skill in the art, additional cutting planes can be added without departing from the scope of the invention.
Turning now to
The anchors 306 could take on a variety of other forms without departing from the scope of the invention while still accomplishing the same objective of providing increased stability of the implant 300 in the joint. These forms include, but are not limited to, pins, bulbs, balls, teeth, etc. Additionally, one or more joint anchors 306 can be provided as desired. As illustrated in
Turning now to
As will be appreciated by those of skill in the art, the implant 400 can be manufactured from a material that has memory such that the implant can be configured to snap-fit over the condyle. Alternatively, it can be shaped such that it conforms to the surface without the need of a snap-fit.
Similar to the implant of
¥Body Weight (BW) taken as a 60 year old male, with 173 cm height for an average body weight of 74 kg (163 lbs).
1“Tibial Plateau Surface Stress in TKA: A Factor Influencing Polymer Failure Series III - Posterior Stabilized Designs;” Paul D. Postak, B.Sc, Christine S. Heim, B.Sc, A. Seth Greenwald, D. Phil.; Orthopaedic Research Laboratories, The Mt. Sinai Medical Center, Cleveland, Ohio. Presented at the 62nd Annual AAOS Meeting, 1995.
Using the implant 500 described in this application, the three point loading will occur from set-up 1 (2900 N). To replicate a worst case loading scenario, a 75/25 load distribution (75% of 2900 N=2175 N) will be used. The loading will be concentrated on a 6 mm diameter circular area located directly below and normal to the ped on the bearing surface.
Turning to the cantilever loading shown in
Turning now to
In another embodiment of the invention, the implant 500 can have a superior surface 502 which substantially conforms to the surface of the condyle but which has at one flat portion corresponding to an oblique cut on the bone as shown in
Turning now to
By dividing the surfaces of the medial and lateral compartments into independent articulating surfaces, as shown in
Turning now to
The arthroplasty system can be designed to reflect aspects of the tibial shape, femoral shape and/or patellar shape. Tibial shape and femoral shape can include cartilage, bone or both. Moreover, the shape of the implant can also include portions or all components of other articular structures such as the menisci. The menisci are compressible, in particular during gait or loading. For this reason, the implant can be designed to incorporate aspects of the meniscal shape accounting for compression of the menisci during loading or physical activities. For example, the undersurface 204 of the implant 200 can be designed to match the shape of the tibial plateau including cartilage or bone or both. The superior surface 202 of the implant 200 can be a composite of the articular surface of the tibia (in particular in areas that are not covered by menisci) and the meniscus. Thus, the outer aspects of the device can be a reflection of meniscal height. Accounting for compression, this can be, for example, 20%, 40%, 60% or 80% of uncompressed meniscal height.
Similarly the superior surface 304 of the implant 300 can be designed to match the shape of the femoral condyle including cartilage or bone or both. The inferior surface 302 of the implant 300 can be a composite of the surface of the tibial plateau (in particular in areas that are not covered by menisci) and the meniscus. Thus, at least a portion of the outer aspects of the device can be a reflection of meniscal height. Accounting for compression, this can be, for example, 20%, 40%, 60% or 80% of uncompressed meniscal height. These same properties can be applied to the implants shown in
In some embodiments, the outer aspect of the device reflecting the meniscal shape can be made of another, preferably compressible material. If a compressible material is selected it is preferably designed to substantially match the compressibility and biomechanical behavior of the meniscus. The entire device can be made of such a material or non-metallic materials in general.
The height and shape of the menisci for any joint surface to be repaired can be measured directly on an imaging test. If portions, or all, of the meniscus are torn, the meniscal height and shape can be derived from measurements of a contralateral joint or using measurements of other articular structures that can provide an estimate on meniscal dimensions.
In another embodiment, the superior face of the implants 300, 400 or 500 can be shaped according to the femur. The shape can preferably be derived from the movement patterns of the femur relative to the tibial plateau thereby accounting for variations in femoral shape and tibiofemoral contact area as the femoral condyle ilexes, extends, rotates, translates and glides on the tibia and menisci.
The movement patterns can be measured using any current or future test know in the art such as fluoroscopy, MRI, gait analysis and combinations thereof.
In various embodiments, a joint implant may include two or more components that are slideably engageable forming a mobile bearing. The mobile bearing can help provide more unconstrained or more physiologic motion in the joint, for example, knee motion of the femur relative to the tibia.
The bone facing surface 1104 may be a mirror image of, and engage, a substantially uncut articular cartilage surface and/or a substantially uncut subchondral bone surface. The bone-facing surface may be formed using, without limitation, the above-described imaging and modeling techniques. The bone facing surface 1104 may match and conform with the existing underlying surface to achieve an anatomic or near anatomic fit, such that it replicates the natural joint anatomy. Such a non-invasive approach advantageously does not require surgical resection of the articular bone surface.
In various embodiments, the joint implant 1100 may be configured to be used, without limitation, in a hip, knee, ankle, should, elbow, wrist, or hand. For example, the joint implant 1100 maybe directed at a knee, with the bone facing surface 1104 of the first component 1102 engaging a tibial articular surface, and the second surface 1107 of the bearing component 1101 articulating with a femoral component 1103.
The bearing surface between the bearing component 1101 and the first component 1102 may be, without limitation, flat, as shown in
Alternatively, the joint component 1200 may be anchored via one or more pegs 1210 into, without limitation, the tibial plateau, as shown in
Any anchoring mechanism known in the art may be used.
The bone-facing surface of the first component 1202 of the joint implant 1200 may sit on top of, and conform with, the subchondral bone and/or articular cartilage without cutting the tibia, with only the anchoring mechanism protruding into the bone. Alternatively, the surgeon may cut the articular surface (e.g., the tibial plateau in a knee implant), and the implant can be seated on top of the cut. Standard techniques for cutting the articular surface known in the art may be used. Note that in various embodiments, the bone-facing surface may conform with the subchondral bone and/or articular cartilage such that the first component is sufficiently self-centering, with requiring any anchoring mechanism or cuts.
In various embodiments, the bearing surface between the bearing component 1301 and the first component 1302 may be flat and the second surface 1307 of the bearing component 1301 (e.g., facing the femoral component in a knee implant) may also be flat, as shown in
In another embodiment, the bearing component 1301 of the joint implant 1300 may be smaller in one or more dimensions than the first component 1302, as shown in
In further embodiments, the recessed slot 1704 may have a changing slope, further guiding the motion of the bearing component 1701.
The stop 1910 may be curved with variable radius and it can contain straight portions (
The various joint implants described herein may be used, without limitation, in conjunction with knee implants, including a unicompartmental arthroplasty, medial or lateral; a bicompartmental arthroplasty that covers portions or all of one femoral condyle, medial or lateral, and the trochlea, and a total knee arthroplasty system. In a total knee arthroplasty system, the intercondylar region can be preserved by using a medial and a lateral tibial device in combination. Both devices may be a fixed, non-mobile bearing, both can be a mobile bearing, or one can be a fixed, non-mobile bearing, while the other is a mobile bearing. As described above, the joint implants described herein may also be implemented for the hip, ankle, shoulder, elbow, wrist, and hand.
In various embodiments, the joint implant may have one or more mobile bearings.
The various components used for the mobile bearing joint implant may be composed of metal, plastic, ceramic or any other material know in the art. Different components may be composed of different materials, e.g. one metal and one plastic. Alternatively, only the same material may be used for the bearing surfaces, e.g. ceramic. The bearing surfaces of each component may vary in material composition e.g. ceramic on the side facing the femoral condyle and metal on the undersurface.
As described herein, repair systems of various sizes, curvatures and thicknesses can be obtained. These repair systems can be catalogued and stored to create a library of systems from which an appropriate system for an individual patient can then be selected. In other words, a defect, or an articular surface, is assessed in a particular subject and a pre-existing repair system having a suitable shape and size is selected from the library for further manipulation (e.g., shaping) and implantation.
In certain instances shaping of the repair material will be required before or after formation (e.g., growth to desired thickness), for example where the thickness of the required cartilage material is not uniform (e.g., where different sections of the cartilage replacement or regenerating material require different thicknesses).
The replacement material can be shaped by any suitable technique including, but not limited to, casting techniques, mechanical abrasion, laser abrasion or ablation, radiofrequency treatment, cryoablation, variations in exposure time and concentration of nutrients, enzymes or growth factors and any other means suitable for influencing or changing cartilage thickness. See, e.g., WO 00/15153 to Mansmann published Mar. 23, 2000; If enzymatic digestion is used, certain sections of the cartilage replacement or regenerating material can be exposed to higher doses of the enzyme or can be exposed longer as a means of achieving different thicknesses and curvatures of the cartilage replacement or regenerating material in different sections of said material.
The material can be shaped manually and/or automatically, for example using a device into which a pre-selected thickness and/or curvature has been input and then programming the device using the input information to achieve the desired shape.
In addition to, or instead of, shaping the cartilage repair material, the site of implantation (e.g., bone surface, any cartilage material remaining, etc.) can also be shaped by any suitable technique in order to enhance integration of the repair material.
The articular repair system can be formed or selected so that it will achieve a near anatomic fit or match with the surrounding or adjacent cartilage, subchondral bone, menisci and/or other tissue. The shape of the repair system can be based on the analysis of an electronic image (e.g. MRI, CT, digital tomosynthesis, optical coherence tomography or the like). If the articular repair system is intended to replace an area of diseased cartilage or lost cartilage, the near anatomic fit can be achieved using a method that provides a virtual reconstruction of the shape of healthy cartilage in an electronic image.
In one embodiment of the invention, a near normal cartilage surface at the position of the cartilage defect can be reconstructed by interpolating the healthy cartilage surface across the cartilage defect or area of diseased cartilage. This can, for example, be achieved by describing the healthy cartilage by means of a parametric surface (e.g. a B-spline surface), for which the control points are placed such that the parametric surface follows the contour of the healthy cartilage and bridges the cartilage defect or area of diseased cartilage. The continuity properties of the parametric surface will provide a smooth integration of the part that bridges the cartilage defect or area of diseased cartilage with the contour of the surrounding healthy cartilage. The part of the parametric surface over the area of the cartilage defect or area of diseased cartilage can be used to determine the shape or part of the shape of the articular repair system to match with the surrounding cartilage.
In another embodiment, a near normal cartilage surface at the position of the cartilage defect or area of diseased cartilage can be reconstructed using morphological image processing. In a first step, the cartilage can be extracted from the electronic image using manual, semi-automated and/or automated segmentation techniques (e.g., manual tracing, region growing, live wire, model-based segmentation), resulting in a binary image. Defects in the cartilage appear as indentations that can be filled with a morphological closing operation performed in 2-D or 3-D with an appropriately selected structuring element. The closing operation is typically defined as a dilation followed by an erosion. A dilation operator sets the current pixel in the output image to 1 if at least one pixel of the structuring element lies inside a region in the source image. An erosion operator sets the current pixel in the output image to 1 if the whole structuring element lies inside a region in the source image. The filling of the cartilage defect or area of diseased cartilage creates a new surface over the area of the cartilage defect or area of diseased cartilage that can be used to determine the shape or part of the shape of the articular repair system to match with the surrounding cartilage or subchondral bone.
As described above, the articular repair system can be formed or selected from a library or database of systems of various sizes, curvatures and thicknesses so that it will achieve a near anatomic fit or match with the surrounding or adjacent cartilage and/or subchondral bone. These systems can be pre-made or made to order for an individual patient. In order to control the fit or match of the articular repair system with the surrounding or adjacent cartilage or subchondral bone or menisci and other tissues preoperatively, a software program can be used that projects the articular repair system over the anatomic position where it will be implanted. Suitable software is commercially available and/or readily modified or designed by a skilled programmer.
In yet another embodiment, the articular surface repair system can be projected over the implantation site using one or more 3-D images. The cartilage and/or subchondral bone and other anatomic structures are extracted from a 3-D electronic image such as an MRI or a CT using manual, semi-automated and/or automated segmentation techniques. A 3-D representation of the cartilage and/or subchondral bone and other anatomic structures as well as the articular repair system is generated, for example using a polygon or NURBS surface or other parametric surface representation. For a description of various parametric surface representations see, for example Foley, J. D. et al., Computer Graphics: Principles and Practice in C; Addison-Wesley, 2nd edition, 1995).
The 3-D representations of the cartilage and/or subchondral bone and other anatomic structures and the articular repair system can be merged into a common coordinate system. The articular repair system can then be placed at the desired implantation site. The representations of the cartilage, subchondral bone, menisci and other anatomic structures and the articular repair system are rendered into a 3-D image, for example application programming interfaces (APIs) OpenGL® (standard library of advanced 3-D graphics functions developed by SGI, Inc.; available as part of the drivers for PC-based video cards, for example from www.nvidia.com for NVIDIA video cards or www.3dlabs.com for 3Dlabs products, or as part of the system software for Unix workstations) or DirectX® (multimedia API for Microsoft Windows® based PC systems; available from www.microsoft.com). The 3-D image can be rendered showing the cartilage, subchondral bone, menisci or other anatomic objects, and the articular repair system from varying angles, e.g. by rotating or moving them interactively or non-interactively, in real-time or non-real-time.
The software can be designed so that the articular repair system, including surgical tools and instruments with the best fit relative to the cartilage and/or subchondral bone is automatically selected, for example using some of the techniques described above. Alternatively, the operator can select an articular repair system, including surgical tools and instruments and project it or drag it onto the implantation site using suitable tools and techniques. The operator can move and rotate the articular repair systems in three dimensions relative to the implantation site and can perform a visual inspection of the fit between the articular repair system and the implantation site. The visual inspection can be computer assisted. The procedure can be repeated until a satisfactory fit has been achieved. The procedure can be performed manually by the operator; or it can be computer-assisted in whole or part. For example, the software can select a first trial implant that the operator can test. The operator can evaluate the fit. The software can be designed and used to highlight areas of poor alignment between the implant and the surrounding cartilage or subchondral bone or menisci or other tissues. Based on this information, the software or the operator can then select another implant and test its alignment. One of skill in the art will readily be able to select, modify and/or create suitable computer programs for the purposes described herein.
In another embodiment, the implantation site can be visualized using one or more cross-sectional 2-D images. Typically, a series of 2-D cross-sectional images will be used. The 2-D images can be generated with imaging tests such as CT, MRI, digital tomosynthesis, ultrasound, or optical coherence tomography using methods and tools known to those of skill in the art. The articular repair system can then be superimposed onto one or more of these 2-D images. The 2-D cross-sectional images can be reconstructed in other planes, e.g. from sagittal to coronal, etc. Isotropic data sets (e.g., data sets where the slice thickness is the same or nearly the same as the in-plane resolution) or near isotropic data sets can also be used. Multiple planes can be displayed simultaneously, for example using a split screen display. The operator can also scroll through the 2-D images in any desired orientation in real time or near real time; the operator can rotate the imaged tissue volume while doing this. The articular repair system can be displayed in cross-section utilizing different display planes, e.g. sagittal, coronal or axial, typically matching those of the 2-D images demonstrating the cartilage, subchondral bone, menisci or other tissue. Alternatively, a three-dimensional display can be used for the articular repair system. The 2-D electronic image and the 2-D or 3-D representation of the articular repair system can be merged into a common coordinate system. The articular repair system can then be placed at the desired implantation site. The series of 2-D cross-sections of the anatomic structures, the implantation site and the articular repair system can be displayed interactively (e.g. the operator can scroll through a series of slices) or non-interactively (e.g. as an animation that moves through the series of slices), in real-time or non-real-time.
Rapid prototyping is a technique for fabricating a three-dimensional object from a computer model of the object. A special printer is used to fabricate the prototype from a plurality of two-dimensional layers. Computer software sections the representations of the object into a plurality of distinct two-dimensional layers and then a three-dimensional printer fabricates a layer of material for each layer sectioned by the software. Together the various fabricated layers form the desired prototype. More information about rapid prototyping techniques is available in US Patent Publication No 2002/0079601A1 to Russell et al., published Jun. 27, 2002. An advantage to using rapid prototyping is that it enables the use of free form fabrication techniques that use toxic or potent compounds safely. These compounds can be safely incorporated in an excipient envelope, which reduces worker exposure
A powder piston and build bed are provided. Powder includes any material (metal, plastic, etc.) that can be made into a powder or bonded with a liquid. The power is rolled from a feeder source with a spreader onto a surface of a bed. The thickness of the layer is controlled by the computer. The print head then deposits a binder fluid onto the powder layer at a location where it is desired that the powder bind. Powder is again rolled into the build bed and the process is repeated, with the binding fluid deposition being controlled at each layer to correspond to the three-dimensional location of the device formation. For a further discussion of this process see, for example, US Patent Publication No 2003/017365A1 to Monkhouse et al. published Sep. 18, 2003.
The rapid prototyping can use the two dimensional images obtained, as described above in Section I, to determine each of the two-dimensional shapes for each of the layers of the prototyping machine. In this scenario, each two dimensional image slice would correspond to a two dimensional prototype slide. Alternatively, the three-dimensional shape of the defect can be determined, as described above, and then broken down into two dimensional slices for the rapid prototyping process. The advantage of using the three-dimensional model is that the two-dimensional slices used for the rapid prototyping machine can be along the same plane as the two-dimensional images taken or along a different plane altogether.
Rapid prototyping can be combined or used in conjunction with casting techniques. For example, a shell or container with inner dimensions corresponding to an articular repair system can be made using rapid prototyping. Plastic or wax-like materials are typically used for this purpose. The inside of the container can subsequently be coated, for example with a ceramic, for subsequent casting. Using this process, personalized casts can be generated.
Rapid prototyping can be used for producing articular repair systems. Rapid prototyping can be performed at a manufacturing facility. Alternatively, it may be performed in the operating room after an intraoperative measurement has been performed.
Prior to performing surgery on a patient, the surgeon can preoperatively make a determination of the alignment of the knee using, for example, an erect AP x-ray. In performing preoperative assessment any lateral and patella spurs that are present can be identified.
Using standard surgical techniques, the patient is anesthetized and an incision is made in order to provide access to the portion or portions of the knee joint to be repaired. A medial portal can be used initially to enable arthroscopy of the joint. Thereafter, the medial portal can be incorporated into the operative incision and/or standard lateral portals can be used.
Once an appropriate incision has been made, the exposed compartment is inspected for integrity, including the integrity of the ligament structures. If necessary, portions of the meniscus can be removed as well as any spurs or osteophytes that were identified in the AP x-ray or that may be present within the joint. In order to facilitate removal of osteophytes, the surgeon may flex the knee to gain exposure to additional medial and medial-posterior osteophytes. Additionally, osteophytes can be removed from the patella during this process. If necessary, the medial and/or lateral meniscus can also be removed at this point, if desired, along with the rim of the meniscus.
As would be appreciated by those of skill in the art. evaluation of the medial cruciate ligament may be required to facilitate tibial osteophyte removal.
Once the joint surfaces have been prepared, the desired implants can be inserted into the joint.
To insert the device 200 of
To insert the device of
Once any implant shown in
As will be appreciated by those of skill in the art, additional treatment of the surface of the tibial plateau may be desirable depending on the configuration of the implant 200. For example, one or more channels or grooves may be formed on the surface of the tibial plateau to accommodate anchoring mechanisms such as the keel 212 shown in
To insert the device 300 shown in
It may be required to excise excess deep synovium to improve access to the joint. Additionally, all or part of the fat pad may also be excused and to enable inspection of the opposite joint compartment.
Typically, osteophytes are removed from the entire medial and/or lateral edge of the femur and the tibia as well as any osteophytes on the edge of the patella that might be significant.
Although it is possible, typically the devices 300 do not require resection of the distal femur prior to implanting the device. However, if desired, bone cuts can be performed to provide a surface for the implant.
At this juncture, the patient's leg is placed in 90° flexion position. I guide can then be placed on the condyle which covers the distal femoral cartilage. The guide enables the surgeon to determine placement of apertures that enable the implant 300 to be accurately placed on the condyle. With the guide in place, holes are drilled into the condyle to create apertures from 1-3 mm in depth. Once the apertures have been created, the guide is removed and the implant 300 is installed on the surface of the condyle. Cement can be used to facilitate adherence of the implant 300 to the condyle.
Where more than one condyle is to be repaired, e.g., using two implants 300 of
To insert the device shown in
One or more of the implants described above can be combined together in a kit such that the surgeon can select one or more implants to be used during surgery.
The foregoing description of embodiments of the present invention has been provided for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed. Many modifications and variations will be apparent to the practitioner skilled in the art. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to understand the invention and the various embodiments and with various modifications that are suited to the particular use contemplated.
This application is a continuation of U.S. patent application Ser. No. 11/537,318, entitled “Joint Arthroplasty Devices,” filed Sep. 29, 2006, which in turn claims the benefit of U.S. provisional application 60/722,171, entitled “Patient Selectable Knee Joint Arthroplasty Devices,” filed Sep. 30, 2005. U.S. patent application Ser. No. 11/537,318 also is a continuation-in-part of U.S. patent application Ser. No. 10/997,407, entitled “Patient Selectable Knee Joint Arthroplasty Devices,” filed Nov. 24, 2004, which in turn is a continuation-in-part of U.S. patent application Ser. No. 10/752,438, entitled “Patient Selectable Knee Joint Arthroplasty Devices.” filed Jan. 5, 2004, which in turn is a continuation-in-part of U.S. patent application Ser. No. 10/724,010, entitled “Patient Selectable Joint Arthroplasty Devices and Surgical Tools Facilitating Increased Accuracy, Speed and Simplicity in Performing Total and Partial Joint Arthroplasty,” filed Nov. 25, 2003, which in turn is a continuation-in-part of U.S. patent application Ser. No. 10/305,652 entitled “Methods and Compositions for Articular Repair,” filed Nov. 27, 2002, which in turn is a continuation-in-part of U.S. patent application Ser. No. 10/160,667, entitled “Methods and Compositions for Articular Resurfacing,” filed May 28, 2002, which in turn claims the benefit of U.S. provisional patent application 60/293,488 entitled “Methods To Improve Cartilage Repair Systems,” filed May 25, 2001, U.S. provisional patent application 60/363,527, entitled “Novel Devices For Cartilage Repair,” filed Mar. 12, 2002, U.S. patent application 60/380,695, entitled “Methods And Compositions for Cartilage Repair,” filed May 14, 2002 and U.S. patent application 60/380,692, entitled “Methods for Joint Repair,” filed May 14, 2002. U.S. patent application Ser. No. 10/997,407 is also a continuation-in-part of U.S. application Ser. No. 10/681,750, filed Oct. 7, 2003, entitled “Minimally Invasive Joint Implant with 3-Dimensional Geometry Matching the Articular Surfaces,” which in turn claims the benefit of U.S. provisional patent application 60/467,686 filed May 2, 2003 entitled “Joint Implants” and U.S. provisional patent application 60/416,601, entitled “Minimally Invasive Joint Implant with 3-Dimensional Geometry Matching the Articular Surfaces,” filed on Oct. 7, 2002. U.S. patent application Ser. No. 11/537,318 is also a continuation-in-part of U.S. application Ser. No. 10/681,749, filed Oct. 7, 2003, entitled “Minimally Invasive Joint Implant with 3-Dimensional Geometry Matching the Articular Surfaces,” Each of the above-described applications is incorporated herein, in their entireties, by reference.
| Number | Date | Country | |
|---|---|---|---|
| 60416601 | Oct 2002 | US | |
| 60467686 | May 2003 | US | |
| 60293488 | May 2001 | US | |
| 60363527 | Mar 2002 | US | |
| 60380692 | May 2002 | US | |
| 60380695 | May 2002 | US | |
| 60722171 | Sep 2005 | US |
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