Abstract: A system and method for aligning a patient's leg, for establishing the ultimate alignment of the leg prior to making a horizontal femoral cut or a horizontal tibial cut, for preparing the distal femur for receiving a femoral implant, and for making the horizontal, femoral and tibial cuts. The system and method incorporate a spacer, a cutting guide, and a template. The spacer is insertable between a distal femur and a proximal tibia to rotate the tibia with respect to the femur into the desired alignment. The cutting guide is engageable with the spacer, and can be fixed to the proximal tibia and the distal femur. The cutting guide has openings sized and shaped to guide a surgical saw to make the horizontal femoral cut and the horizontal tibial cut. The template is shaped to closely conform with the distal femur to allow the leg to be extended and to allow the procedure to be performed without dislocating a patella.

Abstract: A tibial implant is provided having a stem, a tray, a bushing for joining the stem and the tray, and a locking member. In use, the stem of the implant is inserted into the medullary canal of a natural tibia and the tray rests on a resected surface at the proximal end of the tibia. The tray includes a central position and an engagement portion on a lower surface thereof. The bushing includes a proximal axis of alignment in alignment with the central position of the tray and a distal axis of alignment that is co-linear to the longitudinal axis of the stem. The engagement portion of the tray is comprised of a dovetailed ring member. The bushing also includes, on a proximal end thereof, an engagement surface having first and second pairs of surfaces for, respectively, passage through the opening of the ring member and sliding complementary engagement with the dovetailed ring member.

Abstract: An implantable knee prosthesis for unicompartmental implantation into a knee joint includes a body having a substantially elliptical shape in plan and a pair of opposed faces. A peripheral face extends between the opposed faces and has first and second opposed sides and first and second opposed ends. At least one aperture extends through the body and extends from a first one of the faces to a second one of the faces.

Abstract: A prosthetic medical device exhibiting improved wear resistance is fabricated by irradiating at least one polyolefinic material in the presence of an inert atmosphere to yield a cross-linked irradiated polyolefinic material; blending at least one non-irradiated polyolefinic material with the at least one irradiated polyolefinic material, and forming the prosthetic medical device from the blended material. Selectively cross-linked polymeric compositions may be created by blending a specific amount of cross-linked resins with a specific amount of uncross-linked resins then cured into a polymeric matrix whereby the desired degree or percentage of overall cross-linking is obtained. The polymeric material may then be formed directly into a finished article by injection molding the polymeric material.

Abstract: The invention relates to a knee joint prosthesis having a bearing and a biologic ligament for replacing the articulating knee portion of a femur and a tibia. The knee joint prosthesis includes a femoral component, a tibial component, a bearing member, and a biologic ligament. The femoral component includes a first femoral bearing surface and a second femoral bearing surface. The tibial component includes a tibial bearing surface. The bearing member includes a first bearing surface which is operable to articulate with the first femoral bearing surface, a second bearing surface which is operable to articulate with the second femoral bearing surface and a third bearing surface which is operable to articulate with the tibial bearing surface. The biologic ligament is coupled to both the tibia and the femur to prevent the knee joint from dislocating and guiding the femoral component along a desired path during extension and flexion.

Abstract: An artificial joint (1) suitable for use as an endoprosthesis for a human knee joint, having a first joint compartment (2) formed by a first condyle (3) and a first socket (4) and a second joint compartment (5) formed by a second condyle (6) and a second socket (7). The contact surfaces (C) of the respective joint compartments (2, 5) are offset in the main functional plane. To further improve the characteristics of the artificial joint (1), the contact surfaces (C) of the two joint compartments (2, 5) are sloped as a function of the flexion angle such that the surface normals (8, 9) of the contact surfaces (C) have a common point of intersection at every flexion angle. This arrangement of the contact surfaces (C) achieves self-stabilization of the joint (1) both when a rotary motion or torsion and when lateral forces are introduced.

Abstract: The invention concerns a prosthesis wherein the contact surfaces of the femoral part (i), the insert (3) and the knee joint are defined by the combination of two curves, a spiral-type curve in the saggital plane following an undulating curve (sinusoidal) in the frontal plane. The latter comprises two concave lateral parts and a central dome-shaped convex part, the three parts being connected without any angulation, protuberance, or flat parts or bends and providing continuous medio-lateral contact on the three zones, from complete extension to complete bending, and a concave-convex nesting in the central zone.

Abstract: A tibial prosthesis has a metal tray component (1) comprising a transverse member (3) with a peripheral upstanding rim (6) and a projecting stem (4). The upstanding rim (6) includes a posterior rim portion with an undercut lip forming a pair of recesses (7, 8) and an anterior rim portion with an open angled posterior surface portion (9) and a posteriorly projecting barbed portion (10). The prosthesis also includes a tibia insert (2) made of a plastics material which fits on the tibial implant (1) within the upstanding rim (6) and has on a posterior portion thereof a shaped contour (14, 15) adapted in use to fit snugly under the undercut lip and on an anterior portion thereof an anterior surface (13) having a taper angle substantially corresponding to the angle of the open angled posterior surface portion.

Abstract: A knee prosthesis comprises a femoral component, a tibial component and a bearing component therebetween. The femoral component defines medial and lateral condylar surfaces which are in the form of respective parts of a common helix, and the bearing component has respective surfaces matching the condylar surfaces. Accordingly a patella groove in the femoral component is laterally displaced, and on flexion of the knee, in use, from an extended position there is a lateral translatory movement of the femur. Congruent contact between the femoral component and the bearing component is maintained through at least 60° of flexion of the knee from an extended position.

Abstract: A prosthesis is provided for implantation into a knee joint compartment between a femoral condyle and its corresponding tibial plateau which is suitable for patients having large tibial defects. The prosthesis includes a hard body free of any means of fixation within the knee joint compartment. The body has a generally elliptical shape in plan and a pair of opposed surfaces including a substantially flat bottom surface and an opposed top surface.

Abstract: An implantable knee prosthesis for in-vivo measuring force components along three different axes, the X-axis, the Y-axis, and the Z-axis. The prosthesis can measure six different force components along these axes while the prosthesis is under load.

Abstract: A medical implant made of polymeric material having an increased oxidation resistance is formed by a method including the steps of placing a resin powder in a sealed container. A substantial portion of the oxygen is removed from the sealed contained by either a vacuum, an oxygen absorbent or by flushing with inert gas. The container is then repressurized with a gas such as nitrogen, argon, helium or neon so that long term storage may be possible. On use, the resin in transferred to a forming device which both melts and forms the resin in an oxygen reduced atmosphere to produce a polymeric raw material such as a rod or bar stock. The medical implant is then formed from this raw material annealed and sealed in an airtight package in an oxygen reduced atmosphere. The implant is then radiation sterilized and thereafter annealed in the package for a predetermined time and temperature sufficient to form cross-links between any free radicals in neighboring polymeric chains.

Abstract: A polymeric implantable orthopaedic device that includes a first layer and a second layer where the first layer has a porosity that is different from the second layer is described. An associated method of producing a polymeric implantable orthopaedic device that includes a first layer and a second layer where the first layer has a porosity that is different from the second layer is also described.

Abstract: The present invention discloses methods for enhancing the wear-resistance of polymers, the resulting polymers, and in vivo implants made from such polymers. One aspect of this invention presents a method whereby a polymer is irradiated, preferably with gamma radiation, then thermally treated, such as by remelting of annealing. The resulting polymeric composition preferably has its most oxidized surface layer removed. Another aspect of the invention presents a general method for optimizing the wear resistance and desirable physical and/or chemical properties of a polymer by crosslinking and thermally treating it. The resulting polymeric compositions is wear-resistant and may be fabricated into an in vivo implant.

Abstract: A knee joint prosthesis, comprising at least one femoral component and at least one tibial component. The femoral component having a first portion adapted for fixable attachment to a distal end of a femur and a second portion formed with a bearing surface. The femoral component is sized so as to permit attachment to the femur of a patient without severing at least one the cruciate ligaments. The tibial component has a first surface that is adapted to cooperate with a patient's tibia, while a second surface of the tibial component is adapted to cooperate with the femoral component. The tibial component is sized so as to permit attachment to the patient's tibia without severing at least one of the cruciate ligaments.

Abstract: Disclosed is a device and method of bicompartmental arthroplasty of the knee. The device permits arthroplasty of the medial or lateral and patellofemoral compartments of the knee while leaving the opposite compartments and the anterior and posterior cruciate ligaments intact. The device provides a femoral prosthesis component that includes a trochlear surface and a tibial prosthesis component which can be secured to the tibia. The femoral component is essentially “u” shaped having an anterior leg upon which the trochlear surface is positioned and a posterior leg which engages the posterior surface of the distal end of the femur. The femoral component also has a convex articulating surface which engages a concave articulating surface of the tibial prosthesis component to approximate the articulation of a healthy knee.

Abstract: Instrumentation and a method for resurfacing a joint capsule having cartilage and meniscal surfaces such as a knee joint includes resecting a central portion of the joint cartilage on one joint member such as the tibia while leaving a meniscal rim attached to the peripheral joint capsule. A cavity is then formed in the bone underlying the central portion of the joint surface such as the lateral tibial surface. A resurfacing implant is then coupled, by cementing for example, to the cavity. A soft prosthetic meniscal implant is then coupled to the remaining meniscal ring such as by suturing.

Abstract: An improved method of performing surgery on a joint in a patient's body, such as a knee, includes making an incision in a knee portion of one leg while a lower portion of the one leg is extending downward from an upper portion of the one leg and while a foot connected with the lower portion of the one leg is below a support surface on which the patient is disposed. The incision is relatively short, for example, between seven and thirteen centimeters. A patella may be offset from its normal position with an inner side of the patella facing inward during cutting of a bone with a cutting tool. During cutting of the bone, one or more guide members having opposite ends which are spaced apart by a distance less than the width of an implant may be utilized to guide movement of a cutting tool.

Abstract: A femoral component for a prosthetic knee implant system. The femoral component comprises medial and lateral condyles, wherein the height of the medial condyle is greater than the height of the lateral condyle.

Abstract: The present invention relates to methods for determining meniscal size and shape for use in designing therapies for the treatment of various joint diseases. The invention uses an image of a joint that is processed for analysis. Analysis can include, for example, generating a thickness map, a cartilage curve, or a point cloud. This information is used to determine the extent of the cartilage defect or damage and to design an appropriate therapy, including, for example, an implant. Adjustments to the designed therapy are made to account for the materials used.

Abstract: An implant for installation into a portion of an articular surface includes a protrusion configured to cover an un-excised portion of articular surface proximate to the implant. Another implant may form a cavity to allow the un-excised portion of articular surface to remodel over a perimeter edge of the implant. The implant may also include indentations such as grooves to promote articular cartilage remodeling over a portion of the load bearing surface of the implant. An elongated or non-round implant is also provided having two opposing concentric arcuate shaped sides, as well as a method to seat such an implant in an articular surface. A method for seating an implant without cutting articular cartilage is also provided.

Abstract: This invention is directed to orthopedic implants and systems. The invention also relates to methods of implant design, manufacture, modeling and implantation as well as to surgical tools and kits used therewith. The implants are designed by analyzing the articular surface to be corrected and creating a device with an anatomic or near anatomic fit; or selecting a pre-designed implant having characteristics that give the implant the best fit to the existing defect.

Abstract: A prosthetic implant kit for implantation in a bone joint between first and second bones, such as the knee joint between a femur and a tibia, such joint having bone tunnels formed in each of the first and second bones, and the implant assembly being intended to be introduced into the bone tunnels and to be fixated therein, and implant kit assembly comprising:

Abstract: A modular knee prosthetic system used to replace the natural knee and including two distal posterior femoral components and one patellar-femoral joint component. The components have a smooth outer condylar surface and an inner bone-engaging surface and are connectable to form either an unicompartmental or bicompartmental femoral knee prosthesis.

Abstract: A tibial resurfacing system is provided that includes a drill guide, bone chisel and implant. In one aspect, the system includes a drill guide that includes a targeting ring that is shaped to be placed on the superior tibial surface and a bore section that is connected to the ring to create an axis through the tibia to the superior tibial surface in the vicinity of the targeting ring. The drill guide permits a drill pin and/or drill to be advanced through the tibia to the superior tibial surface. In another aspect, a bone chisel is provided that includes an elongated tubular structure having a first end and a bone-cutting end, and the bone-cutting end is terminated in a transverse angle thereby creating an elliptical bone-cutting face. In another aspect, an implant is provided that includes an angled bearing element formed of a cylindrical member having a first end and a second end.

Abstract: A knee prosthesis system includes a single-piece tibia plateau with two sliding cavities, a single-piece femur component with two condylar sliding surfaces, the distances between and shapes of which are adapted to the tibial sliding cavities and a pair of unconnected femoral condylar cups, the shapes of the sliding surfaces of which are adapted to the tibial sliding cavities. To be able also to adapt their relative positions, including their distances apart, to the sliding cavities, the system includes a position instrument which ensures this adapted relative position of the codylar cups.

Abstract: IM revision tools include reamers with depth markings or stops, an impactor-extractor with a coupling for attaching to tools which are inserted into and removed from the IM canal, a resection guide tower to which a cutting block is attached and which includes a notch which serves as both a witness mark and a holder for a femoral collar, a reversible clean-up cutting block with a quick-connect clamp attachable to the guide tower for resecting the distal femur, a selection of spacer blocks for measuring the space between the femur to determine the size of the components to be installed, a multiple cut cutting guide for preparing the femur, a set of 5 and 10 mm trial wedges, a trial stem valgus adapter, femoral sizing indicators which include indications of anterior/posterior offset, a stabilizer box cutting template which is attachable to the multiple cut cutting guide, and anterior/posterior offset adapters for attaching the femoral component to the IM stem.

Abstract: An instrumented joint trial has a polymer layer defining a curved contoured articulating surface. A curved contoured sensor array is positioned below the polymer layer. Other components of the joint trial, such as a body with a proximal curved contoured surface, are positioned below the sensor array. The device can be made by forming a sheet of the polymer over the curved contoured surface of the joint trial body and then adhering the sensor array to one curved contoured surface of the formed polymer. The sensor array conforms to the shape of the formed polymer layer. The system includes a mating joint trial. The device may be used by temporarily attaching the joint trial to a resected portion of bone and then articulating the joint with the instrumented trial in place.

Abstract: An improved method of performing surgery on a joint in a patient's body, such as a knee, includes making an incision in a knee portion of one leg while a lower portion of the one leg is extending downward from an upper portion of the one leg and while a foot connected with the lower portion of the one leg is below a support surface on which the patient is disposed. The incision is relatively short, for example, between seven and thirteen centimeters. A patella may be offset from its normal position with an inner side of the patella facing inward during cutting of a bone with a cutting tool. During cutting of the bone, one or more guide members having opposite ends which are spaced apart by a distance less than the width of an implant may be utilized to guide movement of a cutting tool.

Abstract: The invention relates to a knee joint endoprosthesis system. Said system comprises a femur component, two sliding bearings and a tibia component. The tibia component comprises two joint surface units and a transversal support. The transversal support is implanted into the tibia at a certain distance from an upper resection surface of the tibia and the joint surface units are supported by support elements on the transversal support and are fixed thereto.

Abstract: A cartilage plug, which is made from a biocompatible, artificial material, that is used to fill a void in natural cartilage that has been resected due to traumatic injury or chronic disease. Alternatively, the plug may be relied upon to anchor a flowable polymer to subchondral bone. The plug is prefabricatable in any size, shape, and contour and may be utilized either singly or in a plurality to fill any size void for any application. The plug may be formed of a laminated structure to match the physiological requirements of the repair site. A plurality of anchoring elements may share a single upper layer.

Abstract: An implantable knee prosthesis for in-vivo measuring force components along three different axes, the X-axis, the Y-axis, and the Z-axis. The prosthesis can measure six different force components along these axes while the prosthesis is under load.

Abstract: A system and method for prosthesis fitting in joints comprising an artificial condyle and a spacer which cooperates with the condyle to form an artificial joint. The spacer embedded with at least one sensor which is responsive to a force generated between the condyle and the spacer. The artificial joint is adapted to move between a flexed position and an extended position defining a range of motion. The sensor is responsive to the force and generates an output representative of that force. The output is transmitted, either wirelessly or other, to a processor which utilizes an analysis program to display a representation of the forces applied. A practitioner utilizing the displayed analysis may intraoperatively determine the adjustments and balancing required within the artificial joint.

Abstract: An implant for installation into a portion of an articular surface includes a protrusion configured to cover an un-excised portion of articular surface proximate to the implant. Another implant may form a cavity to allow the un-excised portion of articular surface to remodel over a perimeter edge of the implant. The implant may also include indentations such as grooves to promote articular cartilage remodeling over a portion of the load bearing surface of the implant. An elongated or non-round implant is also provided having two opposing concentric arcuate shaped sides, as well as a method to seat such an implant in an articular surface. A method for seating an implant without cutting articular cartilage is also provided.

Abstract: A femoral knee prosthesis system for resurfacing a resected articular surface at the distal end of a femur includes a femoral component adapted to mate with the resected articular surface; and an attachment member. The interior surface of the femoral component is configured to connect to the first attachment member when the femoral component is mated on the resected articular surface of the femur and when the first attachment member is passed through the medial side or the lateral side of the resected articular surface. The femoral component is available in one-piece and two-piece systems. Mating femoral components (e.g., tapered or with lips that interlock with grooves) are also disclosed.

Abstract: An implant for installation into a portion of an articular surface includes an implant shell component having a proximal load bearing wall with an outer proximal load bearing surface. A peripheral rim extending distally relative to the load bearing wall may provide a bone-facing distal pocket on the shell component. An inner implant component may be received in the bone-facing distal pocket of the implant such that a proximal surface of the inner component is spaced apart from a distal surface of the load bearing wall. The contour of the load bearing surface may be based on an original surface contour of an articular surface, and the load bearing wall of the shell component may be a deflectable wall, so that the load bearing surface can deflect under an-applied load. The space between the load bearing wall and the inner implant may include a compressible fluid such as elastomeric gels.

Abstract: Orthopedic implants which includes the components of zirconium or zirconium-based alloys having surfaces coated with oxidized zirconium or alternatively, other orthopedic implants comprising abrasion resistant surfaces contacting surfaces of cross-linked polyethylene are disclosed. Such implants provide low friction, highly wear resistant coatings especially useful in artificial joints, such as hip joints, knee joints, elbows, etc., but also useful in other implant devices as well.

Abstract: A process for forming an orthopaedic implant prosthesis bearing (10) includes the step of quenching a residual free radical population present in an irradiated polyethylene preform or bearing with a supercritical fluid.

Abstract: An artificial knee joint including a femoral component to be attached to a femur and a tibial component to be attached to a tibia, wherein in the femur component a medial condyle thereof is thicker than a lateral condyle thereof; in the tibial component, a medial articular surface thereof, which supports the medial condyle, is thinner than a lateral articular surface thereof, which supports the lateral condyle; and a joint line joining lowest points of contact surfaces between the medial and lateral condyles and the medial and lateral articular surfaces in a longitudinal cross section in a medial-lateral direction is inclined inward at virtually the same angle over the entire region of an angle of flexion-extension.

Abstract: The invention relates to a knee joint prosthesis system adapted to replace the articulating knee portion of a femur and a tibia. The knee joint prosthesis system includes a first femoral component and a second femoral component. The first femoral component includes a first femoral engagement region and a first condylar portion having a first femoral bearing surface. The first femoral engagement region is operable to engage a resecting engagement surface of the femur and the first condylar portion includes a first posterior region having a first thickness. The second femoral component includes a second femoral engagement region and a second condylar portion having a second femoral bearing surface. The second femoral engagement region is operable to engage the resected engagement surface of the femur and the second condylar portion includes a second posterior region having a second thickness.

Abstract: A patellar alignment device for determining the position of a patella prosthesis. The device comprises two components—a baseplate and a mobile component which is preferably magnetically attached to the baseplate. During a surgical procedure to replace the knee, the baseplate is temporarily attached to the back of the patella. The baseplate may contain spikes or prongs to secure it to the patella. The baseplate further includes a series of slots for marking the patella. The mobile component resembles a patella and is placed on the baseplate. The patella with the alignment device in place is then placed in position on the knee and trialed. Because the mobile component is free to move on the baseplate, it finds the position that is most amenable to a natural knee movement. The alignment device is then exposed and the patella is marked at the position of the mobile component. Since the baseplate contains a series of slots, the patella can be easily marked at several locations around the mobile component.

Abstract: An insertion instrument for a pair of sliding prostheses, said instrument having, on a supporting plate (2), two clamps which are each intended to receive a sliding prosthesis and whose spacing is adjustable. The clamping jaws (10, 11) of the clamps have projections (18) which interact with the side edges of the sliding prostheses to provide positioning. Two vertically adjustable slide-surface supports (6) are provided. According to the invention, in order to adjust the spacing between the clamps on the supporting plate (2), a slide guide with adjustment spindle (22) is provided, and the slide-surface supports (6) are arranged in a fixed position on the supporting plate (2). They have a width which is large enough to support the sliding prostheses in any chosen spacing.

Abstract: A self-centering meniscal prosthesis device suitable for minimally invasive, surgical implantation into the cavity between a femoral condyle and the corresponding tibial plateau is composed of a hard, high modulus material shaped such that the contour of the device and the natural articulation of the knee exerts a restoring force on the free-floating device.

Abstract: A distal femoral knee-replacement component provides additional points of cam action to facilitate a more normal rollback while inhibiting initial translation which could lead to increased wear and sub-optimal patella femoral mechanics. The inventive component preferably includes additional points of cam action, useable separately or together, to prevent early translation at the initiation of flexion, and a distinct point of cam action to prevent a dislocation of the femoral component over the tibial post which often occurs in cruciate-substituting designs. The preferred embodiment includes three distinct point of cam action. The first is preferably located substantially where existing cams are found, namely, at a point spaced apart a slight distance posteriorly relative to the post in full extension. A second point of cam action is located immediately adjacent the posterior aspect of the superior post to minimize and, ideally, prevent anterior translation at the initiation of flexion.

Abstract: A knee prosthesis has a medial condyle (1) and a lateral condyle (5), the running surfaces (2) of which and the counter-surfaces A, B of which that lie on a tibia platform (3) are sections of spherical surfaces with radii R1, R2, with their center M1′ and M2′ forming in their vertical projection onto the counter-surfaces A, B the points M1, M2. The lateral counter-surface B belongs to a lateral meniscus part (7) which, guided on a plane (13) of the tibia platform, is pivotal with the point M2 on a circular arc with radius R3 about the point M1, with the radius R3 corresponding to the distance a of the centers M1′, M2′.

Abstract: An implant for installation into a portion of an articular surface includes a protrusion configured to cover an un-excised portion of articular surface proximate to the implant. Another implant may form a cavity to allow the un-excised portion of articular surface to remodel over a perimeter edge of the implant. The implant may also include indentations such as grooves to promote articular cartilage remodeling over a portion of the load bearing surface of the implant. An elongated or non-round implant is also provided having two opposing concentric arcuate shaped sides, as well as a method to seat such an implant in an articular surface. A method for seating an implant without cutting articular cartilage is also provided.

Abstract: The present invention provides tools and methods for mapping and measuring the articular surface of a joint (or of any bony surface) and for fabricating a prosthetic device based on this recorded data. In one embodiment, once the defect of the chondral surface has been identified, a guide pin is inserted arthroscopically. A fixation screw is driven into the subchondral bone in relation to a reference axis that is approximately central to the defect, the fixation device also serving to define a tangent point to the surrounding articular surface. A further cylindrical proximal extension of the screw that eventually serves as a fixation element for the surface prosthetic is concealed with a cover or plug. The depth positioning of the cover or plug establishes an origin or reference point for all future measuring, cutting, and prosthetic machining operations. A measuring tool having a static post that establishes the axial location of origin is inserted on the reference axis.

Abstract: A tibial prosthesis includes a tibial platform having a medial-lateral center and an inferior surface matable with a resected proximal tibia, and a modular keel that is fixable to the inferior surface and adjustable in a medial-lateral direction with respect to the medial-lateral center of the tibial platform.

Abstract: A knee prosthesis including a tibial component and a meniscal component adapted to be engaged through the tibial component through an asymmetrical engagement.

Abstract: Improved bone cutting guides enable a surgeon to better gauge required resection characteristics. In one embodiment at least a portion of the guide is transparent, thereby enabling the user to optimize cut estimates and to visualize the resection as it is being performed. In another embodiment, at least a portion of the outer surface of the body is shaped to interact with another bone or prosthetic element associated with a joint, thereby enabling the device to function both as a trial and as a cutting guide. In this embodiment as well the guide may be at least partially transparent to improve visualization. Although primarily intended for use in femoral-side knee arthroplasty, the invention is applicable to any procedure which might benefit from improved bone-cutting accuracy.