293 results about "Knee prosthesis" patented technology

A knee prosthesis, methods of implanting the prosthesis, method of treating arthritis of the knee, and a kit therefore are provided. The prosthesis answers many of the limitations of current knee prosthetic devices by providing a two-component (or alternatively, an optional three-component) device, as either a single structure, or as separate pieces. One of the components is constructed of low friction material, while the second is composed of a weight-dissipating cushioning material; the optional third component is constructed of low friction material. The prosthesis is initially attached to surrounding soft tissue in the knee by biodegradable sutures; it is held permanently in place by fibrous ingrowth into a porous collagen rim in the cushioning component. Major improvements provided by the present invention over currently available prostheses include minimal incisions, minimal or no bone cuts, minimal overall dissection (these improvements lead to shorter hospital stays and rapid rehabilitation and fewer potential for side effects), less prosthetic wear, greater longevity, fewer activity restrictions, able to be used on young, large, active patients, ease of revision, ease of conversion into a total knee arthroplasty if needed.

Knee prostheses featuring components that more faithfully replicate the structure and function of the human knee joint in order to provide, among other benefits: greater flexion of the knee in a more natural way by promoting or at least accommodating internal tibial rotation in a controlled way, replication of the natural screw home mechanism, and controlled articulation of the tibia and femur respective to each other in a more natural way. In a preferred embodiment, such prostheses include an insert component disposed between a femoral component and a tibial component, the insert component preferably featuring among other things a reversely contoured postereolateral bearing surface that helps impart internal rotation to the tibia as the knee flexes. Other surfaces can also be specially shaped to achieve similar results, preferably using iterative automated techniques that allow testing and iterative design taking into account a manageable set of major forces acting on the knee during normal functioning, together with information that is known about natural knee joint kinetics and kinematics.

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.

Implantable prosthetic devices are provided for controlled drug delivery, for orthopedic and dental applications. The device may include a prosthetic device body having at least one outer surface area; two or more discrete reservoirs located in spaced apart positions across at least a portion of the outer surface area, the reservoirs formed with an opening at the surface of the device body and extending into the device body; and a release system disposed in the reservoirs which comprises at least one therapeutic or prophylactic agent, wherein following implantation into a patient the therapeutic or prophylactic agent is released in a controlled manner from the reservoirs. The prosthetic device body preferably is a joint prosthesis or part thereof, such as a hip prosthesis, a knee prosthesis, a vertebral or spinal disc prosthesis, or part thereof. Optional reservoir caps may further control release kinetics.

The invention relates to a knee joint prosthesis 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, a guide post and a mechanically reconstructed 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 guide post extends from the tibial component. The mechanically reconstructed ligament is coupled to both the tibial component and the femoral component to prevent the knee joints from dislocating and guiding the femoral component along a desired path during extension and flexion.

The invention relates generally to a method for implanting a uni-condylar knee prosthesis. The method includes steps for preparing the bone surfaces of both the femoral and tibial effected compartments. The femoral compartment is prepared by making a distal cut, a posterior cuts and a posterior chamfer cut. Holes that correspond to posts on the femoral component are also prepared. The tibial compartment is prepared using a cutting guide and following the sclerotic bone formation on the proximal tibia. At least one hole is prepared in the sloped cut tibial surface to use for alignment when cementing the tibial component that has an alignment peg.

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.

A knee prosthesis is provided for use in knee arthroplasty. In one exemplary embodiment, the present invention provides a tibial prosthesis having a tibial baseplate with a fixed medial bearing component and a mobile lateral bearing component. In one exemplary embodiment, the lateral bearing component is secured to the lateral portion of the tibial baseplate utilizing at least one prosthetic ligament. Additionally, in one exemplary embodiment, a stop is provided to limit anterior or posterior movement of the lateral bearing component relative to the tibial baseplate. For example, the stop may be defined by cooperating shoulders formed on the lateral bearing and the tibial baseplate.

A modular prosthetic knee system used to replace the natural knee. The system includes a femoral knee prosthesis and a tibial knee prosthesis. Both prostheses are formed of modular components that are connectable in-vivo to form the prosthetic knee system. The femoral knee prosthesis includes two separate components, a lateral condyle and medial condyle; and the tibial knee prosthesis includes a multiple separate components, a medial baseplate, a lateral baseplate, a medial insert, and a lateral insert. The medial and lateral baseplate are connectable to form a complete baseplate with the medial and lateral inserts connectable to the complete baseplate.

An improved knee prosthesis includes a ceramic tibial component for articulation with natural or prosthetic (re-surfaced) femoral surfaces. The ceramic tibial component is provided in the form of a ceramic monoblock adapted for fixation relative to the patient's tibial bone, or alternately in the form of a ceramic bearing insert component carried by a tibial baseplate member which is adapted in turn for fixation relative to tibial bone. In either form, the ceramic tibial component includes at least one upwardly concave articulation surface for movable bearing engagement by a generally convex or condylar shaped femoral articulation surface. The ceramic tibial component provides improved wear characteristics with extended service life.

Knee prosthesis comprising a metal base secured to an anchoring rod for fixing it into a tibia of a patient. A plastic tibia plate is freely slidable over the base. The metal base and the tibia plate are equipped with a guide mechanism defining a center of rotation offset from that of a tibia bone axis, so as to allow the plate to slide in rotation over the base. The guide mechanism is positioned a given distance from the center of rotation. The metal base comprises an upstand in the shape of an arc of a circle having a central part secured to lateral edges which are shorter than the central part. The tibia plate comprises, on a lower face thereof, a housing in the shape of an arc of a circle.

A knee prosthetic including a tibial component defining medial and lateral concavities shaped to receive medial and lateral femoral condyles of the femur. The concavities have first portions for contact with the condyles during normal knee flexion and second portions for contact with the condyles during deep, or high, knee flexion. The medial concavity can include a conforming boundary that encompasses at least the first and second portions, wherein an area inside the conforming boundary has a generally flat surface. The flat surface allows the medial femoral condyle to slide and rotate posteriorly during high knee flexion. The conforming boundary can have a generally triangular shape with an apex extending anteriorly and a relatively wider base extending posteriorly, wherein the apex includes the first portion and the base includes the second portion. The relatively wider base portion advantageously allows additional area for posteriorly directed articulating contact during high knee flexion.

A combination of a first assembly for guiding resection of a femur and tibia of a knee joint and a second assembly including femoral and tibial knee components. The combination of the first assembly and the second assembly provides optimal placement and positioning of the femoral and tibial knee components to achieve near-normal knee kinematics and tension. The preparation for and placement of the prosthetic knee components provides medial-pivoting kinematics mimicking that of the natural knee thereby promoting improved outcome for the patient.

A patellar implant for total or partial prosthesis of the knee joint incorporates an outer articular surface and an inner articular surface provided to cooperate respectively with an outer side and an inner side of a femoral trochlea or of a femoral prosthetic component. The inner and outer articular surfaces are separated by a transition ridge which is curved, as viewed from a front of the implant, so as to be concave facing the outer articular surface. The outer articular surface is concave in a plane parallel to a sagittal plane and in a transverse plane of the knee joint.

A knee prosthesis is provided that allows for increased flexion. The knee prosthesis includes (a) a femoral component adapted to fit on a distal end of the femur which includes a lateral condylar structure and a medial condylar structure and (b) an intermediate structure configured to cooperate with a femoral component of a knee prosthesis. The intermediate structure includes at least one surface for contacting the femoral component and a transition of a sagittal curvature of the at least one contact surface from a concave surface into a convex surface at the contact interface of the femoral component and the intermediate structure when the knee is flexed at approximately 120° to 140°. The knee prosthesis minimizes impingement on the femoral posterior cortex in deep flexion, increases the dislocation safety factor and allows for easier reengagement of the articular surface should the femoral component externally rotate off of the tibial plateau.

In a knee prosthesis, the condylar surfaces of a femoral component engage corresponding articular surfaces of a tibial component along prescribed tracks of predetermined curvature which enable relative rotation between the femoral component and the tibial component about a longitudinal axis during articulation of the knee prosthesis, and at least the condylar surfaces or the articular surfaces are flared in a direction away from corresponding articular surfaces or condylar surfaces along engaged posterior and anterior portions of the condylar surfaces and articular surfaces to provide an increased area of contact in deep flexion and in extended hyperextension for reducing contact stresses and concomitant wear while militating against unwanted distraction of the knee prosthesis. In addition, the radius of curvature of the condylar surfaces is reduced along posterior portions of the condylar surfaces to further avoid distraction of the knee prosthesis in deep flexion, thereby enabling deep flexion with greater ease and without excessive contact forces between the femoral component and the tibial component in deep flexion.

A knee replacement system includes a proximal tibial posterior camming portion defined by a first radius of curvature with a first origin in a first medio-lateral plane, a distal tibial posterior camming portion defined by a second radius of curvature with a second origin in a second medio-lateral plane, an anterior femoral camming portion of a posterior cam defined by a third radius of curvature with a third origin in the first medio-lateral plane, and a posterior femoral camming portion of the posterior cam and defined by a fourth radius of curvature with a fourth origin in the second medio-lateral plane, wherein the second origin is closer to the lateral tibial portion than the first origin, or the fourth origin is closer to the medial femoral portion than the third origin.

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.

A knee prosthesis is provided that allows for increased flexion. The knee prosthesis includes (a) a femoral component adapted to fit on a distal end of the femur which includes a lateral condylar structure and a medial condylar structure and (b) an intermediate structure configured to cooperate with a femoral component of a knee prosthesis. The intermediate structure includes at least one surface for contacting the femoral component and a transition of a sagittal curvature of the at least one contact surface from a concave surface into a convex surface at the contact interface of the femoral component and the intermediate structure when the knee is flexed at approximately 120° to 140°. The knee prosthesis minimizes impingement on the femoral posterior cortex in deep flexion, increases the dislocation safety factor and allows for easier reengagement of the articular surface should the femoral component externally rotate off of the tibial plateau.

Total prosthesis of a knee including a femoral element fitted with two condyles, a first of the condyles being external, a second of the condyles being internal, and a tibial plateau fitted with custom-made recesses to hold the condyles, wherein at least one of the condyles is integral on one of its sides with a convex cam ensuring posterior stability of the prosthesis. The tibial plateau has at least one track placed in the immediate vicinity of the recess holding the condyle integral with the cam, the at least one track being circumscribed by at least one curved abutment and at least one horizontal recess between posterior and anterior extremities of the tibial plateau. Provision is made between the condyles of the femoral element and the recesses of the tibial plateau for a free space and a notch for passage of a posterior cruciate ligament of a knee.

A mobile bearing knee prosthesis apparatus includes a tibial plate. The tibial plate includes a medial lobe and a lateral lobe conjoined in a dividing plane. The apparatus further includes a tibio-femoral insert and a stud-like protuberance extending from the tibial plate into the tibio-femoral insert. The stud-like protuberance includes a protuberance sidewall positioned in the tibio-femoral insert. The protuberance sidewall is bisected by the dividing plane and includes a pair of opposing eccentric convex arcuate portions, and the tibio-femoral insert is moveable relative to the tibial plate about an axis medially disposed from the dividing plane. A mobile bearing knee prosthesis apparatus includes a tibial plate and a tibio-femoral insert coupled to the tibial plate. The tibio-femoral insert includes a generally posteriorly positioned chamfered superior surface and defines a generally posteriorly positioned generally U-shaped space bounded at least in part by the chamfered surface.

The present invention relates to one or more tibial spacer blocks used during knee arthroplasty, each configured to be temporarily positioned upon a resected proximal portion of a tibia (essentially mimicking the tibial component of the knee prosthesis), for performing a range of motion analysis and for checking flexion and extension gaps prior to cutting the distal or posterior femur. Preferably, the spacer blocks each include an attachment arrangement configured and arranged to mate with a complementary attachment arrangement of an alignment tower and / or a femoral cutting guide. The alignment tower, which is configured to be used with an alignment rod, is used for verifying the alignment of the limb's mechanical axis when the spacer block is positioned between the tibia and the femur. The femoral cutting guide is used for guiding a cutting member into proper orientation for resecting a distal or posterior portion of a femur.

The invention relates to an automated speed-adaptive and patient-adaptive control scheme and system for a knee prosthesis. The control scheme and system utilizes sensory information measured local to the prosthesis to automatically adjust stance and swing phase knee resistances to a particular wearer under a wide variety of locomotory activities. Advantageously, no patient-specific information needs to be pre-programmed into the prosthetic knee by a prosthetist or the patient. The system is able to adapt to various types of disturbances once the patient leaves the prosthetist's facility because it is patient-adaptive and speed-adaptive.

Method for selecting one or several knee prosthesis elements, by acquiring spatial data concerning spacing and tensioned femorotibial position, including the corresponding HKA angle, for at least three angular positions, of 20°, of 0°, and of the order of 90° in flexion, processing the data thus obtained to verify whether the HKA angles are substantially equal and included within the tolerable limits, and processing the data, in particular those corresponding to extension and flexion of 90° to determine the dimensions and / or positions of the implant.

A knee prosthesis for unicompartmental implantation into a knee joint is implantable without requiring bone resection and includes a body free of any means of fixation to a portion of knee joint, anatomy and having a substantially elliptical shape in plan and a pair of contoured opposed faces including a convex face and a concave face. A peripheral edge extends between the faces and includes a first side, a second side opposite the first side, a first end and a second end opposite the first end. A first dimension D is defined by the first end and the second end. A second dimension F is defined by the first side and the second side. The dimension F is from about 0.25 to about 1.5 of the dimension D.

The present invention relates to a system and method for adjusting a thickness of a prosthesis (e.g., a knee implant). In one embodiment, a knee prosthesis for implantation in a patient is provided, comprising: a tibial tray, wherein the tibial tray comprises an upper surface and a lower surface, and the lower surface of the tibial tray is disposed adjacent a tibia of the patient; a tibial insert, wherein the tibial insert comprises an upper surface and a lower surface; a tibial spacer, wherein the tibial spacer comprises an upper surface and a lower surface, and wherein the tibial spacer is disposed between the tibial tray and the tibial insert such that the lower surface of the tibial spacer is adjacent the upper surface of the tibial tray and the upper surface of the tibial spacer is adjacent the lower surface of the tibial insert; and at least one locking mechanism, wherein the locking mechanism locks the tibial spacer to the tibial tray to form a locked spacer / tray assembly such that the locking mechanism substantially prohibits at least relative up-down movement between the tibial spacer and the tibial tray when the locked spacer / tray assembly is implanted in the patient. In one example, the locking mechanism may further lock the tibial spacer to the tibial insert to form a locked insert / spacer / tray assembly such that the locking mechanism substantially prohibits at least relative up-down movement between the tibial spacer and the tibial insert when the locked insert / spacer / tray assembly is implanted in the patient. In another embodiment, a method for implanting a knee prosthesis in a patient is provided, comprising: providing a tibial tray, wherein the tibial tray comprises an upper surface and a lower surface, and the lower surface of the tibial tray is disposed adjacent a tibia of the patient; providing a tibial insert which has a shelf life and which is not readily re-sterilizable after the shelf life has expired, wherein the tibial insert comprises an upper surface and a lower surface; and providing a tibial spacer which has a shelf life and which is re-sterilizable after the shelf life has expired, wherein the tibial spacer comprises an upper surface and a lower surface, and wherein the tibial spacer is disposed between the tibial tray and the tibial insert such that the lower surface of the tibial spacer is adjacent the upper surface of the tibial tray and the upper surface of the tibial spacer is adjacent the lower surface of the tibial insert.