Abstract: A knee prosthesis includes a femoral component, a tibial component, a bearing and a control arm. The bearing is in articular bearing engagement with the femoral component and in sliding and rotational bearing engagement with the tibial component. Movement of the bearing relative to the tibial component is controlled by a control arm. The anterior extreme of the control arm includes a removable stop for limiting anterior movement of the bearing relative to the tibial component.

Abstract: A knee prosthesis includes a femoral component, a tibial component, a bearing and a control arm. The bearing is in articular bearing engagement with the femoral component and in sliding and rotational bearing engagement with the tibial component. Movement of the bearing relative to the tibial component is controlled by a control arm. Anterior and posterior extremes of the control arm include stops for limiting anterior and posterior movement of the bearing relative to the tibial component. At least one of the stops is removable relative to the control arm to facilitate implantation.

Abstract: A knee prosthesis includes a femoral component, a tibial component, a bearing and a control arm. The bearing is in articular bearing engagement with the femoral component and in sliding and rotational bearing engagement with the tibial component. Movement of the bearing relative to the tibial component is controlled by a control arm. Anterior and posterior extremes of the control arm include stops for limiting anterior and posterior movement of the bearing relative to the tibial component. At least one of the stops is removable relative to the control arm to facilitate implantation.

Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion.

Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion. Roll back substantially avoids climb of the femoral component on the bearing during flexion and hence reduces shearing forces on the post.

Abstract: A knee prosthesis includes a femoral component, a tibial component, a bearing and a control arm. The bearing is in articular bearing engagement with the femoral component and in sliding and rotational bearing engagement with the tibial component. Movement of the bearing relative to the tibial component is controlled by a control arm. The anterior extreme of the control arm includes a removable stop for limiting anterior movement of the bearing relative to the tibial component.

Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion.

Abstract: A prosthetic replacement knee joint includes a tibial component, a femoral component, a bearing and a control arm. The tibial component has a superior bearing surface and a conical recess extending into the superior bearing surface. The bearing has an inferior surface slidably engaged with the superior surface of the tibial component and formed with a dovetailed groove therein. The bearing also has a concave superior surface. A notch extends into the posterior extreme of the bearing. The femoral component has a pair of convex arcuate condyles in articular bearing engagement with the superior surface of the bearing. The femoral component also includes a posterior notch having a minor medial-lateral width at the inferior surface of the femoral component and a major width at more superior locations on the femoral component. The control arm has a conical bearing rotatable positioned in the conical recess of the tibial component.

Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion. Roll back substantially avoids climb of the femoral component on the bearing during flexion and hence reduces shearing forces on the post.

Abstract: A knee joint prosthesis includes femoral and tibial components, a bearing and a control arm. The bearing includes an inferior surface in sliding bearing engagement with the tibial component and a superior surface in articular bearing engagement with the femoral component. A notch extends into the posterior end of the bearing and a groove extends anteriorly from the notch in the inferior surface of the bearing. The posterior portions of the femoral component define a cam box having medial and lateral walls and a cam extending therebetween. The control arm is slidably engaged in the groove of the bearing and pivotally engage on the tibial component. The control arm further includes a post that extends into the cam box. The post includes a cam surface that engages the femoral cam to generate roll back of the femoral component on the bearing during flexion. Roll back substantially avoids climb of the femoral component on the bearing during flexion and hence reduces shearing forces on the post.

Abstract: A knee joint prosthesis is provided. The prosthesis includes a femoral component for mounting to the distal end of a femur, a tibial component for mounting to the resected proximal end of the tibia and a bearing disposed between the femoral and tibial components. The tibial component includes a superior bearing surface with a recess extending distally into the bearing surface. The bearing includes an inferior bearing surface for engagement on the superior bearing surface of the tibial component. Additionally, the bearing includes a projection that is rotatably engaged in the recess of the tibial component. Rotation of the bearing relative to the tibial component is limited by a stop extending from the superior bearing surface of the tibial component. The stop is engaged in a slot formed in the inferior surface of the bearing. The slot is concentric about the rotational axis and extends through an arc consistent with the desired maximum range of rotation.

Abstract: A tibia fixturing device comprises a metal tray formed with annularly spaced recesses in its underside at a depth of at least about 1.5 mm and from which a stem depends for axial insertion into a tibia conical cavity. The stem has a circular cylindrical portion proximal the tray and a conical portion distal the tray. Fins radially extend from the stem cylindrical portion and penetrate the tibia to provide some torsional resistance. Axially extending channels are formed about the stem periphery which channels have bottom surfaces parallel to the stem axis to provide further torsional resistance. The channels are arranged to not interlock with the cement in the axial direction to permit the cement to separate first from the device during axial removal of the device from the bone. The fins have inclined edges distal the tray and inclined radial outer edges to align and center the stem to the bone cavity edge.

Abstract: The prosthetic knee joint is provided for resisting valgus-varus movements. The joint includes a femoral component having a superior bone engaging surface and an inferior bearing surface. A posterior notch extends anteriorly into the posterior end of the femoral component. The prosthetic knee joint further includes a tibial component having an inferior bone engaging surface and a superior bearing surface. A plastic bearing is disposed between the femoral and tibial components. An inferior surface of the plastic bearing is in bearing engagement with the superior surface of the tibial component. A superior bearing surface of the plastic bearing is in articular bearing engagement with the bearing surface of the femoral component. The bearing includes a post projecting proximally from the superior surface. The post is slidably received in the posterior notch of the femoral component and resists valgus-varus moments imposed upon the joint.

Abstract: A femoral component of a knee prosthesis includes a bearing surface defined by a smooth, continuous surface which in one embodiment is entirely formed by a series of three segments of surfaces of revolution, the respective shapes of which are generated by rotating a common generating curve around three separate generating axes at respective pairs of major generating radii and through respective angles of rotation. The central segment of the surfaces of revolution constantly maintains the substantially same contact configuration with the superior bearing surface of a bearing insert over a range extending from full extension (0.degree. of flexion) to at least 45.degree. of flexion and up to 105.degree. of flexion. The maintenance of the substantially same contact configuration ensures area, point or line contact between the articulating surfaces which reduces contact stress and wear in flexion.

Abstract: Joint endoprostheses, disclosed in the context of a total knee prosthesis, incorporate a first element for rigid connection to a first bone, the first element having an articulating surface; a second element for rigid connection to a second bone, the second element having a bearing surface which engages the articulating surface; wherein the engagement of the articulation surface with the bearing surface at any degree of relative rotation therebetween is reflected by a substantially constant contact configuration, the relative rotation of the device being accompanied by displacement of the bones toward and away from each other.

Abstract: Joint endoprostheses, disclosed in the context of a total knee prosthesis, incorporate a first element for rigid connection to a first bone, the first element having an articulating surface; a second element for rigid connection to a second bone, the second element having a bearing surface which engages the articulating surface; wherein the engagement of the articulation surface with the bearing surface at any degree of relative rotation therebetween is reflected by a substantially constant contact configuration, the relative rotation of the device being accompanied by displacement of the bones toward and away from each other.

Abstract: A tibia fixturing device comprises a metal tray formed with annularly spaced recesses in its underside at a depth of at least about 1.5 mm and from which a stem depends for axial insertion into a tibia conical cavity. The stem has a circular cylindrical portion proximal the tray and a conical portion distal the tray. Fins radially extend from the stem cylindrical portion and penetrate the tibia to provide some torsional resistance. Axially extending channels are formed about the stem periphery which channels have bottom surfaces parallel to the stem axis to provide further torsional resistance. The channels are arranged to not interlock with the cement in the axial direction to permit the cement to separate first from the device during axial removal of the device from the bone. The fins have inclined edges distal the tray and inclined radial outer edges to align and center the stem to the bone cavity edge.

Abstract: A femoral component with a femoral stabilizing implanted rod has condylar surfaces of different radii which mate with a thermoplastic bearing. A mating tibial platform is stabilized in the tibia with a rod, the bearing translating on the platform in the posterior-anterior directions in response to knee flexion and extension. The bearing bears the full extension load on congruent articulating contact regions with the condylar surfaces and lesser flexion loads via incongruent articulating contact. A hinge assembly is pinned to the femoral condylar component through a head having a depending shaft fixed to a thermoplastic tapered bearing axially floating and rotatably movable in a tibia platform component mating cavity. The head passes through the bearing and stops the bearing translations at extreme posterior and anterior positions.

Abstract: A prosthesis tibial bearing of thermoplastic material has a planar surface which engages the mating planar surface of a second prosthesis component such as the tibial platform. The typically metal platform edge wipes across the inner surface region of the bearing causing deformation of the bearing surface. This deformation causes stress magnification in the bearing at the platform edge region. The edge region of the platform planar surface is tapered to provide a gradual curved ramp between a relatively small corner radius at the platform edge and the platform planar surface, the tapered region being tangential to the edge radius and to the platform planar surface. The stress concentration increase at the edge region of the bearing is reduced at the platform edge region to below 100% and preferably to about 25% of the stress value between the bearing and the platform in the region interior the platform edge.

Abstract: A tibia fixturing device comprises a metal tray formed with annularly spaced recesses in its underside at a depth of at least about 1.5 mm and from which a stem depends for axial insertion into a tibia conical cavity. The stem has a circular cylindrical portion proximal the tray and a conical portion distal the tray. Fins radially extend from the stem cylindrical portion and penetrate the tibia to provide some torsional resistance. Axially extending channels are formed about the stem periphery which channels have bottom surfaces parallel to the stem axis to provide further torsional resistance. The channels are arranged to not interlock with the cement in the axial direction to permit the cement to separate first from the device during axial removal of the device from the bone. The fins have inclined edges distal the tray and inclined radial outer edges to align and center the stem to the bone cavity edge.