Abstract:
An articulated knee prosthesis in which a femoral implant has a condyle section and a femoral stem that is cemented into the femur. A tibial implant carries a tibial plateau section on which is mounted a stop plate for engaging the condyle section and arresting movement of the knee beyond its fully extended position. The tibial implant includes a tibial stem that is cemented into the tibia. A pivotal connection between the two implants is positioned posteriorly of the implant and at an elevation above a lowermost point of the condyle section (when the implants are fully extended). The pivot axis of the connection and the stems are positioned with respect to each other so that upon the implantation of the implant, the patient's tibia is moved in an anterior direction as compared to the normal anatomical position of the tibia relative to the femur. At least a portion of the hinged connection, which frequently includes the pivot axis, is located posteriorly of portions of the femur proximate the knee joint to maximize the arc through which the knee can be flexed.
Abstract:
A knee joint endoprosthesis includes a femoral component, a tibial component and a slide bearing providing for relative pivotal movement between the components and formed of a femoral bearing half carried by the femoral component and a tibial bearing half carried by the tibial component. The bearing halves are arranged for being pressed to one another while free from being connected to one another. There is further provided an arrangement for cardanically guiding the bearing halves with respect to one another with degrees of freedom in horizontal and vertical directions.
Abstract:
A femoral pin for a hip prosthesis, wherein the pin is in the form of a plurality of funicular elements, or strands, issuing from a hilt member. The strands have graduated lengths, are grouped according to their lengths and have their ends opposite the hilt member connected together. The longest strands form the outer contour of the pin member and the shorter strands are within this tapered contour.
Abstract:
A prosthetic implant for replacement of the proximal end of the tibia includes a metal anchor member which is cemented into the intramedullary canal of the tibia and a replaceable high density polyethylene articulation member which is pinned to the anchoring member. The anchoring member and the replaceable articulation member slidably fit together by movement in a lateral direction by means of a dovetail fitting and a raised tab portion is provided as a stop means in order to assure proper positioning of one member with respect to the other. Once the two members are properly aligned, a vertical pin is inserted therethrough and is secured in position by a two prong horizontal clip arrangement which inserts through the articulation member and clips about a reduced diameter portion of the vertical pin member. Notches are provided in both the anchoring member as well as the replaceable articulation member for clearance of ligaments and the outer peripheral edge of the anchoring member includes a depending sharp lip and a depending groove therebehind which facilitate cementing of the anchoring member in place by compacting acrylic bone cement into the prepared surface of the tibia.
Abstract:
There is provided a metacarpal-phalangeal joint replacement having two members, one for insertion into each of the respective bones in the joint. Each member defines a tail and a head, and the two heads are adapted to fit with each other in such a way that when the finger is extended, the joint and thus the finger have a limited degree of lateral freedom to swing from side to side, whereas when the finger is flexed, this lateral freedom is considerably restricted. This variation is brought about by making the face of one head generally protuberant, and the face of the other head generally recessed or channeled. The "match" in contour between the two faces thus varies during the pivoting of the one member with respect to the other, between a substantially complementary fit when the finger is flexed, to a "loose" or "wobble" fit when the finger is extended.
Abstract:
The bone implant is made from elements which have different mechanical properties and which are maintained out of contact from each other by means of a plastic member. The plastic member is disposed in and fills a gap formed by the implant elements. In addition, the plastic member has thin-walled extensions which are engaged in narrowing sections at the outer boundaries of the gap. These extensions guard against any creep in the plastics member under the forces imposed on the plastics member during stressing of the bone implant.
Abstract:
The shaft portion of an artificial hip joint intended for cement-free anchoring in a femur which is generally rectangular in cross-section and is provided with outwardly projecting steps for direct transfer of axial forces between the shaft and the bone tissue, one half of the steps being transversely inclined with respect to the shaft axis with the other half of the steps inclined in the opposite direction by an equal amount to prevent rotation of the shaft as a result of the development of equal and opposite components of force.
Abstract:
A modular prosthesis assembly for replacement of at least part of a joint and part of a bone shaft including a mounting component provided with a connection portion and at least two joint components of similar shape but different dimensions and which can be connected alternatively to the mounting component, each of the joint components having an engagement portion and a connection part adapted for connection to the connection portion of the mounting component, the joint components each providing part of a bone shaft and part of a joint which can cooperate with an appropriate part of a natural or artificial joint.
Abstract:
A patellar flange for a knee joint prosthesis comprising a curved base and a pair of condylar runners, one of said condylar runners being attached to each lateral side of the base and extending outwardly anteriorly therefrom diverging from each other and converging to the base superiorly and a femoral knee joint prosthesis containing the flange.
Abstract:
A prosthesis for the surgical replacement of a dysfunctional knee joint. The prosthesis includes a tibial platform, one or two tibial bearing inserts, and a femoral component.In a unicompartmental embodiment of the invention, the tibial platform includes a spike for securing the tibial platform to the tibia. The tibial platform, in the unicompartmental embodiment, includes a track, which may be curved, and which is slidably engaged in dovetail fashion by a tibial bearing insert. The superior surface of the tibial bearing insert is concave spherical, designed to slidably engage the inferior surface of the femoral component. The inferior surface of the femoral component is generally convex spherical, with radius of curvature slightly smaller than the radius of curvature of the tibial bearing insert.In a bicompartmental or tricompartmental embodiment of the invention, the tibial platform includes two tracks, each of which may be curved, and each of which slidably engages in dovetail fashion a tibial bearing insert. The two tibial bearing inserts each engage, via their superior concave spherical surfaces, mating inferior convex surfaces of the femoral component. The two curved tracks are in general not concentric; rather, the center of each falls on a line normal to the plane of such curved track and passing through the center of curvature of the concave spherical surface of the tibial bearing insert of the other curved track.