Abstract: A recess-ramp knee joint prosthesis comprising a femoral and a tibial component is configured to reproduce normal kinematics and function. Asymmetric condular surfaces and a cupola of the femoral component interact with corresponding dished surfaces and a ramp of the tibia thereby duplicating the behavior of the anatomical knee.

Abstract: An artificial knee joint is described that includes a femoral component with a specially shaped bearing surface and a tibial component, whose surface interacts with the femoral surfaces. The interaction provides for the required motion and stability characteristics. The interaction between the femoral and tibial surfaces is such that as the knee is flexed to maximum, the femoral component moves posteriorly on the tibial surface, by an amount similar to that in the anatomic knee. The opposite motion, roll forward of the femur from a fully flexed to a more extended position, is accomplished by varying the outward radii of the lateral and medial femoral bearing surfaces, together with a ramp on the postero-lateral and postero-medial regions of the tibial surfaces.

Abstract: An artificial knee joint that includes a femoral component with a specially shaped bearing surface and a tibial component, whose surface interacts with the femoral surfaces. The interaction provides for the motion and stability characteristics of the anatomic knee. The interaction between the femoral and tibial surfaces is such that as the knee is flexed to maximum, the femoral component moves posteriorly on the tibial surface, more so on the lateral side than on the medial side. This is accomplished by the interaction of a projecting tibial post inside a cupola in the center of the femoral component, and by the saggital radius on the medial side being smaller than that on the lateral side. The prevention of anterior sliding of the femur on the tibia in early flexion is accomplished by the interaction between a distal-anterior recess on the medial side of the femur and an apposing raised pad on the tibial surface.

Abstract: A replacement knee implant has a femoral implant and a tibial implant, each of which are inset in a bone surface. The tibial implant is generally elongated with one end rounded and an opposite end conforming to the shape of the tibia, and is made of a metal alloy or a ceramic. The upper surface is dished while the lower surface is planar and can be parallel or sloped relative to the upper surface, and can have a keel for fixation. The femoral implant for implementation in a femoral condyle is rounded such that, when implemented, the femoral implant is flush at the anterior and posterior sides and protruding away from the femur between the anterior and posterior ends. The femoral implant can have an elongated keel for extending into the femur, and can be made from a highly cross-linked polyethylene.

Abstract: A replacement knee implant has a femoral implant and a tibial implant, each of which are inset in a bone surface. The tibial implant is generally elongated with one end rounded and an opposite end conforming to the shape of the tibia, and is made of a metal alloy or a ceramic. The upper surface is dished while the lower surface is planar and can be parallel or sloped relative to the upper surface. The femoral implant for implementation in a femoral condyle is rounded such that, when implemented, the femoral implant is flush at the anterior and posterior sides and protruding away from the femur between the anterior and posterior ends. The femoral implant can have an elongated keel for extending into the femur, and can be made from a highly cross-linked polyethylene.

Abstract: A recess-ramp knee joint prosthesis comprising a femoral and a tibial component is configured to reproduce normal kinematics and function. Asymmetric condular surfaces and a cupola of the femoral component interact with corresponding dished surfaces and a ramp of the tibia thereby duplicating the behavior of the anatomical knee.

Abstract: An artificial knee joint is described that includes a femoral component with a specially shaped bearing surface and a tibial component, whose surface interacts with the femoral surfaces. The interaction provides for the required motion and stability characteristics. The interaction between the femoral and tibial surfaces is such that as the knee is flexed to maximum, the femoral component moves posteriorly on the tibial surface, by an amount similar to that in the anatomic knee. The opposite motion, roll forward of the femur from a fully flexed to a more extended position, is accomplished by varying the outward radii of the lateral and medial femoral bearing surfaces, together with a ramp on the postero-lateral and postero-medial regions of the tibial surfaces.

Abstract: A bone surgery device with a reciprocating cutting head. The device comprises several sets of shaping surfaces sometimes including cutting blades, which are located and oriented so as to shape the distal end of the femur and the proximal end of the tibia for total knee replacements and unicompartmental knee replacements. The device, which may be hand directed or aided by spatial and directional guiding mechanisms or an optical navigation system, may also include both coolant supply for controlling heat during bone cutting and shaping, and a suction method for carrying away fluid and debris. The device is substantially configured to the artificial joint component to be attached thereto.

Abstract: A condylar total knee replacement prosthesis is disclosed having interacting guide surfaces for control of anterior-posterior displacement. The prosthesis comprises a femoral component (1) having a pair of condylar surfaces (2,3), a tibial component having a tibial platform (4) and a bearing component interposed between the femoral and tibial components. A femoral guide surface (5) is located between the condyles and engages with a tibial guide surface (8) to cause the femoral component to displace posteriorly during flexing movements and displace anteriorly during extending movements. The femoral guide surface is offset posteriorly and downwardly from the center of major curvature of the femoral condyles.

Abstract: The prosthesis comprises a femoral component (2) having at least one substantially spheroidal condylar bearing surface (10,11), a tibial component (6) including a tibial platform (20), and a plastics meniscal component (7) located between the condylar bearing surface (10,11) an the tibial component (6) and being slidable on the platform (20). The meniscal component (7) is retained on a guide (23) upstanding from the platform (20). The guide (23) includes a post (24) and a cap (25) which is a snap-fit in a recess (30) in the meniscal component (7). The guide (23) is slidable in a track (32) within the meniscal component (7) so that movement of the meniscal component (7) in the anterior/posterior direction (A-P) is limited by impingement of the meniscal component (7) on the post (24) and/or on a rail member (21) projecting from the surface of the tibial platform (20).

Abstract: A total knee replacement prosthesis (TKR) is provided in which a pintle hinge enables the knee to pivot about a horizontal axis. A degree of rotational movement about a vertical axis is provided by fabricating the tibial component in at least two parts. One part is attached to the hinge and includes a stem portion which is designed to be rotatable with a hollow shell adapted to be fixed into the tibia. The hinge portion is standardized and is designed to receive femoral and tibial stem portions having dimensions to suit a particular patient.

Abstract: The invention provides means for evaluating the fit of a knee replacement prosthesis on a resected tibial surface. A provisional instrument for this purpose includes a positioning tray having a peripheral profile corresponding to that of the tibial platform of the prosthesis, the tray having an upper surface and an under surface which is substantially flat and free from projections and the tray having a plurality of holes for receiving pins for temporarily attaching the positioning tray in a desired position on the resected tibial surface. Also disclosed is a jig for guiding, drilling and broaching operations, the jig having an aperture which is shaped to guide the broach.

Abstract: A prosthetic joint for replacing a natural joint in a body includes a first prosthetic component of the prosthetic joint which, when implanted into a first resected bone of the natural joint has a junction between the implanted component and the bone. The joint further includes a second prosthetic component of the prosthetic joint which, when implanted into an adjacent resected bone of the natural joint, articulates with the first component. A microporous membrane surrounds the first prosthetic component and is secured to the first prosthetic component and, when implanted in a body, is secured to bone surrounding said first prosthetic component, thereby sealing the junction against ingress of particles, but permitting liquids to pass through said membrane without restricting articulation of the joint.

Abstract: A prosthesis for total knee replacement (TKR) includes: a femoral component having a pair of condylar-bearing surfaces (10,12), a tibial component having a tibial platform (22) with an upstanding abutment (18) located between the condylar-bearing surfaces, and a meniscal component (15) interposed between the condylar-bearing surface and the tibial platform for sliding movement in the anterior-posterior (A-P) direction. The femoral component has an intercondylar projecting surface (20) adapted to contact the upstanding abutment at high degrees of flexion so as to influence the sliding movement of the meniscal component in a posterior direction.

Abstract: A condylar replacement knee prosthesis has a tibial platform adapted for attachment to a resected tibia, a femoral component adapted for attachment to a resected femur and a plastics meniscal component interposed between the femoral and tibial components. The upper surface of the meniscal component is shaped to correspond with bearing surfaces of the femoral component. The meniscal component is guided for sliding movement in an anterior-posterior direction on the tibial component and for limited rotational movement, the rotational movement being centred about an axis which is displaced medially from the anterior-posterior centre line of the tibial component.

Abstract: A method of fitting orthopaedic prostheses is disclosed in which a semi-permeable microporous membrane is fitted over an implanted prosthesis so as to cover the junction between the prosthesis and the bone. In this way, particles generated by mechanical wear of the prosthesis are excluded. Such particles are believed to inhibit bone regeneration in the region of the prosthesis. In addition, by preventing the ingress of fibrous connective tissue cells, a secondary seal of new bone will form between the membrane and the original bone.

Abstract: A femoral prosthesis is disclosed comprising a bicondylar femoral component (41), a tibial component (72) and at least one meniscal component (42) interposed between the femoral and tibial components, the femoral component including a pair of condylar surfaces (46) separated by a patella bearing surface (44) which in use provides a normal anatomical patella lever arm, the condylar surfaces being shaped for substantial conformity with corresponding tibial bearing surfaces (47) of the meniscal component or components over the entire range of normal flexion.