Other

University College London

Zimmer Gmbh

Peter Stanley Walker

John N Insall

Gordon William Blunn

Jonathan Blamey

David Barrett

William Muirhead-Allwood

Michael Wadcock

Mark Alan Heldreth

Steven A Zawadzki

Shawn Elliott McGinley

A condylar total knee replacement prosthesis is disclosed having interacting guide surfaces for control of anterior-posterior displacement. The prosthesis comprises a femoral component (,) having a pair of condylar surfaces (,), a tibial component having a tibial platform (,) and a bearing component interposed between the femoral and tibial components. A femoral guide surface (,) is located between the condyles and engages with a tibial guide surface (,) 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.

Knee prosthesis having guide surfaces for control of anterior-posterior displacement

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). To install the prosthesis, a femur (1) is resected to provide a base for receiving the femoral component (2), which is retained in the resected femur by pins (3). The tibia (4) is resected to provide a flat base into which the tibial component (6) is fixed by a stem (5).

Prosthesis for knee replacement

Total knee replacement prosthesis

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. In addition, the invention includes a tibial broach which includes a hollow body having an upper end and a lower end and having an anvil at its upper end, an interior face and a posterior face which slopes downwardly towards a lower end, the posterior face having a series of teeth which are formed in the hollow body, such that bone cut by the teeth as the broach is driven into an intramedullary canal of a tibia passes into the hollow body.

Evaluating the fit of an orthopaedic implant

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.

Bone implants

Stabilised mobile bearing knee

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.

Prostheses for knee replacement

Method of sealing an interface between an articulating prosthesis and

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.

Growing community of inventors

Middlesex, United Kingdom

Peter Stanley Walker