Tibial element for a replacement knee prosthesis
AssigneeHowmedica International Inc.
InventorsAlan Ashby, Paul F. Dorrell
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Abstract
A tibial element is provided for a replacement knee prosthesis which comprises a tibial tray provided with a bearing component having medial and lateral compartments. Control means acting between the tray and the bearing component are included which provide free posterior and anterior movement of the lateral compartment which is greater than any allowed free posterior and anterior movement of the medial compartment in relation to the tray. Thus, there is no relative free posterior movement and anterior movement of the medial compartment or some may be allowed.
Claims14
A tibial element for a replacement knee prosthesis comprising a tibial tray having an upper surface provided with a bearing component having medial and lateral compartments, and including control means acting between said tray and said bearing component which provides free posterior and anterior movement of the bearing lateral compartment which is greater than any allowed free posterior and anterior movement of the bearing medial compartment in relation to the tray, said control means including a curved track in the base of the bearing component and a guide in the form of a projecting boss located within said track and carried on said tray, said guide provided by part of a fastener which acts to secure an attachment element to the lower part of the tray.
A tibial element for a replacement knee prosthesis comprising:
- a tibial tray having a first boss extending from an upper surface thereof and a boss extending upwardly from said upper surface located posteriorly of said first boss, said bosses having generally the same cross-sectional dimensions, said first boss having a flanged upper end;
- a bearing component having a lower surface for engaging the upper surface of said tray, said lower surface having a curved track in the form of an open slot extending in the anterior-posterior direction, an internal flange in the form of a groove formed around the edges of said slot for receiving the flange of said first boss, said slot having a width generally corresponding to the cross-sectional dimension of said bosses, said groove having an anterior end recessed further from said lower surface than a posterior end of said groove, said groove having an enlarged opening between said anterior and posterior ends thereof for receiving said flanged upper end of said first boss allowing said flange to move from said posterior end of said groove into said recessed anterior end of said groove.
Dependencies are inferred from the claim text.