Importance

Loading Importance Indicators...

Abstract

Joint endoprosthesis for the total replacement of degenerate joints such as the ankle, knee, elbow, wrist and finger. When embodied as an ankle endoprosthesis (10), the device comprises a tibial component (11) for being secured to the tibia and which provides a first bearing surface (21a); a talar component (13) for being secured to the talus anhd which provides a second bearing surface (34) which is at least a segment of a surface of revolution about a first axis; and a tibial insert (12) intermediate the tibial and talar components (11 and 13) which provides a third bearing surface (26a) which provides area contact with the first bearing surface (21a) and which is engageable therewith to permit relative rotation between the tibial component (11) with respect to the tibial insert (12) and the talar component (13) about a second axis which is not parallel to the first axis and is substantially parallel to the shaft of the tibia and which relative rotation provides one of only two degrees of freedom of rotational movement of said tibia with respect to said talus, and wherein the tibial insert (12) is further provided with a fourth bearing surface (29) in area contact with the second bearing surface (34) which is no more than one-half a complete surface of revolution and for area contact sliding engagement therewith to permit relative rotational movement of the tibial component (11) and tibial insert (12) with respect to the talar component (13) about the first axis which relative rotation thereby provides the second of only two degrees of freedom of rotational movement of said tibia with respect to said talus so long as these bearing surfaces are kept in area contact but allowing a third rotational motion by partial separation of these surfaces.

Loading the Abstract Image...

First Claim