Modular trial tibial insert

Abstract

A modular tibial trial prosthesis for attachment to a patient's surgically cut proximal tibia includes a tibial tray having proximal and distal surfaces, the distal surface to be fitted against the patient's surgically prepared proximal tibia during knee joint replacement surgery. The proximal surface of the tray accepts any one of a plurality of plastic liner inserts that fits the tray at the proximal tray surface with an interlocking connection. The liner inserts each have a distal surface for attachment to the tray and a proximal articulating surface that is receptive of a distal femoral articulating surface. The proximal articulating surface has concavely-shaped portions. The concavely-shaped portions of the liner inserts provide different articular geometries for selection by the user. A plurality of spacers of different thicknesses can be positioned in between a selected one of the plastic liner inserts and the tibial tray. Each spacer has proximal and distal surfaces. The spacers have connecting portions on each of said proximal and distal surfaces for forming respective connections with a tibial tray and a selected plastic liner insert. The liner inserts each have connecting portion on the distal surface thereof for connecting to the proximal surface of the spacer and to the proximal surface of the tray. The liner inserts and spacers each have a periphery in the form of a sidewall that extends generally perpendicular to the proximal surface of the patient's transversely cut proximal tibia. The periphery of the insert and spacers are of corresponding shape.