According to one aspect of the present invention, there is provided a tibial component (10), suitable for use in an orthopedic prosthesis, which prosthesis includes a femoral component and a spacer bearing (70), the tibial component comprising a planar tibial plate (15) having an upper bearing surface (30) and a lower attachment surface (20), and the tibial plate further having at least one spacer bearing attachment means for removably securing the spacer bearing to the tibial plate.