An endplate for an intervertebral prosthesis includes a generally planar base plate, a first elevated region, or dome, within the base plate periphery, and a second elevated region, or dome, within the boundary of the first elevated region. The antero-posterior and side-to-side (medial-lateral) dimensions of the first elevated region are made to be unequal in order to provide resistance to torsional stresses, and the laterally opposite sidewalls of the first elevated region are defined by arcs that terminate in sagittal planes of the endplate, and are symmetrical with respect to a coronal plane of the endplate. A bone rasp and a groove cutter for use in implanting the prosthesis are also provided.