Abstract: A tibial tray with a proximal surface, the proximal surface comprising at least two, in particular exactly two central fixation elements for enabling a connection with a tibial insert as a further part of an artificial knee joint, wherein the at least two central fixation elements are protrusions from the proximal surface in the proximal direction and the at least two central fixation elements are positioned symmetrically and/or parallel to a medial plane of the proximal surface, the medial plane being perpendicular to the proximal surface and intersecting the proximal surface in the middle between two most lateral points of the proximal surface.

Abstract: The invention relates to a method for checking ceramic ball heads (3) for hip-joint prostheses which have a receiving space (8) with a conical side face with a clamping cone angle ? and a cone inlet (7) and are subjected to a pressure in order to check areas of the receiving space (8). To ensure that all the checked ball heads (3) also remain functionally ready for relevant, oblique in vivo load situations without suffering damage, it is proposed that only the area of the cone inlet (7) is subjected to a radial force perpendicular to the longitudinal axis of the ball head (3).

Abstract: The invention relates to a method for checking ceramic ball heads (3) for hip-joint prostheses which have a receiving space (8) with a conical side face with a clamping cone angle ? and a cone inlet (7) and are subjected to a pressure in order to check areas of the receiving space (8). To ensure that all the checked ball heads (3) also remain functionally ready for relevant, oblique in vivo load situations without suffering damage, it is proposed that only the area of the cone inlet (7) is subjected to a radial force perpendicular to the longitudinal axis of the ball head (3).