The invention relates to a plug-on module (1) for pushing onto a free end of a shaft (6) formed for implantation in a long bone (7), comprising a holding body (2) with an axial bore (20) for the shaft (6) at its lower end and a joint head (3) as part of a joint endoprosthesis, wherein the joint head (3) is offset downwards in the axial direction (26) from the upper end of the holding body (2) sufficiently far and in such a way that the shaft (6) protrudes upwards beyond the joint head (3). With such a quasi-offset arrangement the range of usage for the plug-in module is extended to cases in which previously a shorter through-going shaft would have been required and therefore a troublesome adjustment operation to exchange the through-going shaft would have to have been carried out.
