The invention relates to an augment device for a joint endoprosthesis, in particular a tibial augment for a knee joint endoprosthesis, comprising a sleeve (10) surrounding a channel (11) extending through the sleeve (10). The sleeve (10) is formed of porous material (2) for ingrowth of bony material, the sleeve (10) comprising an inner face (14) and an outer face (15). The sleeve (10) further comprises a wall (3) surrounding the channel (11), the wall (3) being made of solid material and forming a sandwich structure with the porous material (2), wherein the wall (3) forms a bulkhead between the inner face (14) and the outer face (15). Thereby, the bulkhead wall (3) will stop inflow of any cement across the sleeve (10) from its inner (14) to its outer face (15). The porous material (3) on the outer face (15) will be kept free from cement and its capability to promote bone ingrowth is reliably preserved. The augment devices are preferably provided as a set having different sizes and straight or stepped bottoms for improved versatility and maximum preservation of natural bone matter.La invención se refiere a un dispositivo de aumento para una endoprótesis articular, en particular un aumento tibial para una endoprótesis articular de rodilla, comprendiendo una funda (10) que rodea un canal (11) que se extiende a través de la funda (10). La funda (10) se forma de material poroso (2) para el crecimiento interno de material óseo, la funda (10) comprendiendo un lado interior (14) y un lado exterior (15). La funda (10) comprende además una pared (3) que rodea el canal (11), la pared (3) haciéndose de material sólido y formando una estructura de emparedado con el material poroso (2), en donde la pared (3) forma un tabique entre el lado interior (14) y el lado exterior (15). Así, la pared del tabique (3) detendrá la entrada de cualquier pegamento a través de la funda (10) desde su lado interior (14) a su lado exterior (15). El material poroso (3) en el lado exterior (15) se man
