a stem of the joint endoprosthesis;

a sleeve having a top and a bottom, a distance between said top and said bottom defining an entire height of said sleeve, wherein the sleeve surrounds a channel extending through the sleeve from the top to the bottom of the sleeve wherein the channel is configured to receive the stem of the joint endoprosthesis, wherein the channel is configured so the stem extends past both the top of the sleeve and the bottom of the sleeve;

the sleeve comprising an inner face and an outer face, the inner face defining the channel, and a distance between the inner face and the outer face defining a thickness;

the sleeve further comprising a porous material configured for ingrowth of bony material, wherein the porous material is on the outer face of the sleeve;

a top cover, wherein the top cover covers a top surface of the top of the sleeve and leaves the channel open, wherein the sleeve comprises at least one recess on the top of the sleeve, wherein the top cover and the recess are connected such as to provide a continuous top bulkhead extending completely around a circumference of the channel, and wherein the at least one recess is configured to receive a portion of the joint endoprosthesis; and

a void configured for compression of the channel,

wherein the sleeve is compressible in at least one of a media-lateral direction and an anterior/posterior direction, and

wherein the bottom is stepped, and wherein a first portion of the bottom comprises a reduced height as compared to a second portion of the bottom and a transition surface connects the first portion to the second portion.