A bone joint spacer has two endplates which have a bone engaging surface on one side, and ramps extending from an opposite side. A shaft has a threaded end, and another end which has ramp followers which mate with the endplate ramps of both endplates. A collar slides over the threaded end of the shaft, and also has ramp followers which mate with the endplate ramps of both endplates. A nut threads onto the end of the shaft and pushes the collar towards the ramp followers of the shaft. This movement causes the ramp followers to slide the ramp followers of the collar and the shaft against the endplate ramps, pushing the endplates apart. Two of these spacers can be combined by a link plate so that the spacers can be aligned or curved into a U-shape to be inserted into the body and positioned between bony surfaces, respectively.