The natural oils in Bone can make it difficult to get strong bond even with good CA glue. Prepping the surface is key. Wiping with a solvent can work, but needs to be done thoroughly or it only wicks more oil to the surface.
I wipe the surface of the bone down with vinegar. Vinegar or other acid works well to degrease the bone. Then glued with loctite pro. This has been the only thing that works consistently for me.