A bone replacement filler comprising a biomedical ceramic particulate, wherein the filler is able to flow without the application of an external shear stress or compressive force or under a relatively low shear stress or compressive force, but resists flow or does not flow when subjected to a higher shear stress or compressive force, and wherein at least some of the particles in the ceramic particulate have a micro-porous surface structure and/or a micro-porous sub-surface structure.