The invention includes a synthetic bone substitute material suitable for use as a replacement for cancellous bone in a bone graft composition, the material comprising a reticulated framework of interconnecting bioceramic struts defining an interconnecting interstitial void volume, and a solid non-porous composition substantially filling the interstitial void volume and in intimate contact with the reticulated framework, the pore-filling composition comprising calcium sulfate. Calcium triphosphate is a preferred bioceramic material for the reticulated framework.