A method of manufacturing a composite interbody device includes assembling superior and inferior endplates, this including forming or layering micro-porous titanium on opposing sides of a solid titanium sheet. A first of the opposing sides provides a micro-porous bone interface layer and a second of the opposing sides provides a micro-porous core interface side. The solid titanium sheet therebetween forms a central barrier layer. The inferior and superior endplates are placed in a mold, on each side of a core cavity, with the core interface sides facing the core cavity and the bone interface sides facing away from the cavity. Molten plastic is injection-molded into the core cavity to form a plastic core between the endplates, the molten plastic extruding into pores of the microporous core interface sides. The plastic is set to bond the core with the endplates.
