An implantable medical device, comprising: a body including an external surface defining an outer profile of said device, said body further including: a porous matrix including a series of interconnected macropores defined by a plurality of interconnected struts; and a filler material substantially filling at least a portion of said series of interconnected macropores; the struts being hollow, with each strut including a hollow interior, wherein said hollow interiors of said plurality of interconnected struts are interconnected and in communication with one another, thereby forming a hollow matrix of passages that extends through the struts; and a plurality of openings extending through at least a portion of said external surface and communicating with said hollow interior of at least a portion of said plurality of interconnected struts to thereby expose corresponding passages, the opening providing an access point for bone and/or tissue to grow into passage of the corresponding strut, wherein bone and/or tissue growth into one passage can spread into additional passages since the passages are interconnected; wherein said porous matrix comprises a ceramic material and said filler material comprises a polymeric material; wherein said ceramic material is bioresorbable and said polymeric material is biologically stable; wherein said ceramic material comprises a calcium-based ceramic; and wherein said polymeric material is selected from the group consisting of polyetheretherketone (PEEK), carbon-reinforced PEEK, and polyetherketoneketone (PEKK). a body including an external surface defining an outer profile of said device, said body further including: a porous matrix including a series of interconnected macropores defined by a plurality of interconnected struts; and a filler material substantially filling at least a portion of said series of interconnected macropores; the struts being hollow, with each strut including a hollow interior, wherein said hollow interiors of said plurality of interconnected struts are interconnected and in communication with one another, thereby forming a hollow matrix of passages that extends through the struts; and a plurality of openings extending through at least a portion of said external surface and communicating with said hollow interior of at least a portion of said plurality of interconnected struts to thereby expose corresponding passages, the opening providing an access point for bone and/or tissue to grow into passage of the corresponding strut, wherein bone and/or tissue growth into one passage can spread into additional passages since the passages are interconnected; wherein said porous matrix comprises a ceramic material and said filler material comprises a polymeric material; wherein said ceramic material is bioresorbable and said polymeric material is biologically stable; wherein said ceramic material comprises a calcium-based ceramic; and wherein said polymeric material is selected from the group consisting of polyetheretherketone (PEEK), carbon-reinforced PEEK, and polyetherketoneketone (PEKK). a porous matrix including a series of interconnected macropores defined by a plurality of interconnected struts; and a filler material substantially filling at least a portion of said series of interconnected macropores; the struts being hollow, with each strut including a hollow interior, wherein said hollow interiors of said plurality of interconnected struts are interconnected and in communication with one another, thereby forming a hollow matrix of passages that extends through the struts; and a plurality of openings extending through at least a portion of said external surface and communicating with said hollow interior of at least a portion of said plurality of interconnected struts to thereby expose corresponding passages, the opening providing an access point for bone and/or tissue to grow into passage of the corresponding strut, wherein bone and/or tissue growth into one passage can spread into additional passages since the passages are interconnected; wherein said porous matrix comprises a ceramic material and said filler material comprises a polymeric material; wherein said ceramic material is bioresorbable and said polymeric material is biologically stable; wherein said ceramic material comprises a calcium-based ceramic; and wherein said polymeric material is selected from the group consisting of polyetheretherketone (PEEK), carbon-reinforced PEEK, and polyetherketoneketone (PEKK).