A graft cage includes cross-sectional portions and longitudinal members. Each portion includes base transverse members forming a cage base; a first arm including first arm transverse members; a second arm including second arm transverse members; base connecting struts, each base connecting strut extending between first one and second one of the base members; first arm connecting struts, each first arm connecting strut extending between a first one of the first members and a second one of the first members; and second arm connecting struts, each second arm connecting strut extending between first one and second one of the second members. The longitudinal members connect the portions to one another. Intersections of the portions with the longitudinal members forming pores in the first and second arms. The pores receive an arm tip of a further graft cage therein to interlock the cage with the further cage.