A fusion cage may include an upper endplate directly hinged to a lower endplate. The fusion cage may be adjustable to provide various angles between the endplates. An insert may be coupled between the endplates to lock the endplates at a selected angle. Fasteners may extend through the fusion cage into adjacent bone portions. An instrument may couple to an endplate so that the hinged-together endplates may be inserted between bone portions. The instrument may be used to adjust the angle between the endplates and to couple the insert between the endplates.