A spacer for separating bones of a joint, the spacer includes a first endplate configured to engage a first bone of the joint, and comprising a ramped surface; a tissue engaging subassembly disposed in a compartment of the first endplate; a second endplate configured to engage a second bone of the joint; and a frame subassembly that extends between the first endplate and the second endplate. The frame subassembly comprises a drive nut, a drive shaft coupled to the drive nut, a ramped carriage coupled to the drive shaft, wherein the ramped carriage comprises a ramped surface operable to engage the ramped surface of the first endplate, and an actuation bar coupled to the drive nut comprising a plate operable to engage the tissue engaging subassembly.