A spacer for separating bones of a joint, the spacer includes a first endplate configured to engage a first bone of the joint； a second endplate configured to engage a second bone of the joint； and an actuation subassembly comprising a drive nut, a drive screw coupled to the drive nut, and a cam frame coupled to the drive screw, wherein the cam frame is disposed between the first endplate and the second endplate, wherein the cam frame comprises a proximal frame end, a distal frame end, and lateral frame sides, wherein cams disposed on the lateral frame sides selectively engage at least one of the first endplate or the second endplate.
