A spacer for separating bones of a joint includes a frame and a carriage. The carriage has ramped surfaces, and is slideably moveable in relation to the frame. A screw support is moveably connected to the frame to form a changeable angular orientation with respect to the frame. An actuating screw is supported by the screw support, and is connected to the carriage to cause the carriage to slideably move in relation to the frame when the actuating screw is rotated. Opposing endplates are configured to engage opposing bone of the joint, and each has ramped surfaces mateable with the ramped surfaces of the carriage. When the carriage is moved by rotation of the actuating screw, the ramped surfaces of the carriage and the endplates slide against each other, causing the endplates to move relatively apart, to increase the height of the spacer.