An implant comprising: a first endplate configured to engage a first vertebral body and having at least one ramped surface on a side opposite a bone engaging side; a second endplate configured to engage a second vertebral body and having at least one ramped surface on a side opposite a bone engaging side of the first hinged portion; a frame coupled to the first and second endplates (110C;112C) to enable the first and second endplates (110C;112C) to move relative to each other with respect to the longitudinal axis, in connection with the frame; an actuator screw rotatably coupled to the frame; and a carriage coupled to the actuator screw, whereby rotation of the actuator screw moves the carriage with respect to the frame and the first and second endplates (110C;112C); wherein the carriage comprises a plurality of ramps (168;168A;170;170A) each mateable with at least one of the at least one ramped surfaces of the first and second endplates(110C;112C), wherein when the carriage is moved by rotation of the actuator screw, at least one of the at least one ramped surface of the first endplate and at least one of the at least one ramped surface of the second endplate each translate along at least one of the plurality of ramps (168;168A;170;170A) of the carriage to cause the endplates to move relative to each other in connection with the frame, characterised in that the implant further comprises at least one radiopaque marker positioned in connection with at least one of the first and second endplates (110C;112C), whereby an extent of movement of the connected endplate can be determined using imaging by a relative alignment of the radiopaque marker and a radiopaque element of the implant which does not move together with the connected endplate. a first endplate configured to engage a first vertebral body and having at least one ramped surface on a side opposite a bone engaging side; a second endplate configured to engage a second vertebral body and having at least one ramped surface on a side opposite a bone engaging side of the first hinged portion; a frame coupled to the first and second endplates (110C;112C) to enable the first and second endplates (110C;112C) to move relative to each other with respect to the longitudinal axis, in connection with the frame; an actuator screw rotatably coupled to the frame; and a carriage coupled to the actuator screw, whereby rotation of the actuator screw moves the carriage with respect to the frame and the first and second endplates (110C;112C); wherein the carriage comprises a plurality of ramps (168;168A;170;170A) each mateable with at least one of the at least one ramped surfaces of the first and second endplates(110C;112C), wherein when the carriage is moved by rotation of the actuator screw, at least one of the at least one ramped surface of the first endplate and at least one of the at least one ramped surface of the second endplate each translate along at least one of the plurality of ramps (168;168A;170;170A) of the carriage to cause the endplates to move relative to each other in connection with the frame, characterised in that the implant further comprises at least one radiopaque marker positioned in connection with at least one of the first and second endplates (110C;112C), whereby an extent of movement of the connected endplate can be determined using imaging by a relative alignment of the radiopaque marker and a radiopaque element of the implant which does not move together with the connected endplate.