A robotic system comprising: an end effector (6, 180) having a jaw (18, 20, 50, 70, 194) and a moveable element (24, 84, 185, 195) which is a cutting blade, a user interface display; a drive (184, 210) comprising a motor; a mechanism (192, 240) operatively coupling the drive (184, 210) to the moveable element (24, 84, 185, 195); a processor configured to: determine a displacement of the drive (184, 210) or the mechanism (192, 240); track a kinematic chain of the moveable element (24, 84, 185, 195); determine a position of the moveable element (24, 84, 185, 195) relative to the end effector (6, 180) using the tracking of the kinematic chain of the moveable element (24, 84, 185, 195) and the displacement of the drive (184, 210) or the mechanism (192, 240), the position of the moveable element (24, 84, 185, 195) relative to the end effector (6, 180) being determined from among a pre-cut position, a cut-complete position, and any position between the pre-cut position and the cut-complete position; display, on the user interface display, a visual indicator of the position of the moveable element (24, 84, 185, 195) relative to the end effector (6, 180) when the moveable element (24, 84, 185, 195) is obscured by the end effector (6, 180); and said processor being characterized in that it is further configured to display, on the user interface display, a video image of an environment of the moveable element. an end effector (6, 180) having a jaw (18, 20, 50, 70, 194) and a moveable element (24, 84, 185, 195) which is a cutting blade, a user interface display; a drive (184, 210) comprising a motor; a mechanism (192, 240) operatively coupling the drive (184, 210) to the moveable element (24, 84, 185, 195); a processor configured to: determine a displacement of the drive (184, 210) or the mechanism (192, 240); track a kinematic chain of the moveable element (24, 84, 185, 195); determine a position of the moveable element (24, 84, 185, 195) relative to the end effector (6, 180) using the tracking of the kinematic chain of the moveable element (24, 84, 185, 195) and the displacement of the drive (184, 210) or the mechanism (192, 240), the position of the moveable element (24, 84, 185, 195) relative to the end effector (6, 180) being determined from among a pre-cut position, a cut-complete position, and any position between the pre-cut position and the cut-complete position; display, on the user interface display, a visual indicator of the position of the moveable element (24, 84, 185, 195) relative to the end effector (6, 180) when the moveable element (24, 84, 185, 195) is obscured by the end effector (6, 180); and said processor being characterized in that it is further configured to display, on the user interface display, a video image of an environment of the determine a displacement of the drive (184, 210) or the mechanism (192, 240); track a kinematic chain of the moveable element (24, 84, 185, 195); determine a position of the moveable element (24, 84, 185, 195) relative to the end effector (6, 180) using the tracking of the kinematic chain of the moveable element (24, 84, 185, 195) and the displacement of the drive (184, 210) or the mechanism (192, 240), the position of the moveable element (24, 84, 185, 195) relative to the end effector (6, 180) being determined from among a pre-cut position, a cut-complete position, and any position between the pre-cut position and the cut-complete position; display, on the user interface display, a visual indicator of the position of the moveable element (24, 84, 185, 195) relative to the end effector (6, 180) when the moveable element (24, 84, 185, 195) is obscured by the end effector (6, 180); and said processor being characterized in that it is further configured to display, on the user interface display, a video image of an environment of the moveable element.