An external fixation strut (200, 200', 200", 200"'), comprising: an elongated body comprising at least a first shaft and a second shaft moveable with respect to each other to modify the length of said elongated body; at least a sensor (214, 214', 214") integrated in the external fixation strut (200, 200', 200", 200"') and adapted to perform at least a measurement which is indicative of the length of the elongated body; wherein said sensor (214, 214', 214") is configured to use either an inductive or a capacitive technology to determine the position of a movable element; characterized in that said sensor (214, 214', 214") is configured to communicate with a programmable tool for lengthening/shortening the external fixation strut (200, 200', 200", 200"') through a data port which is engageable by said programmable tool; wherein said movable element is an end-piece of the second shaft and/or a metering cursor (219, 219') which is configured to translate with said end-piece with respect to the second shaft; wherein said end-piece is slidable within a tubular body of the first shaft; wherein the sensor comprises a sensing strip arranged within the tubular body of the first shaft; wherein said sensing strip is a flexible printed circuit board and it is attached on top of a rigid support plate; wherein said rigid support plate is made of ferromagnetic material and at least partly shields the sensing strip from external noise; wherein a longitudinal slit is provided at least internally along the tubular body of the first shaft, so that the sensing strip and the rigid support plate can be inserted through said longitudinal slit in a mounting phase. an elongated body comprising at least a first shaft and a second shaft moveable with respect to each other to modify the length of said elongated body; at least a sensor (214, 214', 214") integrated in the external fixation strut (200, 200', 200", 200"') and adapted to perform at least a measurement which is indicative of the length of the elongated body; wherein said sensor (214, 214', 214") is configured to use either an inductive or a capacitive technology to determine the position of a movable element; characterized in that said sensor (214, 214', 214") is configured to communicate with a programmable tool for lengthening/shortening the external fixation strut (200, 200', 200", 200"') through a data port which is engageable by said programmable tool; wherein said movable element is an end-piece of the second shaft and/or a metering cursor (219, 219') which is configured to translate with said end-piece with respect to the second shaft; wherein said end-piece is slidable within a tubular body of the first shaft; wherein the sensor comprises a sensing strip arranged within the tubular body of the first shaft; wherein said sensing strip is a flexible printed circuit board and it is attached on top of a rigid support plate; wherein said rigid support plate is made of ferromagnetic material and at least partly shields the sensing strip from external noise; wherein a longitudinal slit is provided at least internally along the tubular body of the first shaft, so that the sensing strip and the rigid support plate can be inserted through said longitudinal slit in a mounting phase.