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 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 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. <EOS>