An orthopaedic device having a first fixator ring and a second fixator ring coupled via at least three adjustable spacing elements , wherein each of the first and the second fixator rings is made of material at least partially permeable for X-radiation and has means for connecting adjustable spacing elements , has a marker located inside the ring and made of a material visible in images made by means of X-radiation, having a form of arc segment , made of a material of lower X-radiation transmission factor than an average transmission factor of the fixator ring material and has means for connecting the adjustable spacing elements , each of the at least three adjustable spacing elements has a tube and an externally threaded rod having a first end coupled to the first fixator ring and a second end that protrudes to the first end of the tube and is movable inside the tube, wherein the tube has second end coupled to the second fixator ring , wherein each of the at least three adjustable spacing elements is provided with a first rotation compensating joint for connecting the externally threaded rod to the first fixator ring and a second rotation compensating joint for connecting the tube with the second fixator ring , wherein the first and the second rotation compensation joints are fixedly connected to the first and the second fixator rings , respectively the first end of the tube is cleft and the tube has an internally threaded portion which at the cleft of the tube has an internal thread compatible with the thread of the externally threaded rod , a longitudinal slit , and machine readable scale provided on its outer surface, each tube further having a position reading device movably attached thereto, wherein the position reading devices have a power supply, a processing unit with memory, communication means and a scale reader unit for reading the machine readable scale of the tube, and are coupled with the second end of the respective externally threaded rods via the longitudinal slits . has a marker located inside the ring and made of a material visible in images made by means of X-radiation, having a form of arc segment , made of a material of lower X-radiation transmission factor than an average transmission factor of the fixator ring material and has means for connecting the adjustable spacing elements , each of the at least three adjustable spacing elements has a tube and an externally threaded rod having a first end coupled to the first fixator ring and a second end that protrudes to the first end of the tube and is movable inside the tube, wherein the tube has second end coupled to the second fixator ring , wherein each of the at least three adjustable spacing elements is provided with a first rotation compensating joint for connecting the externally threaded rod to the first fixator ring and a second rotation compensating joint for connecting the tube with the second fixator ring , wherein a first rotation compensating joint for connecting the externally threaded rod to the first fixator ring and a second rotation compensating joint for connecting the tube with the second fixator ring , wherein the first and the second rotation compensation joints are fixedly connected to the first and the second fixator rings , respectively the first end of the tube is cleft and the tube has an internally threaded portion which at the cleft of the tube has an internal thread compatible with the thread of the externally threaded rod , a longitudinal slit , and machine readable scale provided on its outer surface, each tube further having a position reading device movably attached thereto, wherein the position reading devices have a power supply, a processing unit with memory, communication means and a scale reader unit for reading the machine readable scale of the tube, and are coupled with the second end of the respective externally threaded rods via the longitudinal slits . <EOS>