An external fixation system comprising: first and second planar at least part-circular ring elements, the first ring element having a circumferential track extending along the part-circular circumference thereof; a plurality of struts each having a first and second end, the first end of each strut coupled to the first ring by a first connector and the second end of each strut coupled to a second ring by a second connector, the first connector including a spherical joint; the second connector non-rotatably coupled to the second ring, the strut second end being coupled to the second connector by a U-joint; shuttles mounted on the track of the first ring for movement there along with one shuttle coupled to each strut; and means for controlling the angular position of each strut second end and means for controlling the position of each shuttle along the circumferential track on the first ring.