An orthopaedic reference gantry for planning and implementation of orthopaedic procedures has a base platform (100, figure 1) to which is releasably attached a reference gantry kinematic loop 300. A reference gantry arm 250 for receiving and adjusting the orientation and position of a plurality of instruments is mounted on the loop. Instruments are connected or applied to one or more bone segments. The reference gantry defines a Cartesian coordinate system for defining the orientation and position of the instruments and/or the one or more bone segments placed in the coordinate system. The base platform may have a radiolucent reference grid with cutaway channels to receive additional (vertical) reference grids (25, figure 8) or clamp assemblies (60, figure 3). The kinematic loop may comprise two vertical guide rails 180 connected by a horizontal stage 210 bearing a vertical stage 230 on which is mounted the gantry arm.
