A method and apparatus for use in the treatment of spinal fractures and scoliosis. Windowed hook holders are used to firmly grasp and position hooks having a slotted base and a projecting hook on the spinal column. The projecting hook is used to engage the bone of the spinal column.Two or more hooks are held firmly in place on the spinal column with the hook holders. A threaded rod carrying two or more sleeves which are slideable along the length of the rod and locking nuts are aligned with the hooks and the sleeves and nuts spaced along the rod to correspond approximately to the spacing of the positioned hooks.The threaded rod, sleeves and nuts are then passed through the window openings of the hook holders and aligned with the hooks without disengaging the hook holders from the hooks. The threaded rod is then dropped into the slots and the sleeve slid into the hook base to hold the rod in the hook. Opposing openings are located on either side of the base for engagement by the hook holder, to aid in the placement of the hook and to hold the hook before and during interconnection with the threaded rod. Preferably, the hook assembly forms a part of a Harrington compression rod or a tensioning means which interconnects a Harrington distraction rod and a Harrington compression rod. Adjustment of the locking nut locks the hook to the rod.