Abstract: An apparatus used in the treatment of spinal fractures and scoliosis. A threaded rod carries 2 or more sleeves, each sleeve surrounding a portion of the rod and slideable along the entire length of the rod. Each sleeve engages a hook to interconnect the rod with the hook. The hook includes a base for engaging the sleeve. The base has a bore therethrough which receives the sleeve, and a slot is located parallel to and communicating with the bore. The slot has a width which is greater than the diameter of the rod and less than the outside diameter of the sleeve so that the rod can be placed into the slotted base of the hook and held in position by the sleeve which is slipped over the rod and into the bore. A projecting hook portion is integrally connected with the base and is used to engage the bone of the spinal column. A locking system in the form of threaded nuts engages the rod securing the position of the sleeve so that the entire hook assembly may be held in place with respect to the rod.