A bone screw for sacroiliac joint fusion is characterized by a longitudinal bone screw and a cylindrical sleeve received on a proximal end of the bone screw. The sleeve has axially extending fins or flutes on its outer surface that extend generally from one end of the sleeve to the other end of the sleeve. This feature allows the sleeve to resist reverse rotation which, in turn, aids in preventing back-out of the bone screw once installed. The bone screw has a self-tapping tip that allows the bone screw to be installed without need for a pilot hole, and self-harvesting geometry that gathers and retains bone shavings in and along the bone screw that are produced by bone screw installation for use as graft for bone fusion.