A two-component system for joining two bones or bone fragments, in which a first component is threaded, self-tapping and bears an annular mating end to engage two mating pins on the end of a second component which is also threaded and self-tapping. The two components have opposite handed threads thereon, so that upon final installation into adjacent bone the final rotation brings the abutted bone surfaces into a compressive engagement as each components burrows deeper into its respective bone surface.
