A bone staple includes a body and a pair of angled arms oppositely threaded into opposite ends of the body. The body has at least one generally flat periphery striking surface and a corresponding relatively sharp outward protrusion at an opposite side of the body from the striking surface. According...http://www.google.de/patents/US4723540?utm_source=gb-gplus-sharePatent US4723540 - Apparatus and method for exerting and maintaining a force between two bone members
