Abstract: 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 to the disclosed method, the bone staple is implanted by driving the staple partly into two bone members and then rotating the body to threadably adjust the positions of the arms and thereby exert a force between the bone members. The staple is next driven further by striking the striking surface until the protrusion embeds beneath a bone surface to prevent rotation of the body. A driver tool useful for implanting the staple has a clamping head which receives the staple body and rigidly clamps the angled arms.