Abstract: A bone-setting assembly essentially comprised of a pair of tubular members adapted to be inserted in the intramedullary passages of the respective parts of a broken bone, and a central connecting and aligning pin that is arranged to be slidably received in the interior passages of the tubular members. The tubular members are driven into position in the bone passages and a portion of the exterior surface of each member is roughened to firmly fix the member in the bone. The interior passages of the tubular members are preferably square in cross section and the central pin has a conforming square cross section so that there can be no relative rotation between the tubular members and thus between the parts of the broken bone. The central pin is threaded over approximately half of its length and a nut is threaded on this portion of the pin.