Abstract: A mechanism for aligning a hypodermic needle or other probe with a predetermined location within a patient has a radio-transparent guide with a lengthwise slot for accommodating the needle. A pair of radiopaque rings spaced at opposite ends of the guide enables the surgeon to align the needle with the predetermined location and advance the needle in a continuous and steady movement toward the predetermined location in spite of the intermittent activation and deactivation of a two-dimensional x-ray apparatus. A slot in each of the rings, moreover, forming gaps in alignment with the lengthwise guide slot permit the guide to be removed as the needle approaches the predetermined location.

Abstract: To establish the correct volar angle between the proximal radius and a distal fragment of the radius a cortical half pin with a self-threading screw is mounted in a collet. The collet is supported on a pair of members that clamp a volar plate under the collet, the volar plate has a hole in alignment with the half pin that enables the plate to pivot in a plane parallel to the members. The volar plate is tilted to contact the distal fragment and to be joined to the fragment. The half pin is screwed into the proximal radius and the members and collet are removed in order to allow the volar plate to be pressed back against the proximal radius and secured to the radius, thus establishing the correct volar tilt for the distal fragment relative to the proximal position of the radius.