Ancilliary instrument for optimally positioning a rod-form joint prosthesis in long bone, e.g. the femur, comprises mutually movable elements for transferring position of trial prosthesis to final prosthesis

摘要

An ancilliary instrument (1) for positioning a rod-form joint prosthesis to be implanted in a long bone, after locating and positioning a trial prosthesis, comprises two mutually movable elements (2, 3). One (2) element is fixable to the trial prosthesis and the other (3) has a supporting portion (34) to be applied against the bone. The mutual positions of the elements are blocked and marked, so that the position of the trial prosthesis can be transferred to the final prosthesis. An ancilliary instrument (1) for positioning a rod-form joint prosthesis to be implanted in a long bone, after provisionally locating and correctly positioning a trial prosthesis, comprises two mutually movable elements (2, 3). One (2) element has feeler(s) (23) for fixing to the trial prosthesis and the other (3) has a supporting portion (34) to be applied against a reference zone provided on (or on a piece fixed to) the bone when the trial prosthesis has been positioned. Blockers (4, 36) and markers (10, 11) for the mutual positions of the elements are provided, so that the determined position of the trial prosthesis can be transferred to the final prosthesis. Independent claims are included for: (1) a joint prosthesis to be implanted in the centromedullar channel of long bone, after blocking and marking the mutual positions of two flat blades (20, 30) of an instrument as above, where the prosthesis rod surface has a graduation corresponding to the position markers (10, 11) of the instrument; and (2) a combination of the instrument and the prosthesis as above, where the prosthesis is a femoral prosthesis for the hip joint.