A NEW AIMING DEVICE FOR THE DISTAL INTERL OCKING SCREWS OF THE UNREAMED TIBIAL NAIL (UTN)

The complex 3D-problem of distal aiming is reduced to three easier 2D- steps: (1) Preadjustment of an aiming handle: This defines rotation an d distance of distal locking holes relative to the proximal nail end. During insertion, the nail usually bends. This is why a readjustment i s necessary. (2) Re-adjustment for transverse holes: At the level of t he distal nail end, a roughly placed ''contact hole'' is drilled. An a symmetric spacer is inserted, placed directly onto the nail and connec ted with the aiming arm. By this re-adjustment, direction and plane of both distal transverse holes are defined. (3) Re-adjust ment for ap h ole: The upper transverse hole is over-reamed (diameter 6.0 mm). A cen tering unit inserted into this channel locks the nail to the aiming ar m. After this readjustment in the frontal plane, the ap hole is define d. Advantages: Simple and reliable; drill holes more precise; radiatio n-free distal targetting.