[Standardised operation technique for ulna-shortening with a new sliding-hole plate].

Ulna-shortening is a widely accepted procedure for the treatment of ulna-impaction syndrome. High rates of non-unions however necessitate improving the operation technique. The new device introduced in this study is a 7-hole plate in which two proximal holes are sliding-holes. By correct placement of two distal screws and two screws in the sliding-holes, rotational stability is guaranteed. The osteotomy is performed while the plate is loosely fixed to the ulna. After fixation of the two distal screws, the sliding-holes facilitate reposition with a good closure of the osteotomy gap. Excentric placement of two more screws and placement of a lag screw across the oblique osteotomy leads to further compression at the osteotomy site. Ulna-variance can be adjusted exactly. So far the plate has been implanted in 15 patients. Ulna-variance was reduced from + 2 to - 2.2 mm. The clinical results are comparable to those of ulna-shortenings in the literature. The sliding-hole plate allows an exact connection with good closure of the osteotomy without malrotation. With this simplified technique, the risk of non-union can be reduced.