Evans technique. A, The incision should start at point of greatest tension when ulnar force is applied to radial side of wrist. Defect that opens up should be length of proximal flap A and another flap B at 90 degrees on ulnar side. B, Flap after transposition. Flap A has been rotated from dorsal to radial on wrist, and flap B rotated from ulnar to dorsal.