Some Kienböck's patients present with an abnormally large difference in length between the radius and the ulna, termed "ulnar variance", which is hypothesized to cause undue pressure on the lunate, contributing to its avascularity. In cases with such a difference, "radial shortening" is commonly performed. In this procedure, the radius (the lateral long bone) is shortened by a given length, usually between 2 and 5 mm, to relieve the pressure on the dying lunate. A titanium plate is inserted to hold the newly shortened bone together.