Anatomical bases of the pediculated pisiform transplant and the intercarpal fusion by Graner in Kienböck's disease.

Anatomic characteristics of the lunate, the pisiform and the capitate were compared in order to support the use of a pisiform transplant or the intercarpal fusion by Graner in advanced stages of Kienböck's disease. Fifty lunate and pisiform bone pairs and 20 wrist specimens served for morphological and functional investigations. In view of the present results, the pisiform, after a rotation of 90 degrees, should be implanted in the lunate box with its longitudinal diameter oriented to the dorsopalmar plane. Despite the small pisiform volume, maintainance of carpal height is assured by its relatively large dorsopalmar diameter. The rotated position permits use of existing soft tissue structures and improves the conditions of force transmission. Measurements comparing the radii of curvature of the original lunate and the substitute pisiform surfaces show a good correspondence proximally and a reduction of the articular congruity distally, due to the flatness of the pisiform surface. The palmar convexity of the pisiform adapts better to the distal radius facet than the capitate head, which replaces the lunate in Graner's surgical procedure.