Changes in carpal alignment following radial osteotomy for Kienböck's disease.

Changes in carpal alignment following radial osteotomy were studied in 30 patients with Kienböck's disease. The carpal height ratio and carpal-ulnar distance ratio were significantly less in wrists with Kienböck's disease than unaffected wrists. This observation implies proximal-ulnar translation of the capitate. In addition, the lunate-covering ratio increased significantly, reflecting radial translation of the lunate. Radial osteotomy corrected ulnar translation of the capitate and increased the radial translation of the lunate, thus increasing the lunate-covering ratio. The increased lunate-covering ratio is believed to increase the area of distribution of the axial load through the lunate by increasing the contact area with the radius. The satisfactory clinical outcome of radial osteotomy is believed to be due to this effect on carpal alignment.