[Force distribution in the wrist following scaphotrapeziotrapezoid arthrodesis]

Scaphotrapeziotrapezoid (STT) arthrodesis has been proposed to stabilise the radial column and to redirect the load away from the lunate. Midterm effects on force transmission are still unclear. Six patients who were treated with triscaphe arthrodesis were examined after an average of 5 years using CT osteoabsorptiometry of both wrists. STT arthrodesis had been performed in four cases with Kienböck's disease type IIIb and in two cases of scaphotrapeziotrapezoid arthritis. At all contralateral wrists peak mineralisations were found beyond the lunate fossa and in the scaphoid fossa of the distal radius. At the side with STT arthrodesis there was only one peak. In five cases this density maximum was beyond the scaphoid fossa and in one case half beyond the lunate and half beyond the scaphoid fossa. Triscaphe arthrodesis allows load transmission from the lunate to the radial column.