J. Kraisarin, MD; D.G. Dennison, MD; L.J. Berglund, BS; K.N. An, PhD and Alex Y. Shin, MD

Abstract: Clinical results following four-corner arthrodesis vary and suggest that nonunion may be related to certain fixation techniques. The purpose of our study was to examine the displacement between the lunate and capitate following a simulated four-corner arthrodesis with the hypothesis that three types of fixation (Kirschner wires, dorsal circular plate, and a locked dorsal circular plate) would allow different amounts of displacement during simulated wrist flexion and extension. Cadaver wrists with simulated four-corner arthrodeses were loaded cyclically either to implant failure or until the lunocapitate displacement exceeded 1mm. The locked dorsal circular plate group was significantly more stable than the dorsal circular plate and K-wires groups (p=0.018 and p=0.006). While these locked dorsal circular plates appear to be very stable our results are limited only to the biomechanical behavior of these fixation techniques within a cadaver model.