Ilizarov hybrid external fixation for fractures of the distal radius: PartII. Internal fixation versus Ilizarov hybrid external fixation: Stability as assessed by cadaveric simulated motion testing

The in vitro stability of an Ilizarov hybrid external fixator was compared with that of a dorsal 3.5-mm AO T-plate in 8 unpaired, fresh-frozen upper e xtremities. A specially designed testing device that used computer-controll ed pneumatic actuators was used to simulate active finger, wrist, and forea rm motions by applying loads to relevant tendons. A comminuted extraarticul ar distal radius fracture was modelled using a dorsally based wedge osteoto my. Fracture stability was assessed using an electromagnetic tracking devic e to measure motion across the fracture site after randomized application o f the plate and the hybrid fixator. During simulated finger and wrist motio ns with the forearm pronated or supinated, motion of the distal fragment wi th the hybrid fixator applied was comparable to or statistically less than with the AO plate applied. During simulated forearm rotation, the stability provided by the 2 fixation types was similar, although the plate allowed s tatistically less radial-ulnar deviation of the fragment. In this model of a 2-part extra-articular distal radius fracture, the clinically meaningful stability of the Ilizarov hybrid external fixator was comparable to that of the dorsal AO plate. (J Hand Surg 2001;26A:218-227. Copyright (C) 2001 by the American Society for Surgery of the Hand.).