3-DIMENSIONAL DYNAMIC AO EXTERNAL FIXATION OF DISTAL RADIAL FRACTURES- A PRELIMINARY-REPORT

External fixation of unstable and intra-articular distal radial fractu res has become increasingly popular. Dynamic external fixation, allowi ng movement of the wrist during the fixation period, is a relatively n ew approach which may further improve functional end results. To permi t early functional treatment, the small AO external fixator was supple mented by a joint allowing all three degrees of rotational freedom. Th e centre of rotation is located at a point outside the device and lies approximately in the head of the capitate. With the natural centre of wrist rotation coincident with that of the fixator, admissable moveme nts of the wrist include both flexion-extension and radio-ulnar deviat ion, without threatening fracture reduction. In vitro testing and init ial clinical experience with a prototype are encouraging. Several impr ovements of the original design have been made and a multicentric clin ical study is scheduled for further evaluation of the new dynamic exte rnal fixator.