RESUMO
The dynamic ASIF-BM external fixator incorporates telescopic tubes for axial dynamization and angled bayonet screws to keep the tubes parallel to the bone axis, that is essential for gliding, and adjustment of rotation. The results after treatment of 70 type II and III open tibial fractures with static ASIF and dynamic ASIF-BM frames were analysed. Of the fractures, 32 were treated with the delta ASIF static frame, the other 38 with delta and uniplanar dynamic ASIF-BM frames. The groups were found to be comparable. The results of the study confirm that tubular external fixation is a safe method for treating the bone and soft tissue lesions in such fractures. The comparative study shows that axial compression, using the ASIF-BM device, with early weight bearing, gave a higher rate of union (97 per cent against 87 per cent with the ASIF frame), a shorter healing time (19 weeks against 29 weeks with the ASIF frame) and a decreased need for bone grafting (21 per cent against 84 per cent with the ASIF frame). The incidence of pin track infection was also decreased in dynamic frames. Thus it seems that the ASIF-BM dynamic fixator has a valuable part to play as a definitive mode of therapy for severe open fractures of the tibial shaft.