Four tibiae removed from 30-40 years males

who died of accidents in less than 12 hours

were os- teomized at medium part. Then these tibiae were fixed by an unilateral hooked-sulcated external fixator （UHSEF）

and the bone-fixator system was used as a model of external fixation of tibial fracture. The axial compression

distraction

torsion

antero-posterior and lateral bending rigidly and the strain of the pins were determined in this system. Based on the results

we found that compared with the configuration of four paralled pins

the rigidity of the fan-like configuraton didn’t decrease significantly if the angle between lateral and medium pins was less than 45’. But the reverse was true when the frame separation increased from 5 to 8 cm. What’ more

the pin strain decreased if the rigidity of the system was improved. These data provided a theoretical basis of biomechanics for the improvement of UHSEF.