ABSTRACT
Objective To observe the biomechanical effect of sacroiliac screw fixation with dif-ferent needling points in treatment of extorsion pelvic instabihty so as to provide experimental basis for clinical application. Methods Ten fresh adult pelvis specimens were fixated by sacroiliac screw with needling points B (2.5 cm anterior to posteroinferior iliac spine and 40. cm posterior to greater sciatic notch), A (0.1 cm anterior to the same horizontal plane of point B) and C ( 1.0 cm posterior to the same horinzontal plane of point B). The shifting of the pubic symphysis diastasis and the sacroiliac joint crack under the same extorsion force was measured in integrity ligament group, point A group, point B group and point C group to compare the stability of different needling points. Results In confronting extor-sion force, integrity ligament group and point C group were obviously inferior to point A group and point B group (P<0.05 ) but there was no statistical difference between point B group and point A group (P > 0.05). As for the stability of the sacroiliac joint, there was statistical difference among all groups ( P < 0.05 ), while there was no statistical difference between integrity ligament group and point B group ( P > 0.05). Conclusion Point B is the most stable, safe and effective needling point.