ANTERIOR VERSUS POSTERIOR PROVISIONAL FIXATION IN THE UNSTABLE PELVIS- A BIOMECHANICAL COMPARISON

Pelvic ring injuries with associated hemorrhage often require provisio nal fixation to achieve tamponade. Biomechanics information regarding these provisional fixators is unknown. Six fresh-frozen cadaveric pelv ic specimens were physiologically loaded, first intact and then after each of the following modifications: disrupted-unilateral superior and inferior rami osteotomies, ipsilateral anterior and posterior sacroil iac joint, and sacrospinous and sacrotuberous ligament disruption; dis rupted and with placement of a Ganz pelvic resuscitation clamp; and di srupted and with placement of a simple anterior 2-bar external fixator . This injury resulted in significant motion at the disrupted rami and the injured sacroiliac joint, compared with the intact pelvic specime n. Motions at the superior ramus and injured sacroiliac joints were si gnificantly (p < 0.05) greater than the intact specimen, with both the external fixator and the Ganz clamp. Motions at the superior ramus an d injured sacroiliac joints were not significantly (p < 0.05) differen t when comparing the Ganz clamp to the external fixator. However, the anterior external fixator decreased motion to a greater degree at the disrupted rami, whereas the Ganz clamp decreased motion to a greater d egree at the disrupted sacroiliac joint.