Pin Malposition in External Fixator Stabilization of Combat-Related Pelvic Fractures

The purpose of this study was to compare the accuracy of pin placement in patients with unstable pelvic fractures undergoing either iliac crest or supra-acetabular external fixation. A retrospective review was performed of computed tomography (CT) scans and injury characteristics for all patients presenting to a North Atlantic Treaty Organization Medical Treatment Facility with data entered into the Department of Defense Trauma Registry from January 2008 to October 2013 who underwent pelvic external fixation for unstable pelvic ring injuries. Thirty-two patients were analyzed. Sixteen patients underwent damage control iliac crest-based and 16 patients underwent supra-acetabular-based external fixation. There was no significant difference in patient characteristics at presentation between the two groups. Pin malposition rate on CT scan was 50/64 (78.1%) for the iliac crest group and 3/32 (9.4%) for the supra-acetabular group. Pin malposition was correlated with increasing Injury Severity Score, Abbreviated Injury Scale (AIS) head score, and AIS face score. The review concluded that iliac crest-based external fixation has a significantly higher rate of pin malposition than supra-acetabular-based external fixation.