Effect of Pelvic Binder Placement on Ota Classification of Pelvic Ring Injuries Using Computed Tomography. Does It Mask the Injury?

Objectives:To assess the diagnostic sensitivity of computed tomography (CT) in patients with an unstable pelvic ring injury after application of a pelvic binder.Design:An institutional review board approved retrospective study from 2003 to 2010.Setting:Level 1 trauma center.Patients:Inclusion criteria were patients in our trauma database with AO/OTA B or C type pelvic ring injury, which first had an anterior-posterior pelvic x-ray followed by application of a pelvic circumferential compression device (PCCD), then a CT, and a fluoroscopic stress examination under anesthesia (FEUA) (used as gold standard). Of 867 patients, 43 met the inclusion criteria.Intervention:A senior Orthopaedic Resident and Trauma Attendings assessed x-rays, CTs, and FEUAs. Binomial test was used to compare imaging against final diagnosis.Results:In Anterior Posterior Compression/Vertical Shear (OTA 61-B1, 61-B3.1, 61-C) injury patterns, prebinder x-rays were diagnostic in 69.4% (CI, 51.9%-83.7%) of cases, compared with 50% (CI, 32.9%-67.1%) with CT + PCCD. The x-ray was superior to CT + PCCD for identification of the anterior pelvic injury (McNemar exact P = 0.0352). If x-ray and CT + PCCD were viewed in tandem, 83.3% (CI, 67.2%-93.6%) of classifications were in agreement with the FEUA. For lateral compression mechanisms, the binder did not effect of the sensitivity of the CT except in the open book component of an lateral compression 3 (61-B3.2) mechanism.Conclusions:The placement of a pelvic binder has the potential to mask the severity of unstable pelvic ring injuries when relying only on CT for diagnosis. Fluoroscopic manual pelvic stress examination under anesthesia is an essential adjunct when a binder is placed before imaging.Level of Evidence:Diagnostic level III. See Instructions for Authors for a complete description of levels of evidence.