The primary aim of this investigation is to prospectively and clinically validate a novel, reproducible method of quantitative application of compressive stress to a LC1 pelvic ring injury of indeterminate stability for the purpose of assessing quantitative pelvic ring displacement.

patients will receive a diagnostic intervention with multiple x-rays. These x-rays will be taken as different levels of force are applied to the pelvis. This will be used to determine instability as an indication for surgical intervention to stabilize the pelvic ring.

Inclusion Criteria:

• Age > 18 years
• Acute emergency department admission or transfer to Los Angeles County + USC Medical Center
• Presentation within 3 weeks of injury
• Blunt or blast mechanism of traumatic injury
• Lateral compression pelvic ring injury with unilateral incomplete disruption of the posterior arch (OTA/AO 61B1.1/2.2; Young Burgess LC1) on radiographs and/or computed tomography scan of the pelvis obtained per routine care
• LC1 pelvic ring injuries occurring in isolation are virtually never associated with hemodynamic instability or critical patient condition
• Stress examination of LC1 pelvic ring injury is standard of care
• Patient must speak either English or Spanish

Exclusion Criteria:

• Volume expanding pelvic ring injury (Young-Burgess APC-2 and 3, LC-3, vertical shear, and combined mechanism of injury (CMI) (Tile B and C patterns; OTA codes 61-B and 61-C).
• Volume expanding pelvic ring injury injuries represent the types of pelvic ring disruption responsible for pelvic hemorrhage and hypotension and are correlate with patient hemodynamic instability as well as critical injuries
• Volume expanding pelvic ring injury injuries warrant stabilization with circumferential pelvic compression.
• Patients with volume expanding pelvic ring injury are not clinically appropriate for this study.
• Hemodynamic instability or hypotension angioembolization (AE), preperitoneal pelvic packing (PPP), or Resuscitative Endovascular Balloon Occlusion of the Aorta (REBOA) to obtain or maintain hemodynamic stability
• Bladder, vaginal, rectal, colonic, or other abdominal or pelvic organ injury precluding safe application of circumferential pelvic compression device
• Patient likely to have severe problems with maintaining follow- up due to at least one of the following:
• Patient has been diagnosed with a severe psychiatric condition
• Patient is intellectually challenged without adequate family support
• Patient lives outside the hospital's catchment area
• Follow-up is planned at another medical center
• Patients who are prisoners or homeless