Inclusion Criteria

Direct admission to hospital from scene of injury, or if transferred, admitted no more than 6 hours from injury
Full trauma activation with either direct admission to Intensive Care Unit (ICU) or other higher level of care, or taken directly to surgery and admitted to ICU after surgery;
Sustaining at least one operative orthopaedic injury to the pelvis, acetabulum, femur, or diaphyseal tibia with planned definitive fixation to occur prior to discharge.

Exclusion Criteria

Non-survivable head trauma.
Signs of severe traumatic brain injury indicated by a GCS of < 7 at the time of admission and no improvement in the GCS by the time of consent at 48hr after admission.
Spinal cord injury with likely permanent neurologic deficits
Pre-existing organ dysfunction or failure prior to their injury, including but not limited to end-stage renal disease, liver failure, congestive heart failure, or severe COPD requiring home oxygen.
Qualifying orthopaedic injury primarily a periarticular fracture (tibial pilon or plateau) with planned delay to definitive fixation for soft tissue reasons.
Primary blood draw could not be obtained within 3 hours of presentation
Patient is pregnant
Patient is a prisoner/incarcerated
Patient or legally authorized representative (LAR) unable to provide consent prior to 48 hour blood draw.