Serum lactate has been utilized as a standard in guiding management of orthopedic injuries. Elevated preoperative lactate has been associated with a higher likelihood of postoperative complications. However, lactate's role in guiding operative timing in non-critical long-bone fractures has not been previously explored. This study investigates lactate's role in guiding surgical timing and predicting complications secondary to delayed definitive correction in non-critical long-bone fractures with Injury Severity Score <16.

Trauma is among the leading causes of death, disability, and hospitalizations each year worldwide. The majority of traumatic injuries are orthopedic in nature, making up nearly one million hospital encounters each year. According to the Center for Disease Control and Prevention, fractures are among the top 20 first-line diagnosis presenting to the emergency department. In recent years, the epidemiology of long bone fractures has been changing, with an increased incidence of fragility fractures in the elderly and high energy injuries affecting young adults. Fall-related fractures account for 61% of emergency orthopedic surgical procedures. Management of these orthopedic fractures is complex, and certain predictors such as lactate have been suggested to play a role in outcomes.

In the setting of trauma, the metabolic response of insufficient tissue perfusion is anaerobic glycolysis, with serum lactate as the final byproduct. Serum lactate serves as a circulating biomarker for organ oxygen supply and demand mismatch and is often used as a surrogate for tissue hypoxia. Normal blood lactate levels range from 0.5 to 2.2 mmol/L, with some variability in the upper limitation. Studies show early lactate clearance may be an important and independent prognostic variable in guiding management protocol for the resuscitation of trauma patients. Furthermore, several studies have presented more evidence that lactate levels can be considered a sensitive marker for patients in shock and during resuscitation with strong correlation with morbidity and mortality levels.

The goal of this study is to further investigate the role of serum lactate levels in guiding surgical timing and complications resulting from delay to the definitive surgical intervention in noncritical, traumatic patients with sustained long bone fractures.

Inclusion Criteria:

• All patients aged 18 years or higher with long bone fractures with Injury Severity Score <16

Exclusion Criteria:

• Non-long bone fracture surgeries performed within the first 72 hours
• Patients who underwent external fixation prior to surgery
• Patients with inconsistent or incomplete chart data Patients with polytrauma and life-threatening injuries.

This study was completed at the Arrowhead Regional Medical Center (ARMC) in San Bernardino County, California. The ARMC is a 456-bed acute-care teaching facility and ACS-verified level I trauma center. The ARMC emergency department (ED) is one of the busiest in the state of California with more than 100,000 visits and over 3,000 adult trauma cases annually.