From the Guidelines
An open fracture requiring IV antibiotics is defined as a bone break where the bone has penetrated through the skin, creating a direct communication between the bone and the external environment, and the standard regimen typically includes a first-generation cephalosporin such as cefazolin for Gram-positive coverage, with additional coverage for Gram-negative organisms and anaerobes as needed, based on the severity of the fracture and degree of contamination, as recommended by the most recent guidelines 1.
Definition and Classification
The definition of an open fracture is a bone break where the bone has penetrated through the skin, creating a direct communication between the bone and the external environment. This type of fracture requires immediate IV antibiotic therapy to prevent infection, as the exposed bone and surrounding tissues are contaminated with environmental bacteria. The Gustilo-Anderson classification system is commonly used to classify open fractures, with Type I being the least severe and Type III being the most severe.
Antibiotic Regimen
The standard regimen for open fractures typically includes a first-generation cephalosporin such as cefazolin (1-2g IV every 8 hours) for Gram-positive coverage. For more severe open fractures (Gustilo type II or III), additional coverage with an aminoglycoside like gentamicin (5-7mg/kg IV daily) is recommended for Gram-negative organisms, and metronidazole (500mg IV every 8 hours) or clindamycin (600-900mg IV every 8 hours) may be added for anaerobic coverage if there is significant soil contamination.
Timing and Duration of Antibiotics
Antibiotics should be started as soon as possible, ideally within 3 hours of injury, and continued for 24-72 hours depending on the severity of the fracture and degree of contamination. The rationale for this approach is that open fractures have infection rates of 3-50% depending on severity, and early antibiotic administration significantly reduces this risk by preventing bacterial colonization before it becomes established in the traumatized tissues, as supported by recent guidelines 1.
Key Considerations
- The use of local antibiotic strategies as an adjunct to systemic antibiotics may be beneficial, as recommended by recent guidelines 1.
- The OTA open fracture classification system (OTA-OFC) provides another validated measure of the severity of these injuries and reportedly has greater interobserver agreement compared with the Gustilo-Anderson classification.
- Negative pressure wound therapy (NPWT) may mitigate the risk of developing a surgical site infection (SSI) and concomitantly the need for revision surgery in closed fracture fixation after major extremity trauma, but its role in open fractures is less clear.
From the Research
Definition of Open Fracture
- An open fracture is defined as a fracture that communicates with the environment through a skin wound, causing substantial morbidity after traumatic injury 2.
- The Gustilo-Anderson classification is used to guide prophylactic antibiotic therapy, as different types of open fractures have varying rates of surgical site infections with different combinations of pathogens 3.
Antibiotic Prophylaxis
- Current evidence supports the administration of prophylactic systemic antibiotic agents to patients with open extremity fractures to decrease infectious complications 2.
- The choice of antibiotic and duration of therapy remains variable between institutions, and is not standardized 3.
- Most publications recommend prophylactic systemic antibiotics, with gram-positive coverage for less severe injuries and broad antimicrobial coverage for more severe injuries 4.
IV Antibiotics for Open Fractures
- IV antibiotics are recommended for open fractures, with the goal of decreasing infectious complications, hospital length of stay, and mortality 2, 5, 6.
- The specific antibiotic regimen and duration of therapy may vary depending on the type and severity of the fracture, as well as the presence of other factors such as bone loss or clinical signs of active infection 2, 6.