Antibiotic Prophylaxis for Extremity Lacerations

Classification of Wounds and Antibiotic Indications

Surgical wounds are classified into four types based on infection risk: class I (clean), class II (clean-contaminated), class III (contaminated), and class IV (dirty-infected), according to the American Academy of Orthopaedic Surgeons 1
By definition, antibiotic prophylaxis applies only to class I and II surgical wounds, while class III and IV wounds require therapeutic antibiotics, as stated by the American Academy of Orthopaedic Surgeons 1
Simple extremity lacerations without significant contamination are considered clean wounds (class I) and do not routinely require antibiotic prophylaxis, as recommended by the American Academy of Orthopaedic Surgeons 2, 1

Antibiotic therapy (not prophylaxis) is indicated for contaminated or dirty wounds, according to the American Academy of Orthopaedic Surgeons 2, 1
Consider antibiotics for wounds with gross contamination, as suggested by the American Academy of Orthopaedic Surgeons and other guidelines 2, 3
Open fractures require antibiotics to be started as soon as possible, as recommended by the American Academy of Orthopaedic Surgeons 2, 4
High-velocity injuries with significant tissue damage may require antibiotics, according to the American Academy of Orthopaedic Surgeons 2

For contaminated wounds requiring antibiotics, a first-generation cephalosporin such as cefazolin is the first-line choice, as recommended by the American Academy of Orthopaedic Surgeons 2
For more severe injuries with gram-negative risk, consider adding an aminoglycoside, as suggested by the American Academy of Orthopaedic Surgeons 2
For wounds with soil contamination or ischemic tissue, add penicillin for anaerobic coverage, particularly against Clostridium species, as recommended by the American Academy of Orthopaedic Surgeons 2

When antibiotics are indicated for contaminated wounds, they should be continued for 48-72 hours, as recommended by the American Academy of Orthopaedic Surgeons 2
For open fractures specifically, antibiotics should be continued for 3 days (type I and II fractures) or 5 days (type III fractures), as suggested by the American Academy of Orthopaedic Surgeons 4

Failing to recognize when a wound is truly contaminated and requires therapeutic antibiotics rather than prophylaxis, as warned by the American Academy of Orthopaedic Surgeons 1
Using antibiotics as a substitute for proper wound cleaning and debridement, as cautioned by the American Academy of Orthopaedic Surgeons and Praxis Medical Insights 3
Continuing antibiotics beyond recommended duration when indicated, as advised against by the American Academy of Orthopaedic Surgeons 2