What is the recommended antibiotic regimen for open fractures?

Recommended Antibiotic Regimen for Open Fractures

For open fractures, a short-course, single-agent regimen using cephalosporins is recommended, with specific antibiotic selection and duration based on the Gustilo-Anderson fracture classification. 1

Antibiotic Selection by Fracture Type

Type I and II Open Fractures

• First-line: Cefazolin 2g IV slow infusion (1g if duration >4h)
• Duration: Limited to 24 hours maximum 2
• If penicillin allergic: Clindamycin 900mg IV slow infusion 2, 1

Type III Open Fractures

• First-line: Cefazolin 2g IV slow + gram-negative coverage
• Gram-negative options:
  • Piperacillin-tazobactam (preferred over aminoglycosides) 1
  • Gentamicin 5mg/kg/day (if aminoglycoside needed) 2
• Duration: Up to 48 hours maximum 2
• If penicillin allergic: Clindamycin 900mg IV slow + gentamicin 5mg/kg/day 2

Timing of Administration

• Administer antibiotics as soon as possible, ideally within the first hour post-trauma 1
• Initial dose should be given before surgical debridement 1
• For lengthy procedures (>2 hours), additional intraoperative doses should be administered 3

Duration of Therapy

• Type I/II fractures: 24 hours maximum 2, 1
• Type III fractures: Up to 48 hours maximum 2, 1
• Extended antibiotic therapy beyond these timeframes does not reduce infection rates but increases risks of antibiotic resistance 1

Special Considerations

Local Antibiotic Therapy

• Consider local antibiotic strategies as beneficial adjuncts, especially for Type III fractures:
  • Vancomycin powder
  • Tobramycin-impregnated beads
  • Gentamicin-coated nails 1

MRSA Coverage

• Consider MRSA coverage (vancomycin) when:
  • Patient has prior history of MRSA
  • Local prevalence of MRSA is high
  • Infection is clinically severe 1

Alternative Regimens

• Ceftriaxone has been shown to be equally effective as cefazolin for open fracture management with the advantage of 24-hour dosing 4
• For Type III fractures with severe contamination, single-drug regimens may include:
  • Piperacillin-tazobactam 3.375g every 6h or 4.5g every 8h IV
  • Ertapenem 1g every 24h IV 1

Important Caveats

• Antibiotics are an adjunct to, not a replacement for, thorough surgical debridement and irrigation 1
• Obtain appropriate cultures before starting antibiotics 1
• Adjust therapy based on culture results once available 1
• Antibiotic prophylaxis should be practiced even if antibiotic therapy is given before surgery to treat a distal trophic disorder 2
• Prolonged antibiotic use should be avoided and should not be continued through complete wound healing 1

Wound Management Principles

• Perform early surgical debridement and irrigation with normal saline as soon as possible (ideally within 24 hours) 1
• Consider negative pressure wound therapy after debridement 1
• Achieve wound closure within 7 days from injury when possible 1

By following these evidence-based recommendations, the risk of infection in open fractures can be significantly reduced while minimizing the adverse effects of prolonged antibiotic therapy.