What antibiotics are recommended for Gustillo classified open fractures?

Antibiotic Recommendations for Gustillo Open Fractures

Initial Antibiotic Selection

For Gustilo Type I and II open fractures, start cefazolin (or clindamycin if penicillin-allergic) immediately upon presentation, while for Gustilo Type III fractures, use piperacillin-tazobactam 3.375g IV every 6 hours as a single-agent regimen that provides both gram-positive and gram-negative coverage. 1

Type I and II Fractures

• Administer cefazolin as monotherapy targeting Staphylococcus aureus, streptococci, and aerobic gram-negative bacilli 2
• For penicillin allergy, use clindamycin 900mg IV every 8 hours 1
• Extended-spectrum antibiotic coverage beyond gram-positive organisms does not decrease infectious complications, hospital length of stay, or mortality for Type I or II fractures 2
• Research confirms that gram-positive coverage alone results in equivalent infection rates (8.6%) compared to broad-spectrum coverage (10.8%) with significantly lower cost 3

Type III Fractures

• Piperacillin-tazobactam is the preferred single agent, providing comprehensive coverage without the need for aminoglycosides 4, 1
• The traditional cefazolin plus aminoglycoside combination is an alternative, though current AAOS guidelines favor piperacillin-tazobactam 4
• For penicillin allergy, use clindamycin 900mg IV every 8 hours plus gentamicin or amikacin 1
• Adding vancomycin or gentamicin to piperacillin-tazobactam does not appear to be helpful 4

Timing of Administration

• Start antibiotics immediately upon presentation—delaying beyond 3 hours significantly increases infection risk 2
• For surgical intervention, administer antibiotics within 60 minutes before incision 2
• The traditional "six-hour rule" for surgery has been debunked; surgery can safely occur within 24 hours for most open fractures 4, 1

Duration of Therapy

Limit systemic antibiotics to 24-72 hours post-injury or 24 hours after wound closure, as prolonged courses beyond 72 hours provide no additional benefit in preventing infection. 2, 5

• Meta-analysis of 6,692 open fractures demonstrates no difference in infection rates between <72 hours (10%) versus >72 hours (9.2%) of antibiotic treatment 5
• This holds true even for Gustilo III fractures: 17.7% infection rate with <72 hours versus 21.3% with >72 hours (p=0.39) 5
• Even shorter regimens of 24-48 hours are equivalent to prolonged courses 5

Local Antibiotic Adjuncts

Consider local antibiotic delivery systems as adjuncts during definitive surgery, particularly for Type III fractures with bone loss. 4, 1

• Vancomycin powder, tobramycin-impregnated beads, and gentamicin-covered implants are all beneficial options 4, 2
• These are especially useful in Type III fractures with significant bone loss 2
• Gentamicin-coated implants have demonstrated safety in clinical application 2

Dosing Adjustments

• For cefazolin, reinject 1g if surgical duration exceeds 4 hours to maintain effective coverage 2
• Adjust cephalosporin dosing based on patient weight and renal function 2
• For vancomycin (if used as alternative for severe beta-lactam allergy), administer 30mg/kg over 120 minutes 2

Critical Pitfalls to Avoid

• Do not routinely add vancomycin to the regimen unless there are specific institutional MRSA concerns 2
• Do not continue antibiotics beyond 72 hours without evidence of active infection—this increases resistance and C. difficile risk 1, 5
• Do not use antiseptic irrigation solutions or soap additives—simple saline is equivalent and recommended 1, 2
• Do not close the wound before operative debridement, as this traps contamination 1
• Do not delay antibiotic administration beyond 3 hours post-injury 2, 6

Special Considerations

• For wounds with gross contamination (farm injuries, fecal contamination), consider adding penicillin even for lower-grade fractures to cover anaerobic organisms 2
• Current practice shows only 17.2% adherence to traditional cefazolin plus aminoglycoside for Type III fractures, with most centers using alternative regimens 7
• Recent research supports ceftriaxone monotherapy as non-inferior to traditional regimens for Type III fractures (14% vs 19% infection rate, p=0.20) 8