Antibiotic Prophylaxis After ORIF
For closed fractures requiring ORIF, cefazolin 2g IV is the ideal antibiotic, administered as a single pre-operative dose with re-dosing every 4 hours intraoperatively if needed, and prophylaxis should be limited to the operative period (maximum 24 hours postoperatively). 1, 2
Primary Antibiotic Regimen
Cefazolin is the gold standard for ORIF prophylaxis:
- Administer 2g IV slow infusion 30-60 minutes before surgical incision 1, 3
- Re-dose with 1g if surgical duration exceeds 4 hours 1, 2, 3
- Discontinue within 24 hours postoperatively for closed fractures 1, 4
The American Academy of Orthopaedic Surgeons strongly recommends this regimen based on evidence showing it reduces infection rates from 8.3% to 3.6% in closed fractures 2. Research confirms that extending prophylaxis beyond 24 hours provides no additional benefit—a randomized controlled trial found no significant difference in surgical site infection rates between 23-hour cefazolin prophylaxis (2.4%) versus placebo (5.2%) when proper pre-operative dosing was used 4.
Alternative Regimens for Penicillin Allergy
For patients reporting penicillin allergy, the approach depends on allergy severity:
- First-line alternative: Clindamycin 900mg IV slow infusion, with 600mg re-injection if duration exceeds 4 hours 1, 2
- For severe reactions or MRSA risk: Vancomycin 30mg/kg IV over 120 minutes, completed at least 30 minutes before incision 1, 2
Critical consideration: Most patients with reported penicillin allergy (90-95%) can safely receive second or third-generation cephalosporins like cefuroxime 1.5g IV, as true cross-reactivity is only 2-5% 2. Avoid cephalosporins only in patients with documented severe T-cell-mediated reactions (Stevens-Johnson syndrome, toxic epidermal necrolysis) 2.
Duration: Why 24 Hours Maximum
Extending antibiotics beyond the operative period increases resistance without reducing infections:
- A multicenter study of 269 patients found no benefit from prolonged antibiotic courses after curative surgery 5
- An Indian randomized trial demonstrated equivalent infection rates (2% vs 2.1%) between 24-hour prophylaxis and 5-day conventional regimens, while the shorter course cost 92% less 6
- A retrospective study of 347 young, healthy patients showed no statistical difference in infection rates between those receiving prophylaxis (3.3%) versus no prophylaxis (1.9%), suggesting that in low-risk patients, even 24 hours may be excessive 7
Special Considerations for Open Fractures
Open fractures require different management:
- Start antibiotics immediately upon presentation 2
- For Gustilo-Anderson Type I: Use cefazolin 2g IV with same dosing as closed fractures 1
- For Type II-III: Add gram-negative coverage with piperacillin-tazobactam 2g IV or aminoglycoside 1
- Continue for 48-72 hours maximum (not applicable to standard ORIF question) 1, 2
Common Pitfalls to Avoid
Do not automatically avoid cephalosporins in penicillin allergy: Obtain specific allergy history asking about reaction type (rash vs. anaphylaxis) and timing 2. The vast majority can safely receive cefuroxime or cefazolin 2.
Do not extend prophylaxis beyond 24 hours without documented infection: This increases antibiotic resistance, costs, and adverse effects without reducing surgical site infections 4, 6, 5. The only exception is prosthetic joint surgery where 3-5 days may be considered 3.
Do not delay pre-operative dosing: Antibiotics must be infused completely before incision, particularly vancomycin which requires 120 minutes 2. If using a tourniquet, complete infusion before inflation 2.
Do not rely solely on antibiotics: They are adjuncts to proper surgical technique, not replacements for meticulous debridement and wound management 2.
Risk Factors Requiring Vigilance
Patients with diabetes mellitus have 4.33 times higher risk of surgical site infection (95% CI 1.30-14.38) and warrant closer postoperative monitoring, though this does not justify extending prophylaxis duration 4.