Deep infections after low-velocity ballistic tibia fractures are frequently polymicrobial and recalcitrant.

OBJECTIVES

To identify risk factors for developing a fracture-related infection in operatively treated ballistic tibia fractures and to report the microbiologic results of intraoperative cultures.

DESIGN

Retrospective review.

SETTING

Level 1 trauma center.

PATIENTS/PARTICIPANTS: One hundred thirty-three adults with operatively treated low-velocity ballistic tibia fractures, from 2011 to 2021.

INTERVENTION

One dose of prophylactic cefazolin or equivalent as well as perioperative prophylaxis.

MAIN OUTCOME MEASUREMENTS

Deep infection rate.

RESULTS

The deep infection rate was 12% (16/134) with no significant difference in injury characteristics, index surgical characteristics, or time to antibiotics between the groups ( > 0.05). Patients who were slightly older (35.5 vs. 27 median years, = 0.005) and with higher median body mass indexes (BMIs) (30.09 vs. 24.51, = 0.021) developed a deep infection. 56.3% of patients presented with signs of infection within the first 100 days after injury. Nine patients had polymicrobial infections. There were 29 isolated organisms, 69% were uncovered by first-generation cephalosporin prophylaxis (anaerobes, gram-negative rods, ), and 50% of patients developed recalcitrant infection and required a second reoperation where 6 organisms were isolated, half of which were not covered by first-generation prophylaxis ().

CONCLUSIONS

We found a deep infection rate of 12% among ballistic tibia fractures receiving standard-of-care antibiotic prophylaxis. Increased age and body mass index were associated with deep infections. Half became recalcitrant requiring a second reoperation. 66.7% of isolated organisms were not covered by first-generation cephalosporin prophylaxis. Consideration should be given to treatment options such as broader prophylaxis or local antibiotic treatment.

LEVEL OF EVIDENCE

IV.