Abstract
Aim
Fracture related infection (FRI) is classically defined as early (0–2 weeks), delayed (3–10 weeks) or late (>10 weeks). Treatment strategies reflect this, particularly with debridement and implant retention (DAIR), but there is little evidence to support this. This multinational study clarified the relationship between pathogens isolated and time from injury.
Methods
All confirmed FRI cases, managed surgically, at three hospitals were included. Data were analyzed on patient demographics, time from injury and pathogens isolated. Patients who underwent DAIR were also analyzed separately.
Results
433 FRIs were studied, including 51 early cases (mean time from injury 1.6 weeks), 82 delayed cases (mean 5.5 weeks) and 300 late cases (mean 467.3 weeks, range 11-3432 weeks). 140 patients underwent DAIR (mean time since injury 56.8 weeks, range 0-946 weeks).
Negative cultures were uncommon before 10 weeks but more frequent in late FRIs (4% vs 24%; p<0.0001). Over half of early and delayed FRIs were polymicrobial (59% and 56%) but only one quarter of late FRIs (26%; p=0.0004, p<0.0001). Cases treated with DAIR, at any time, had no difference in culture type (p=0.25).
Staphylococcus aureus was the most frequent isolate. There was no significant difference in the range of bacterial species isolated in early, delayed or late infections (p=0.20) or in those patients who underwent DAIR (p=0.56).
Conclusions
Bacterial species isolated in FRI do not change significantly over time. Up to 10 weeks, there was also no difference in the type of infection (polymicrobial, monomicrobial or culture negative). The increase in late culture negative FRIs may reflect more prolonged antibiotic use.
Decisions on FRI treatment should not assume microbiological differences related to time from injury. We found no evidence of more virulent organisms in early infections with less virulent species presenting later. The clinical relevance of classifying FRI by time from injury remains unclear.
