Does the CDC Surgical Wound Classification adequately predict postoperative infection in lower extremity fracture surgery?

OBJECTIVES

The purpose of this investigation was to evaluate the utility of the Centers for Disease Control (CDC) Surgical Wound Classification (SWC) in predicting surgical site infection (SSI) after orthopaedic trauma procedures.

DESIGN

Retrospective cohort study.

SETTING

Level I academic trauma center.

PATIENTS/

PARTICIPANTS

Adult patients with operatively treated fractures of the leg, ankle, and hindfoot between 2007 and 2022.

INTERVENTION: N/A.

MAIN OUTCOME MEASUREMENTS: Presence of SSI was determined by selective chart review of patients who met the screening variables for repeated procedures, open fracture, abscess or wound debridement, intraoperative cultures, or infectious disease consultation (n = 551).

RESULTS

Two thousand seven hundred ninety-one fractures among 2780 patients (n = 11 with bilateral fractures) were included. The overall infection rate was 2.3% (n = 63), and SWC was significantly associated with infection rates (I/clean: 1.0%, II/clean-contaminated: 3.4%, III/contaminated: 6.2%, IV/dirty: 9.8%, P < 0.001). When compared with Class I, Classes II through IV had increased odds of infection (odds ratio [OR] II: 3.5, P = 0.012; OR III: 6.8, P < 0.001; OR IV: 11.0, P < 0.001). Subgroup analysis of Classes II and III demonstrated no difference in odds of infection. When stratifying open versus closed fractures, there was no statistical association between CDC SWC and odds of infection.

CONCLUSIONS

The CDC SWC has notable limitations for patients with orthopaedic trauma, with ambiguity of classification assignment and decreased discriminatory ability within the central classes. While overall SWC is associated with infection, the relationship seems to be confounded by the effect of open versus closed fractures. Alternative classification systems may have improved utility for stratifying risk in orthopaedic patients.

LEVEL OF EVIDENCE: III.