Incidence and Associated Factors of Surgical Site Infection in Patients Undergoing Foot and Ankle Surgery: A 7-Year Cohort Study

Research Type: Level 3 - Retrospective cohort study, Case-control study, Meta-analysis of Level 3 studies Introduction/Purpose: Surgical site infections (SSIs) account for 31% of all hospital-acquired infections, significantly impacting postoperative recovery and healthcare costs. Foot and ankle surgeries present infection rates between 0.5% and 6.5%, with trauma cases and comorbidities being key risk factors. Despite previous studies, long-term data on infection incidence and predictive factors remain limited. This 7-year cohort study aimed to determine the incidence of SSIs in foot and ankle surgeries and identify independent predictors of infection, particularly differentiating superficial and deep infections. Understanding these risk factors is essential for optimizing infection control protocols and refining perioperative management strategies to improve surgical outcomes. Methods: This retrospective cohort study included 2,180 patients undergoing foot and ankle surgery between 2014 and 2020 in a private hospital. Elective and trauma-related procedures were included, excluding cases of pre-existing infections, open fractures, and septic arthritis. SSIs were classified as superficial (requiring local wound care or oral antibiotics) or deep (requiring surgical debridement or implant removal). Data on age, sex, diabetes mellitus (DM), systemic arterial hypertension (SAH), smoking, ASA score, and BMI were collected. Multivariate logistic regression was used to assess independent predictors of SSIs, with statistical significance set at p < 0.05. The primary outcome was infection incidence, while secondary outcomes included risk factor analysis and infection severity stratification. Results: The overall SSI incidence was 4% (83/2,180 cases), with 2.8% superficial and 1.2% deep infections. Smoking (OR 2.9, 95% CI 1.4–5.3, p = 0.001) and ASA score >2 (OR 3.4, 95% CI 1.2–8.4, p = 0.013) were independent predictors of infection. The deep infection group had significantly higher rates of smoking (p = 0.002), systemic hypertension (p = 0.018), and trauma-related procedures (p = 0.049). No significant associations were found between infection and diabetes mellitus (p = 0.404) or obesity (p = 0.816). Trauma surgeries, particularly ankle fractures, had the highest infection rates, reinforcing the need for enhanced infection control measures in high-risk patients. Conclusion: This 7-year cohort study confirmed a 4% SSI incidence in foot and ankle surgeries, with smoking and ASA score >2 emerging as significant risk factors. Trauma-related procedures, particularly ankle fractures, had higher infection rates, emphasizing the importance of preoperative risk stratification and perioperative infection control. Surprisingly, diabetes and BMI were not significant predictors, possibly due to effective preoperative optimization. These findings support the implementation of targeted preventive strategies, particularly in high-risk patients, to reduce infection rates and improve surgical outcomes. Characterization of the sample according to the presence of infection This table presents the demographic and clinical characteristics of patients undergoing foot and ankle surgery, stratified by infection status (no infection, superficial infection, and deep infection). Trauma cases (p = 0.049), arterial hypertension (p = 0.018), ASA score ≥ II (p < 0.001), smoking (p = 0.002), and overweight status (p = 0.002) were significantly associated with infection. Diabetes mellitus (p = 0.687) and BMI (p = 0.321) were not statistically significant predictors. The findings suggest that preoperative risk factors such as smoking, ASA score, and hypertension should be considered in infection prevention strategies for foot and ankle surgery patients.