Abstract
Aim
Since surgical site infections (SSIs) remain among the most common complications of orthopedic (trauma) surgery, there has been unwavering attention for potential predictors of a SSI.
Specifically in surgical fields with a high complication rate, such as foot/ankle surgery, risk factor identification is of great importance. Recently, some studies have suggested environmental factors such as season to be of influence on the number of SSI. Specifically patients operated on in the summer are reported to have a higher incidence of SSIs, compared to other seasons. The aim of this study is to identify if “seasonality” is a significant predictor for SSI in a cohort of (trauma) surgical foot and ankle procedures.
Method
This retrospective cohort study included all patients undergoing trauma related surgery (fracture fixation, arthrodesis, implant removal and tendon repair) of the lower leg, ankle and foot. Procedures were performed at a single Level 1 Trauma Center in the Netherlands between September 2015 until February 2019. Potential risk factors/ confounders for SSI were identified using univariate analysis (Chi-Square/Mann-Whitney U). Procedures were divided in two groups: 1) performed in summer (June, July or August), 2) not performed in summer (September-May). The number of SSIs was compared between the 2 groups, correcting for confounders, using multivariate regression.
Results
A total of 605 procedures were included, largely fracture fixation (371, 61.2%). Patients were on average 46 y/o and the majority was male (369, 60.9%). The total number of SSIs was 34 (5.6%). Age, American Society of Anesthesiologists (ASA) classification (1–2 or 3–4) and open fractures were identified as possible predicting factors of SSI. No difference in SSIs was found between summer and other seasons, neither in univariate analysis (4 (3.2%) vs 30 (6.3%), p=0.271), nor when corrected for confounders. Moreover, in multivariate analysis only an ASA of >2 and an open fracture remained as independent predictors of SSI.
Conclusions
No seasonality could be identified in the rate of SSI after trauma surgery of the lower leg, ankle and foot in this cohort. A possible explanation for this lack of effect could be the temperate oceanic climate of the Netherlands. Larger temperature and precipitation differences may also influence the incidence of SSIs. However, previous studies suggesting seasonality in SSIs might also be purely based on coincidence, especially when uncorrected for confounders.
