Potential Origins of Acute Surgical Site Infections after Orthopedic Surgery: A Prospective Evaluation in Switzerland

Background: With an ever-increasing population of elderly orthopedic patients experiencing co-morbidities and immune suppression, the proportion of postoperatively acquired surgical site infections (SSIs) may increase compared to prior decades, where the majority of SSIs were acquired intraoperatively. A comprehensive overview would aid in allocating resources under these conditions. Methods: We examined a prospective database containing data from four prospective randomized clinical interventional trials and surveillance registers. We concentrated on cases of acute SSIs with complete documentation from the 2019–2024 period, during which the number and proportion of clinically frail patients treated at our tertiary center increased significantly. In this assessment, surgeons and Infectious Physicians specialized in orthopedic infections evaluated each SSI episode clinically by searching medical and nursing notes for postoperative events that could possibly be associated with postoperative surgical site infection. Results: Among 370 SSI cases, we estimated that 241 infections (65%) were acquired intraoperatively and 129 (35%) postoperatively. The three most frequent reasons for postoperative SSIs were skin breakdowns, surgical complications (hematoma; dehiscence), and ischemic necrosis. These (new) risk associations differed significantly from the SSI risk reported in the literature on middle-aged orthopedic patients. Conclusions: According to our prospective evaluation, one-third of acute orthopedic SSIs in the last six years might be associated with a postoperative complication. We need to implement additional preventive measures in the postoperative period.