Potential Origins of Acute Surgical Site Infections in Non-Traumatic Orthopedic Surgery - a Single-Center Prospective Evaluation

Background: In orthopedic surgery, we overlook the proportion of surgical site infections (SSI) acquired Intra- versus postoperative. A better overview would help to allocate resources for infection control instead of solely aiming for the perioperative period. Methods: We make use of prospective our database composed of four prospective-randomized clinical interventional trials and surveillance registers and concentrate on acute SSIs. We evaluate each SSIs clinically by searching medical and nursing notes for potential postoperative events that could plausibly cause a postoperative acquisition of bacteria. Results: Among 370 cases, we estimated 241 SSIs (65%) to be acquired intraoperatively, and 129 (35%) postoperatively. There was a clear gradient from the shoulder to the (diabetic) foot, with the shoulder yielding the highest plausible part of intraoperative SSIs (93%) and the foot the least (29%). By excluding foot SSIs, the proportion of estimated intraoperative SSIs rose to 83% (204/242 cases). The three most frequent reasons for postoperative SSIs were wound debridement immediately preceding infection, skin breakdowns and local surgical complications of various reasons (hematoma, dehiscence), and necrosis with a high proportion of polymicrobial foot SSIs among the postoperative origins. In contrast, hematogenous SSIs were rare (3%) and intraoperative SSIs were more often due to skin commensals. Conclusions: According to our prospective clinical evaluation, one-third of acute orthopedic SSIs were related with a postoperative complication that could potentially be the cause of SSI. By excluding adult (diabetic) foot surgeries, this postoperative proportion is reduced to one-sixth. Aside from reviewing the initial surgical justifications in high-risk patients and promoting (hand) hygiene, we require additional preventative treatments for the initial postoperative period. Clinical Trial Numbers: NCT05502380, NCT04081792, NCT05647252, NCT04048304.