Surgical Duration Increases the Risk of Infection Following Total Knee Arthroplasty

Abstract

Introduction: Risk stratification is used in total joint arthroplasty (TKA) to optimize outcomes and minimize complications. Modifiable risk factors such as surgical duration can be influenced by surgeons; however, under certain circumstances, prolonged surgery cannot be avoided. While previous studies have investigated the impact of surgical duration on post-operative complications, we felt that research was lacking in comparing both surgical duration and tourniquet time and the rate of infection following a TKA. Our learning objective was to investigate the risk of surgical site infections (SSIs) and periprosthetic joint infections (PJIs) from prolonged (1) surgical duration or (2) tourniquet time during primary TKAs. Materials and Methods: A multicenter health-care system database consisting of 15 hospitals was queried for all patients undergoing TKA between March 2020 and December 2020. Patient demographics, comorbidities, and infection data were collected. The surgical duration and tourniquet time were calculated for each patient undergoing a TKA and compared against the rate of PJI or SSI rate. PJI was defined based on the 2018 musculoskeletal infection society (MSIS) criteria, and superficial SSI was defined as any infection that did not meet MSIS criteria. Results: Of the 2511 patients who underwent primary TKA, 19 were found to have an infection. Average surgical duration of 126.17 min for patients with an infection compared to 103.44 min without infection (P = 0.02). There was a significantly increased infection rate with increased surgical duration after univariate analysis. Patients who developed any infection had an average tourniquet time of 78.5 min, whereas those without infections had an average of 62.14 min (P = 0.004). Infection rate began to increase once the surgical duration reached 70 min; however, the infection rate increase per 10-min increments was not statistically significant (P = 0.09). The infection rate began to increase at 50 min of tourniquet time and significantly increased as tourniquet time increased (P = 0.004). Conclusion: Surgical duration is associated with an increased risk of infection following TKA. Our study demonstrated tourniquet time had a greater impact on infection. There are many circumstances that lead to increased surgical and tourniquet duration, including increased body mass index, and severe deformity. Surgeons should consider deflating the tourniquet as soon as the critical parts of the surgery are complete to decrease the risk of post-operative infections. Keywords: Total knee replacement, infection, knee joint, tourniquets.