Abstract
Infection following primary total knee arthroplasty (TKA) is fortunately a relatively uncommon complication with an incidence of approximately 1%. However, because the morbidity and cost of treatment of deep prosthetic TKA infections is so high, effective prevention strategies are key quality improvement initiatives. The cause of post-operative infections are multifactorial and complex but can generally be categorised into 1) host, 2) surgical, and 3) environmental factors. The purpose of this abstract is to provide an outline of these factors and their influences on the infection risk following TKA.
Patient factors and optimization of modifiable risk factors have been shown to decrease the risk for infection. While the individual contributions of factors such as body mass index (BMI), diabetes, nutritional status, Charlson Comorbidity Index (CCI), and renal disease are unknown, together, they have been shown to influence infection risk. Additionally, Tayton et al. analyzed 64,566 primary TKAs in the New Zealand Joint Registry and found that male gender and prior knee surgery were also independent risk factors of development of PJI 12 months following TKA. Finally, Crowe and colleagues also identified tobacco use and Staphylococcus aureus colonization as modifiable risk factors for minimizing PJI following primary TKA.
Timely administration of prophylactic antibiotics prior and after surgery has been shown to be the most effective strategy to reduce infection risk. The optimal prophylaxis regimen for all patients is unknown and in certain situations, administration of Vancomycin in additional to a conventional cephalosporin may be beneficial. However, universal administration of Vancomycin has not been shown to decrease the incidence of surgical site infections and could actually increase the risk for renal failure. Conversely, addition of antibiotics to cement during primary TKA has not been shown to reduce long term infection risk. The use of dilute betadine lavage has been shown by some authors to be beneficial. Finally, good surgical technique, proper soft tissue handling, and meticulous wound closure are all critical factors influencing the risk for infectious complications following TKA.
Environmental factors have also been shown to affect infection rates following TKA. While the use of laminar flow and body exhaust suits have not been shown to significantly influence the risk for infection, minimizing operating room traffic has been shown effective in reducing the risk for contamination. Some authors have shown ultraviolet light systems to decrease airborne contaminants.
In summary, factors influencing infection risk following TKA are complex and multifactorial. Patient selection, optimization of modifiable risk factors, appropriate use of antibiotics, and minimization of OR traffic are among the most common strategies to minimizing infection.
