Risk factors for periprosthetic joint infection in total knee arthroplasty

Purpose. To evaluate the incidence and risk factors of periprosthetic joint infection (PJI) in patients undergoing total knee arthroplasty (TKA) in a high-volume hospital. Methods. Records of 1133 primary TKAs were reviewed. Correlation between surgery volume and infection rate was determined. Risk factors for PJI were identified using case-control analysis of variables. TKAs performed between October 2012 and March 2013 without infection were used as controls. Results. Of 1133 TKAs, 8 (0.71%) PJI occurred. The organisms involved were Staphylococcus aureus (n=4), coagulase-negative staphylococci (n=2), Pseudomonas aeruginosa (n=1), and methicillin-resistant S aureus (n=1). In the 6-month period chosen as the control period, one (0.52%) out of 192 TKAs developed PJI. Hospital annual volume did not correlate with infection rate (p=0.766). Significant risk factors included young age, comorbidities such as diabetes, anaemia, thyroid disease, heart disease, lung disease, and long operating time. Six of the 8 patients with PJIs had at least one risk factor. However, the number of patients with infection was too small to have sufficient power. Conclusion. Comorbidities are a risk factor for PJI. Perioperative optimisation of comorbidities and the use of antibiotic-loaded cement in patients with severe comorbidities should be considered.