Incidence of prosthetic joint infections after primary knee arthroplasty.

We report the 1-year incidence of postoperative infections in an unselected series of 2647 consecutive primary knee arthroplasties (3137 knees) performed in a modern specialized hospital dedicated solely to joint arthroplasty surgery in 2002 to 2006. The rates of superficial and prosthetic joint infections were 2.9% and 0.80%, respectively. Prospective surveillance by hospital infection register failed to detect 6 of the 24 prosthetic joint infections. Increased rate of prosthetic joint infections was associated with complex surgery and with several patient-related factors, for example, comorbidity, obesity, and poor preoperative clinical state. The rate of prosthetic joint infections in contemporary knee arthroplasty is low and mainly related to patient-related factors, of which patient comorbidity has the most profound effect on the infection rate.