The infected knee prosthesis

Deep infections are among the most severe complications in total knee arthroplasty; infection rates described in recent articles range between 1 and 2%. The most important infection risk prevention measures are skin preparation, antibiotic prophylaxis, and screening and management for methicillin-resistant Staphylococcus aureus (MRSA). Debridement and prosthesis preservation is indicated for acute postoperative infections or for acute hematogenous disseminations over well performing prostheses. The following criteria should be met for the result to be favorable: short delay from onset of symptoms (less than 2–3 weeks), Gram-positive germs, absence of prolonged wound drainage and presence of a stable implant. Two-stage replacement is currently the gold standard for treating chronic prosthetic knee infections. The survival rate free of implant removal for reinfection with this technique stands at 93% at 5 years and 85% at 10 years. Moreover, initial recovery figures are preserved with the passage of time. Survivorship free of implant removal for any reason is 90% at 5 years and 77% at 10 years. Articulated spacers seem to be better than static ones. Polymicrobial and Gram-negative infections can be controlled in late knee arthroplasty infections. On the other hand, infections by MRSA are less likely to be controlled by the standard regimens. Preoperative prophylactic antibiotics do not affect the results of intraoperative cultures and therefore they should not be withheld before surgery for an infected TKA when an organism has been identified on aspiration preoperatively, and there has been no recent (4 weeks) antimicrobial therapy.