Antibiotic Cement
Limited evidence suggests the routine use of antibiotics in the cement does not reduce the risk of periprosthetic joint infections for patients undergoing cemented total knee arthroplasty (TKA).

Rationale

With respect to the use of antibiotic cement for knee arthroplasty surgery, one high quality randomized controlled trial (RCT) of 2968 primary total knee arthroplasty (TKA) patients showed no overall statisticallysignificant difference in infection rates, as well as no evidence for statistically significant reduction in infection rates involving infection with Stapylococcus aureus, Streptococcus species, Gram-negative bacilli or Propionibacterium/Cutibacterium organisms. A statistically significant difference was noted in rates of infection with coagulase-negative staphylococci for patients treated with Simplex P cement with erythromycin compare with non-antibiotic impregnated cement (Hinarejos, 2013). A moderate quality RCT of primary TKA using Simplex P with cefuroxime showed a reduction in deep infection rates with no significant difference in component loosening rates requiring revision (Chiu, 2002). A RCT of diabetic patients demonstrated no infections in forty-one patients where Simplex P cement and 2 g of cefuroxime was used when compared to 13.5% infection rate in 37 patients where Simplex P alone was used (Chiu et al 2001). Lastly, a RCT of knee revision patients demonstrated a statistically significant reduction in deep infection when Simplex P cement impregnated with vancomycin was compared to Simplex P cement alone, with no difference in component loosening (Chiu 2009).

Observational studies have shown conflicting results, with some studies demonstrating reduced odds of deep infection (Wu 2016), while others showed no difference or increased infection rates when antibiotic cement was used. (Dowsey, 2009; Namba, 2009; Taylor, 2016; Namba, 2009; Namba, 2013).


Most of the RCT evidence in favor of antibiotic cement comes from special populations (diabetics and revision patients) that are not widely applicable to the general primary TKA population, and the primary TKA studies do not support its use.

The importance of this recommendation regards the prevention of infection by using antibiotic cement as additional prophylaxis, which can have significant impact on patient function, and overall morbidity and health.

POSSIBLE HARMS OF IMPLEMENTATION
Indiscrimate use of antibiotic laden cement may have unintended consequences that were not specifically evaluated with this recommendation. Although the studies did not show increased risk of implant loosening, it is possible that cement with higher doses of antibiotics could increase risk of loosening by changing the mechanical properties of the cement fixation. Similarly, there is the potential for other effects such as antimicrobial resistance or increased costs to the healthcare system that should be considered.

FUTURE RESEARCH
Adequately powered randomized controlled trials assessing the impact of antibiotic cement on deep infection, implant survival and other patient outcomes are needed to determine which specific patient groups may benefit from this prophylactic treatment with total knee arthroplasty.