Risk factors associated with revision for prosthetic joint infection after knee replacement

As Erik Lenguerrand and colleagues

reported, 3659 of 679 010 primary total knee replacements (TKRs) were subsequently revised for an indication of prosthetic joint infection. The authors have identified several risk factors for revision for prosthetic joint infection and concluded that some of these factors are modifiable, and the use of targeted interventions or strategies could lead to a reduced risk of revision for prosthetic joint infection.

However, we noted that there were two factors that require further study. First, operation under general anaesthesia (rate ratio [RR] 1·1, 95% CI 1·0–1·2) was associated with a higher risk of revision for prosthetic joint infection. This study

is the first to propose that general anaesthesia will increase the incidence of infection after total knee arthroplasty. However, the authors did not study prophylactic use of antibiotics during general anaesthesia, which might influence the effect of general anaesthesia to TKR.

Second, use of posterior-stabilised fixed-bearing prostheses (RR for posterior-stabilised fixed-bearing prostheses vs unconstrained fixed-bearing prostheses 1·4, 1·3–1·5) was associated with a higher risk of revision for prosthetic joint infection. However, the authors did not assess the use of antibiotic cement for prosthetic fixation in their research. A previous study has shown that non-antibiotic cement could lead to an increase in the rate of infection after TKR (adjusted hazard ratio 1·35, 95% CI 1·01–1·81).

The different cement might influence the survival for different kinds of prostheses.

In summary, the conclusion that general anaesthesia and posterior-stabilised fixed-bearing prostheses increase the risk of infection requires further investigation.