Is the prognosis the same for periprosthetic joint infections due to Staphylococcus aureus versus coagulase-negative staphylococci? A retrospective study of 101 patients with 2-year minimum follow-up

Background

Staphylococcus aureus (SA) and Coagulase-negative staphylococci (CoNS) are often responsible for infections of total hip arthroplasty (THA) and total knee arthroplasty (TKA). One of the main differences between these two microorganisms is their virulence, with SA presumed to be more virulent; however, few studies have specifically investigated the impact of this virulence. This inspired us to carry out a retrospective study to evaluate whether the healing rate differed between SA and CoNS infections.

Hypothesis

We hypothesised that the healing rate is lower for SA prosthetic joint infections.

Materials and methods

This was a retrospective study of 101 consecutive Staphylococcus infection cases that occurred between 2007 and 2011. There were 56 men and 45 women with an average age of 69 years (range 23–95). The infection was associated with TKA in 38 cases and THA in 63 cases. Thirty-two percent of patients had one or more comorbidities with infectious potential. In our cohort, there were 32 SA infections (31.7 %) and 69 CoNS infections (68.3 %) with 58 of the infections being methicillin-resistant (15 SA and 43 CoNS); there were 27 polymicrobial infections (26.7 %).

Results

With a minimum 24-month follow-up after the end of antibiotic treatment, the healing rate was 70.3 % overall (71 patients). The healing rate was 75 % in the SA group (24 patients) versus 68.1 % (47 patients) in the CoNS group (P = 0.42).

Conclusion

Our hypothesis was not confirmed: the healing rate of SA prosthetic joint infections was not lower than that of CoNS infections.

Level of evidence

III, retrospective case–control study.