Prosthetic joint infections due to methicillin-resistant and methicillin-susceptible staphylococci treated with open debridement and retention of the prosthesis.

OBJECTIVES: To compare the specific characteristics, the outcome and the predictors of failure of prosthetic joint infections (PJI) due to methicillin-resistant (MRS) and methicillin- susceptible staphylococci (MSS) treated with open debridement and retention of the implant.

MATERIAL AND METHODS: PJI due to MRS or MRS prospectively registered in a database from 1999 to 2009 were retrospectively reviewed.

RESULTS: During the study period, 96 patients met the inclusion criteria of the study. The mean follow-up period was 3.9 years and at least 2 years in all patients. The failure rate was 25%. The only variable significantly associated with failure in the global cohort was polymicrobial infection (59.3% vs. 40.7%, p=0.036). Thirty-four (35.4%) patients had an infection due to MRS and 62 (63.6%) due to MSS. Among MSS infections, 95.2% corresponded to primary arthroplasties while 29.4% of PJI due to MRS were after revision arthroplasties (p=0.001). CRP was significantly higher in PJI due to MSS (5.2 mg/dl vs 9.1 mg/dL, p=0.02).The failure rate (20% vs 27%, p=0.62) was very similar in MSS and MRS groups.

CONCLUSION: PJI due to MRS were mainly coagulase-negative staphylococci, more frequent after revision arthroplasties, had a lower inflammatory response, and had a similar failure rate than MSS infections.