Polymicrobial prosthetic joint infections: risk factors and outcome.
Limited data are available regarding the risk factors and outcome of polymicrobial prosthetic joint infection (PJIs) when compared with monomicrobial PJI. Between January 1998 and November 2006, we retrospectively identified 34 of 174 prosthetic joint infections (19%) were polymicrobial. The 2-year cumulative probability of success of treating polymicrobial and monomicrobial PJIs was 63.8% and 72.8%, respectively. Twenty-six percent, 38%, and 29% of PJIs were treated with two-stage exchange, débridement and retention, or resection arthroplasty, respectively, and the 2-year survival rate free of treatment failure in each group was 77.7% (95% confidence interval, 42.8%-94.2%), 52.7% (95% confidence interval, 28.4%-75.9%), and 64.2% (95% confidence interval, 28.7%-88.9%). Methicillin-resistant Staphylococcus aureus (26.4% versus 7.1%) and anaerobes (11.7% versus 2.8%) were more common in polymicrobial PJIs. Polymicrobial PJIs occurred in patients with a soft tissue defect/dehiscence (23.5% versus 2.8%), drainage (79.4% versus 39.2%), or prior local irradiation (8.8% versus 0.71%). We found the following factors associated with polymicrobial prosthetic joint infections: the presence of a soft tissue defect/wound dehiscence (odds ratio, 5.9), drainage (odds ratio, 5.0), and age 65 years or older (odds ratio, 2.8).


METHODS
Level III, prognostic study. See the Guidelines for Authors for a complete description of levels of evidence.
Marculescu
Camelia E
CE
Division of Infectious Diseases, Medical University of South Carolina, 100 Doughty Street, Suite 210, BA/IOP South, PO Box 250752, Charleston, SC 29425, USA. marcule@musc.edu
Cantey
J Robert
JR
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D019643:Arthroplasty, Replacement / Q000009:adverse effects*; D015331:Cohort Studies; D003646:Debridement; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D007595:Joint Prosthesis / Q000009:adverse effects*; D008297:Male; D008875:Middle Aged; D016459:Prosthesis-Related Infections / Q000175:diagnosis / Q000382:microbiology* / Q000628:therapy*; D012086:Reoperation; D012189:Retrospective Studies; D012307:Risk Factors; D016896:Treatment Outcome
D000900:Anti-Bacterial Agents