title: Burden of Surgical Site Infections Associated with Arthroplasty and the Contribution of Staphylococcus aureus.
abstract: BACKGROUND
  Patients undergoing arthroplasty are at considerable risk of experiencing post-operative complications, including surgical site infections (SSIs). In addition to potential economic consequences, SSIs can have a negative impact on patient outcomes and may potentially be life-threatening. Staphylococcus aureus has been consistently shown as the leading cause of SSIs associated with orthopedic surgery, with an important contribution from methicillin-resistant S. aureus (MRSA). This study evaluated the global burden of SSIs among patients undergoing orthopedic surgical procedures, and specifically those undergoing knee and hip arthroplasties.
  
  
  METHODS
  An extensive search of PubMed and recent conference proceedings was conducted. English articles published between 2003 and 2013 pertaining to SSI epidemiology, patient outcomes, and healthcare resource utilization and costs were reviewed.
  
  
  RESULTS
  Overall, 81 studies were included, mainly from North America and Europe. Median SSI and S. aureus SSI rates, calculated as percentage of all arthroplasty procedures, were 1.7% (range: 0.25%-4.4%; 15 studies) and 0.6% (range: 0.1%-23%), respectively. Median SSI rates were 1.3% (range: 0.05%-19%; 22 studies) after knee arthroplasty, and 2.1% (range: 0.05%-28%; 24 studies) after hip arthroplasty. S. aureus SSI rates ranged from 0.2%-2.4% and 0.18%-3.8% for patients undergoing knee and hip arthroplasty, respectively. The percentage of S. aureus SSIs because of MRSA varied widely within each patient category. SSI-related mortality data (14 studies) showed that in-hospital mortality rates were low (1.2%-2.5%), but increased with time after index arthroplasty procedure (up to 56% over 1 y). Studies assessing healthcare resource utilization (n = 21) revealed that developing post-orthopedic SSIs resulted in a two- to three-fold increase in length of hospital stay (LOS) compared with non-infected patients (median LOS: 18.9 d vs. 6 d for non-SSI patients). Patients with SSIs because of methicillin-resistant staphylococci incurred greater mean LOS compared with SSIs because of methicillin-sensitive organisms. Readmission rates reported in 11 studies indicate a greater likelihood in the presence of SSIs; comparison across studies was not feasible because of differences in data reporting. Consistent with increased healthcare resource utilization (LOS and readmission) associated with SSIs, cost studies (n = 23) revealed that the presence of SSIs was associated with up to three-fold cost increase compared with the absence of SSI across all orthopedic patient categories assessed.
  
  
  CONCLUSIONS
  SSIs are associated with increased morbidity, mortality rates, healthcare resource utilization, and costs. Despite the relatively low SSI incidence following orthopedic surgery and specifically arthroplasty, preventive methods, specifically those targeting S. aureus, would serve to minimize costs and improve patient outcomes.
authors.affiliation: 1 LASER Analytica , Montreal, Quebec, Canada .
authors.forename: Harshila
authors.initials: H
authors.lastname: Patel
authors.affiliation: 1 LASER Analytica , Montreal, Quebec, Canada .
authors.forename: Hanane
authors.initials: H
authors.lastname: Khoury
authors.affiliation: 2 Pfizer Inc. , Pearl River, New York.
authors.forename: Douglas
authors.initials: D
authors.lastname: Girgenti
authors.affiliation: 1 LASER Analytica , Montreal, Quebec, Canada .
authors.forename: Sharon
authors.initials: S
authors.lastname: Welner
authors.affiliation: 3 Pfizer Inc. , Collegeville, Pennsylvania.
authors.forename: Holly
authors.initials: H
authors.lastname: Yu
mesh_terms: D001178:Arthroplasty / Q000009:adverse effects*; D014943:Global Health; D017048:Health Care Costs; D006268:Health Facilities / Q000706:statistics & numerical data; D006801:Humans; D013203:Staphylococcal Infections / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D013211:Staphylococcus aureus / Q000302:isolation & purification*; D013530:Surgical Wound Infection / Q000453:epidemiology* / Q000382:microbiology / Q000401:mortality; D016019:Survival Analysis; D016896:Treatment Outcome