P08 – Global Burden of Surgical Site Infections (SSIs) Associated with Knee Arthroplasty

Author(s):
Holly Yu, Harshila Patel, Hanane Khoury, Sharon Welner, Pfizer

Background: SSIs are post-surgical complications, comprising the third most frequent nosocomial infection (generally 15% of total). S. aureus is the major cause of SSIs worldwide, with a particular increase in methicillin-resistant S. aureus (MRSA) prevalence in the past decade. Patients who undergo knee arthroplasty are among those susceptible of developing SSIs.

Hypothesis: To review the global epidemiology, mortality, costs and healthcare resource utilization of SSIs following knee arthroplasty.

Methods: A comprehensive search was conducted in PubMed and of relevant conference proceedings; 236 full-text publications were reviewed to identify the epidemiology and burden of SSIs related to knee arthroplasty published from 2003 to 2013.

Results: Median SSI infection rate (as percentage of all knee arthroplasty procedures) was 1.35% (range: 0.3%- 19%). Median 39% (27%-71%) of SSIs after knee arthroplasty were attributed to S. aureus. MRSA infection rates (as percentage of all S. aureus infections) vary widely by region, ranging from 1.2% to 47%; the lowest value was reported for Sweden, a country with usually low MRSA infection rates. Few studies evaluated mortality, resource utilization and costs due to SSIs associated with knee arthroplasty; however, differences in studies, populations and outcome measures precluded group analysis. SSI mortality rates following knee arthroplasty were reported by a UK study as 0.4 deaths per 100 procedures and by a US study as a 6-month rate of 29%. A US study (2007-2011) reported that within 1 year after primary total knee arthroplasty, patients with periprosthetic infection had on average 3.6 readmissions as compared to 0.1 readmissions for controls. It also reported a mean annual cost of $116,383 per patient with infection, over 4 times higher than matched controls.

Conclusions: Despite gaps in the literature, including insufficient data from South America, Asia and Africa, and inconsistent use of outcome measures, evidence to date indicates marked variation in SSI infection rates after knee arthroplasty that result in significant healthcare resource utilization and increased costs. Since the majority of these SSIs are attributed to S. aureus, it may be a worthwhile target for preventive strategies.