886 - Impact of Type of Surgical Management on the Incidence of Recurrent Surgical Site Infections Following Hip and Knee replacements in Calgary, Alberta

Background: Recurrent surgical site infections (SSIs) are associated with decreased quality of life for patients and increased economic burden to healthcare systems. Positive cultures at reimplantation and patient co-morbidities have been shown to increase the risk of recurrent SSI in hip and knee surgical site infections. Two-stage exchange has been considered for the most appropriate surgical management for these SSI’s, however, it is unclear whether the type of revision arthroplasty and pathogen of the first SSI impacts recurrence rates.

Methods: A retrospective review of prospectively collected data on all complex SSIs following primary hip and knee arthroplasties between April 1 2012 and March 31, 2019, in Calgary, Alberta was performed. Patients were followed for two years post-index arthroplasty to determine initial management of first complex SSI (Debridement, antibiotics and implant retention (DAIR) vs DAIR+liner exchange vs one-stage vs two-stage), rate of recurrent complex SSI, and microbiological data for first and subsequent SSI’s.  

Results: Of the 142 complex SSIs, 95 (66.9%) were managed with DAIR and liner exchange, 25 (17.6%) were managed with DAIR, 13 (9.1%) with one-stage and 8 (5.6%) with two-stage procedures. The recurrence rate was 19/95 (20%)  for DAIR and liner, 8/25 (32%) for DAIR alone, 2/13 (15%) with one stage, and 3/8 (37.5%) with two-stage. There was no significant difference in recurrence rates of complex SSI when stratified by surgical management. Of the pathogens, Staphylococcus aureus (S.aureus) (including methicillin-resistant S. aureus (MRSA)) accounted for 35.2% of total first SSI and 50% of recurrences. A significantly higher proportion of S.aureus infections (including MRSA) ended up with a recurrent infection compared to all other pathogens (p=0.045). Of the 32 recurrences, 28.1% were due to the same pathogen as the initial SSI.

Conclusion: S.aureus was the most common pathogen causing initial and recurrent SSIs. This reinforces that S.aureus complex SSIs would likely benefit from early recognition and aggressive treatment. Recurrence of SSI was not impacted by type of revision arthroplasty. This study is limited by a small sample size. These findings contribute to the paucity of literature in this area and suggest a need for expansion to larger populations.