IPC & NSQIP Surgical Site Infection Rates Not Comparable For Total Hip & Total Knee Replacements

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Using data collected on total hip replacements and total knee replacements in Alberta, a recent quality improvement study found significant variation in the post-operative surgical site infection (SSI) rates reported within two different quality monitoring programs in the province. The study uncovered that SSI results reported were not comparable between the two programs.

Alberta Health Services (AHS) Infection Prevention and Control (IPC) works in partnership with the Alberta Bone and Joint Health Institute to perform population-level surveillance for SSIs related to all primary total hip and total knee replacement surgeries performed in thirteen acute care facilities in the province.

Simultaneously, the National Surgical Quality Improvement Program (NSQIP) from the American College of Surgeons is becoming more commonplace as a measurement tool. AHS began using NSQIP in 2015 for multiple surgery types at four hospitals; this has since expanded to sixteen hospitals (14 adult and 2 pediatric). NSQIP uses a proprietary sampling strategy to monitor several quality indicators, including SSI.

The study took an in-depth look at the SSI rates for primary total hip and total knee replacement surgeries reported between 2015 and 2018 within the two programs. The authors acknowledge that IPC and NSQIP are both importantly guiding quality improvement aimed at improving patient outcomes. However, effective quality monitoring programs often have implications for workflow processes and resource allocation within a health system.

“The differences between IPC and NSQIP in the reported SSI rates for hip and knee replacements need to be emphasized to clinical teams and health administrators to best support the interpretation of the results. The two programs use different case finding methods, and NSQIP reported rates that were consistently higher than IPC for complex infections,” said the authors. “Of note, differences in the SSI trending pattern were observed as well. These findings are highly relevant if stakeholders were to invest major resources into quality improvement initiatives and, hence, a consistent approach to monitoring for complex SSIs would be desirable”. The publication acknowledges limitations within the study methodology, noting that future work should investigate other surgeries and larger databases.


Ellison, J., Boychuk, L., Chakravorty, D., Chandran, A., Conly, J., Howatt, A., . . . Bush, K. (2021). A comparison of surgical site infections following total hip replacement and total knee replacement surgeries identified by Infection Prevention and Control and the National Surgical Quality Improvement Program in Alberta, Canada. Infection Control & Hospital Epidemiology, 1-7. doi:10.1017/ice.2021.159