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Knee surgery longer than 100 minutes linked to increased risk of infection


One-hundred minutes is the threshold for total knee replacement surgery after which the risk of deep joint infection increases, often requiring subsequent additional surgery, according to researchers at ICES, a non-profit research institute that uses population-based health information to produce knowledge on a broad range of healthcare issues.

The study, released in the open-access journal, EClinicalMedicine published by The Lancet, looked at patients undergoing total knee replacement surgeries in Ontario, Canada, between 2009 and 2016 (7 years).

“Our findings show that operations longer than 100 minutes predicted an increased risk of deep infection requiring subsequent surgery. This threshold serves as a useful time-point for identifying patients who require closer surveillance,” says Dr. Bheeshma Ravi, lead author on the study, adjunct scientist at ICES and staff surgeon at Sunnybrook Health Sciences Centre.

Total knee arthroplasty (TKA) is one the most commonly performed elective procedures in the world, with more than 600,000 TKAs performed annually in North America.

In this study of 92,343 patients undergoing primary TKAs, the average surgery lasted 106 minutes. The researchers compared patients whose surgery was longer than 100 minutes to those whose surgery was under 100 minutes. The main findings showed the risk of deep infection requiring subsequent surgery was nearly double the rate for the longer surgeries compared to the shorter surgeries (1.1 per cent vs 0.6 per cent).

“Our findings mean the risk of deep infection starts relatively low, but noticeably increases at approximately 100 minutes,” adds Dr. Ravi. “These deep infections can lead to substantial disabilities in patients and are difficult to treat with antibiotics,” adds Dr. Donald Redelmeier who is a co-author of the research, senior scientist at ICES, and a general internist at Sunnybrook Health Sciences Centre.

The study “Surgical duration is associated with an increased risk of periprosthetic infection following total knee arthroplasty: a population-based retrospective cohort study,” was published by The Lancet in EClinicalMedicine.

Author block: Bheeshma Ravi, Richard Jenkinson, Sven O'Heireamhoin, Peter C. Austin, Suriya Aktar, Timothy Leroux, J. Michael Paterson and Donald A. Redelmeier.

ICES is an independent, non-profit research institute that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. In October 2018, the institute formerly known as the Institute for Clinical Evaluative Sciences formally adopted the initialism ICES as its official name. For the latest ICES news, follow us on Twitter: @ICESOntario


Deborah Creatura
Media Advisor, ICES
[email protected]
(o) 416-480-4780 or (c) 647-406-5996

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