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Protocol for a prospective cohort study of assessing postoperative cognitive changes after total hip and knee arthroplasty in the Greater Toronto area
  1. Stephen Choi,
  2. Sinziana Avramescu,
  3. Beverley A Orser,
  4. Shelly Au
  1. Department of Anesthesiology, Sunnybrook Health Sciences Center, Toronto, Ontario, Canada
  1. Correspondence to Dr Stephen Choi; stephen.choi{at}


Introduction Cognitive changes after anaesthesia and surgery, such as delirium and postoperative cognitive dysfunction (POCD), are common and lead to poor outcomes and increased healthcare costs. While several interventions for delirium exist, there are no effective treatment strategies for POCD. Understanding the risks and contributing factors may offer clinicians unique opportunities to better identify and develop preventative interventions for those at higher risk. Elderly patients undergoing orthopaedic surgery are at high risk of developing postoperative delirium (PD) and POCD. The incidence of POCD has not been rigorously studied in the total hip and knee arthroplasty (THA/TKA) population. Therefore, we have designed a prospective, observational cohort study to assess POCD in patients undergoing THA/TKA, both increasingly common procedures. The incidence of PD and POCD in a high volume, tertiary care arthroplasty centre will be determined and associated risk factors will be identified.

Methods and analysis Cognitive function will be tested with a computer-based cognitive assessment tool [CogState Brief Battery], preoperatively at baseline and postoperatively while in hospital at (<3 days), 6 weeks and 4.5 months. The primary outcome is the incidence of postoperative cognitive decline at 4.5 months. Logistic regression analysis is planned to test the association of POCD with several potential risk factors. In addition, delirium will be assessed preoperatively and postoperatively in the hospital using the Confusion Assessment Method (3D-CAM).

Ethics and dissemination The protocol for this prospective observational study was approved by the Sunnybrook Health Sciences Centre Research Ethics Board (REB#: 040–2017). Recruitment commenced in May 2017 and will continue until 2019. The results will be disseminated in a peer-reviewed journal and in scientific meetings.

Trial registration number NCT03147937.

  • cognition
  • postoperative cognitive dysfunction
  • cognitive impairment
  • delirium

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  • Contributors SC designed study protocol, obtained funding, and is involved with study conduct, data analysis; SA obtained funding, and is involved with study conduct; BAO obtained funding; SA wrote first draft of manuscript, and is involved with study conduct. All authors edited and approved the final manuscript.

  • Funding This work is supported by the Sunnybrook Academic Health Sciences Centre Alternative Funding Plan Innovation Fund. The investigators received an in-kind donation for no cost access to the CBB from CogState Ltd. Funders have no role in the study design, data collection, management, analysis or interpretation of the data.

  • Disclaimer The views, statements and opinions presented in this work are solely the responsibility of the authors. CogState Limited did not have a role in the development of the protocol or analysis plan. Furthermore, they have no role in data analysis or dissemination of results.

  • Competing interests None declared.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Patient consent for publication Not required.

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