Early Cognitive Changes After Same-day Discharge Hip and Knee Arthroplasty

June 17, 2026 updated by: Abdullahi Abdirisak Hirsi, Odense University Hospital

Early Cognitive Changes in Patients Aged 70 Years or Older After Same-day Discharge Hip and Knee Arthroplasty: A Prospective Cohort Study

The goal of this observational study is to explore early cognitive changes in patients aged 70 years or older undergoing same-day discharge after hip or knee replacement surgery. The main question it aims to answer is:

Does patients experience cognitive changes in cognitive test performance from before surgery to the first day after surgery?

Participants will:

  • Complete a cognitive test battery virtually about 14 days before surgery, and on the first and seventh day after their operation.
  • Record pain levels and pain medicine use during the first week after surgery

Study Overview

Status

Recruiting

Conditions

Detailed Description

Introduction Background Postoperative cognitive dysfunction (POCD) is a prevalent complication in elderly patients and has significant clinical and socioeconomic consequences, delayed recovery, decreased quality of life, persistent neurocognitive disorders and increased morbidity and mortality within the first year of surgery . The pathogenesis remains poorly understood, partly due to varying diagnostic approaches and methodologies. Nevertheless, there is consensus that POCD is multifactorial influenced by factors such as advanced age, sleep disturbances, and inadequate perioperative pain management .

Sleep deprivation, in particular, can exacerbate hyperalgesia, impair cognition, and lead to increased respiratory and cardiac risks due to REM sleep rebound. Fast-track surgical protocols, which emphasize multimodal rehabilitation-including regional anesthesia, opioid-sparing analgesia, and early mobilization-have been shown to reduce postoperative pain, sleep disturbances, and the risk of delirium. These protocols have reduced the average length of hospital stays worldwide. In Denmark length of hospital stay after total hip arthroplasty (THA), total knee arthroplasty (TKA) and unicompartmental knee (UKA) is now only one day and an increasing number of patients are discharged on the day of surgery. Same-day discharge enable earlier return to a familiar environment and potentially enhanced pathophysiological recovery.

No studies have described early postoperative cognitive test performance in elderly patients undergoing same-day discharge hip and knee arthroplasty. This study therefore aims to address this knowledge gap by examining early cognitive changes in patients aged ≥70 years after same-day discharge hip and knee arthroplasty.

Aim The primary aim of this study is to report early cognitive changes measured with Symbol Digit Modality Test (SDMT) in patients over 70 years undergoing same-day discharge THA, TKA and UKA. Secondary, to report cognitive changes using the Stroop Color Test and verbal fluency test as well as patient's perceived cognitive function. As patients return home on the day of surgery in this contemporary same-day discharge arthroplasty setting, we hypothesize that early postoperative changes in cognitive performance will be limited compared with earlier fast-track studies with a longer median length of stay (LOS).

Methods

The cognitive tests:

The cognitive tests will be administered by research assistants with prior research experience.

Eligible participants will be recruited from the outpatient clinic. Testing will be performed virtually with the patients being at home. The patients will receive instructions to complete all sessions in the same quiet room and on the same device, to keep environmental stimuli (lighting, background noise, screen distance, seating, posture, and internet conditions) constant and thereby reduce within-subject variance and practice effects. The baseline test will be administered 14 days +- 3 days prior to surgery to avoid preoperative anxiety effects. Postoperatively, testing will be carried out on postoperative day 1 and day 7. More frequent testing is avoided to reduce practice effects.

Only patients receiving spinal anesthesia will be included to minimize confounding from general anesthesia and to reflect current fast-track practice. Spinal anesthesia is administered using a relatively short-acting blockade bupivacaine 5 mg/mL, 2.5 mL (12.5 mg) in THA, while for primary TKA and UKA, bupivacaine 5 mg/mL, 2 mL (10 mg) . Standard local infiltration analgesia (LIA) will be used with 150 mL ropivacaine 2 mg/mL in knee arthroplasties but not in hip arthroplasties . Peripheral nerve blocks are not used. Patients will also receive cloxacillin 2 gr, methylprednisolone 125 mg and 1 gr tranexamic acid intravenously immediately prior to skin incision.

Postoperative pain management and other medication Postoperative pain management will follow a standardized multimodal, opioid-sparing regimen. All patients will receive paracetamol (1 g × 4) in combination with ibuprofen 400 mg × 3 (7 days) for THA patients in and 400 mg × 4 (14 days) for TKA and UKA patients, unless contraindicated.

Opioids will be reserved as rescue medication, administered only on an "as needed" basis. Morphine 10 mg tablets will be used as first-line rescue analgesia, with oxycodone 5 mg as an alternative for patients who do not tolerate morphine.

Data Source:

A REDCap database has been established in collaboration with the Open Patient Data Explorative Network (OPEN) at Odense University Hospital (25). Patients scheduled for hip and knee arthroplasty at Svendborg hospital and included in the planned study will be enrolled in the database following informed consent. Patient's baseline database will be registered on comorbidities and medication use entered by trained research staff.

Statistics and sample size Although this is an exploratory study, the sample size was guided by considerations from both the literature and our pilot planning. Because the design is paired, each participant serves as their own control (baseline vs. postoperative assessment). For the SDMT we assumed a minimal clinically important difference (MCID) of 4 points , a within-subject correlation of 0.85 between baseline and postoperative scores, and a standard deviation of 7.5 . With a two-sided alpha of 0.05 and 80% power, this corresponds to approximately 14 participants with complete paired measurements per subgroup (THA, TKA, and UKA) if analyses are performed separately. To account for anticipated dropout/non-same-day discharge, we will aim to enroll 16 patients per subgroup to obtain 14 participants with complete paired measurements.

Continuous variables will be summarized as mean with standard deviation (SD) and range if approximately normally distributed; otherwise as median with interquartile range (IQR) and range. Categorical variables will be described using absolute and relative frequencies (n, %).

Patient involvement Patients who have previously undergone hip or knee arthroplasty were involved in the design process. Their feedback informed the research questions and outcome measures, ensuring relevance and patient-centeredness. During pilot testing, participating patients also provided input on the planned assessment procedures and overall feasibility, which further informed methodological adjustments.

Study Type

Observational

Enrollment (Estimated)

48

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

  • Denmark
      • Svendborg, Denmark, 5700
        • Recruiting
        • Odense University Hospital, Svendborg Hospital
        • Contact:
        • Contact:
        • Principal Investigator:
          • Abdullahi Abdirisak Hirsi, MD

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Patients scheduled for hip or knee arthroplasty at Svendborg hospital, Denmark.

Description

Inclusion Criteria:

  • Unilateral elective primary Total Hip Arthroplasty, Total Knee Arthroplasty, or Unicompartmental Knee
  • Native Danish speaker
  • Spinal anesthesia

Exclusion Criteria:

  • Inability or unwillingness to provide informed consent
  • Inability to comply with virtual study procedures or follow-up sessions, including because of visual or hearing impairment
  • Known dementia or other diagnosed cognitive disorders or Brief Assessment of Impaired Cognition (BASIC)≤20
  • Parkinson's disease or other neurological conditions causing functional impairment
  • History of alcohol abuse (≥35 units per week)
  • Daily use of anxiolytics or hypnotics
  • Not discharged on the day of surgery

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Total Hip Arthroplasty
Patients aged 70 years or older undergoing elective unilateral total hip arthroplasty with planned discharge on the day of surgery.
Total Knee Arthroplasty
Patients aged 70 years or older undergoing elective unilateral total knee arthroplasty with planned discharge on the day of surgery.
Unicompartmental Knee Arthroplasty
Patients aged 70 years or older undergoing elective unilateral unicompartmental knee arthroplasty with planned discharge on the day of surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Symbol Digit Modalities Test (SDMT) score from baseline to postoperative day 1.
Time Frame: From baseline, 14 days before surgery, and postoperative day 1.
The SDMT is a validated neuropsychological tool that measures processing speed, attention, and visual scanning. The SDMT will be administered virtually as an oral 90-second test. The primary metric will be the SDMT score, defined as the number of correct digit substitutions completed within 90 seconds
From baseline, 14 days before surgery, and postoperative day 1.

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Stroop Color-Word Test score from baseline to postoperative day 1.
Time Frame: From baseline, 14 days before surgery, and postoperative day 1.
The Stroop Color-Word Test is a validated measure of selective attention and susceptibility to interference. The primary metrics will be completion time (seconds) and number of errors recorded for each session.
From baseline, 14 days before surgery, and postoperative day 1.
Change in Stroop Color-Word Test score from baseline to postoperative day 7.
Time Frame: From baseline, 14 days before surgery, and postoperative day 7.
The Stroop Color-Word Test is a validated measure of selective attention and susceptibility to interference. The primary metrics will be completion time (seconds) and number of errors recorded for each session.
From baseline, 14 days before surgery, and postoperative day 7.
Change in Verbal fluency assessment score from baseline to postoperative day 1.
Time Frame: From baseline, 14 days before surgery, and postoperative day 1.
Verbal fluency assessment is a validated test which assesses executive function, semantic memory, and language. In our test a semantic (animal naming) and a phonemic (letter S) fluency task were used, each administered for 60 seconds. Number of correct responses for each task will be registered.
From baseline, 14 days before surgery, and postoperative day 1.
Reporting patient-reported cognitive function on postoperative day 1.
Time Frame: Postoperative day 1.
A brief two-item subjective cognitive questionnaire will be administered to assess patient's perceived cognitive changes and to identify any discrepancy between subjective experience and objective neuropsychological test performance.
Postoperative day 1.
Change in Symbol Digit Modalities Test (SDMT) score from baseline to postoperative day 7.
Time Frame: From baseline, 14 days before surgery, and postoperative day 7.
The SDMT is a validated neuropsychological tool that measures processing speed, attention, and visual scanning. The SDMT will be administered virtually as an oral 90-second test. The primary metric will be the SDMT score, defined as the number of correct digit substitutions completed within 90 seconds
From baseline, 14 days before surgery, and postoperative day 7.
Change in Verbal fluency assessment score from baseline to postoperative day 7.
Time Frame: From baseline, 14 days before surgery, and postoperative day 7.
Verbal fluency assessment is a validated test which assesses executive function, semantic memory, and language. In our test a semantic (animal naming) and a phonemic (letter S) fluency task were used, each administered for 60 seconds. Number of correct responses for each task will be registered.
From baseline, 14 days before surgery, and postoperative day 7.
Change in patient-reported cognitive function from postoperative day 1 to postoperative day 7.
Time Frame: From postoperative day 1 and postoperative day 7.
A brief two-item subjective cognitive questionnaire will be administered to assess patient's perceived cognitive changes and to identify any discrepancy between subjective experience and objective neuropsychological test performance.
From postoperative day 1 and postoperative day 7.

Other Outcome Measures

Outcome Measure
Measure Description
Time Frame
Cumulative In-hospital postoperative morphine consumption
Time Frame: End of surgery until discharge from the hospital on the day 1 of surgery (DOS)
Measured in milligrams
End of surgery until discharge from the hospital on the day 1 of surgery (DOS)
Postoperative pain intensity during rest once a day.
Time Frame: From postoperative day 1 to postoperative day 7.
Patients will record pain intensity using an 11-point numeric rating scale (NRS, 0-10) in a pain diary.
From postoperative day 1 to postoperative day 7.
Postoperative pain intensity during activity once a day
Time Frame: From postoperative day 1 to postoperative day 7.
Patients will record pain intensity using an 11-point numeric rating scale (NRS, 0-10) in a pain diary. Pain will be assessed defined as a standardized 5-m walk test.
From postoperative day 1 to postoperative day 7.
Cumulative postoperative morphine consumption
Time Frame: Postoperative day 1 to postoperative day 7.
Measured in milligrams.
Postoperative day 1 to postoperative day 7.

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Odense University Hospital

Investigators

  • Principal Investigator: Martin Lindberg-Larsen, Professor, Head of Research / Consultant Orthopaedic Surgeon at Odense University Hospital. Department of Clinical Research, University of Southern Denmark (SDU)

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 18, 2026

Primary Completion (Estimated)

October 31, 2026

Study Completion (Estimated)

November 30, 2026

Study Registration Dates

First Submitted

May 14, 2026

First Submitted That Met QC Criteria

May 19, 2026

First Posted (Actual)

May 20, 2026

Study Record Updates

Last Update Posted (Actual)

June 22, 2026

Last Update Submitted That Met QC Criteria

June 17, 2026

Last Verified

June 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 25/49880

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

Individual participant data will not be publicly shared due to Danish data protection regulations and the nature of the clinical dataset. De-identified data may be made available from the investigators upon reasonable request and subject to applicable approvals.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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