Improving physical activity after knee replacement surgery

Knee Arthroplasty Activity Trial

Not applicable Interventional Brigham and Women's Hospital · NCT04107649

This study is testing different ways to help people who have had knee replacement surgery be more active, including using an activity tracker and getting coaching, to see which method works best.

Quick facts

PhaseNot applicable
Study typeInterventional
Enrollment600 (estimated)
Ages40 Years to 85 Years
SexAll
SponsorBrigham and Women's Hospital Academic / other
Locations5 sites (Chicago, Illinois and 4 other locations)
Trial IDNCT04107649 on ClinicalTrials.gov

What this trial studies

The Knee Arthroplasty Activity Trial (KArAT) is a randomized controlled trial aimed at enhancing physical activity levels in patients who have undergone total knee replacement (TKR) for knee osteoarthritis. Participants will be randomly assigned to one of three groups: standard post-operative care, standard care plus a wrist-based activity tracker, or standard care plus the tracker with additional telephonic coaching and financial incentives. The study seeks to evaluate the effectiveness and cost-effectiveness of these interventions in promoting sustained physical activity post-surgery. By leveraging behavioral science principles, the trial aims to improve quality of life and functional outcomes for TKR patients.

Who should consider this trial

Good fit: Ideal candidates are English-speaking individuals aged 40-85 scheduled for primary unilateral total knee replacement due to osteoarthritis.

Not a fit: Patients who are non-English speaking, reside in nursing homes, or have certain medical conditions like dementia or inflammatory arthritis may not benefit from this study.

Why it matters

Potential benefit: If successful, this trial could lead to improved physical activity levels and overall quality of life for patients recovering from knee replacement surgery.

How similar studies have performed: Other studies have shown promise in using behavioral interventions to enhance physical activity in post-operative patients, suggesting that this approach may be effective.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Age 40-85 years
* English-speaking
* Scheduled to undergo primary, unilateral total knee replacement (TKR) at one of the 4 recruitment centers
* OA is principal underlying indication for TKR
* During an accelerometer run-in period lasting one week at baseline (prior to surgery), subjects must show that they can comply with waist-worn physical activity tracker protocols by wearing the activity tracker for ≥4/7 days of the week for ≥10 hours/day
* Regular access to a personal computer, laptop, tablet, or smartphone for wrist-worn activity tracker syncing
* Satisfying average baseline steps/day criteria (calculated from waist-worn activity tracker data from the run-in period)

Exclusion Criteria:

* Non-English speaking
* Residence in nursing home
* Diagnosis of dementia, epilepsy, Parkinson's Disease, or diabetes with peripheral neuropathy
* Inflammatory arthritis (rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, reactive arthritis, systemic lupus erythematosus, polymyalgia)
* Psychological issues that preclude participation
* Inpatient or other musculoskeletal surgery scheduled within six months following index primary TKR
* Uses a wheelchair to ambulate (subjects who use a cane will be eligible)
* Surgeon-documented other reason for study exclusion
* Subject does not have regular access to a device capable of receiving email or text messages

Where this trial is running

Chicago, Illinois and 4 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Knee OsteoarthritisTotal Knee ReplacementPhysical Activity
Last reviewed 2026-06-09 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.