Knee Arthroplasty Activity Trial

NCT ID: NCT04107649

Last Updated: 2025-11-24

Basic Information

• Recruitment Status: ACTIVE_NOT_RECRUITING
• Clinical Phase: NA
• Total Enrollment: 600 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2023-04-27
• Study Completion Date: 2028-06-15

Brief Summary

Total knee replacement (TKR) is a common and costly procedure widely used to relieve pain and improve function in patients with symptomatic advanced knee osteoarthritis (OA). As of 2013, the annual incidence of TKR was over 680,000 surgeries and annual costs exceeded $11 billion. Growing evidence suggests that while pain and functional status improve following TKR, physical activity (PA) typically does not surpass pre-TKR levels. Engagement in PA can meaningfully improve quality of life (QoL), pain, and function. Given the large investment in TKR, the effectiveness and cost-effectiveness of TKR could be substantially increased if TKR recipients became more physically active.

The Knee Arthroplasty Activity Trial (KArAT) is a randomized controlled trial and participants will be randomly assigned to one of three arms. Participants across all arms will receive usual post-operative care for TKR surgery. Participants in the first arm will complete basic study activities, such as responding to surveys and attending two in-person clinic visits. Participants in the second arm will do the same and also receive a wrist-based physical activity tracker intervention. Participants in the third arm will receive a telephonic active coaching (motivational interviewing) and financial incentives (for reaching physical activity goals) (TAC(MI)+FI) based intervention, as well as a wrist-based physical activity tracker intervention. The second and third arms will be eligible to receive lottery-based financial rewards for wearing a wrist-worn activity tracker for twenty-four months during the study.

Detailed Description

The investigators have designed the KArAT trial with two specific aims. First, to conduct a parallel three-arm RCT to establish the efficacy and sustainability of the effect of personalized intervention built on the principles of behavioral science and behavioral economics in improving PA among sedentary people who have undergone TKR. Our second aim is to establish the cost-effectiveness and budget impact of TAC(MI)+FI to improve PA in persons who have undergone TKR.

The three arms will include:

Arm 1: Usual post-TKR care

Arm 2: Usual post-TKR care + Wrist-based physical activity tracker wear

Arm 3: Usual post-TKR care + Wrist-based physical activity tracker wear + Telephonic Active Coaching (Motivational Interviewing) + Financial Incentives (TAC(MI)+FI).

Conditions

Knee Osteoarthritis; Total Knee Replacement

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: PARALLEL
• Primary Study Purpose: TREATMENT
• Blinding Strategy: TRIPLE

Study Groups

Arm1

Participants in this arm receive usual post-operative care and complete all basic study activities, which include: attending 2 in-clinic visits at designated time-points, having regular check-in calls with study staff over the intervention period, wearing and returning waist-worn activity trackers at 5 time points over two years, and completing 6 study surveys.

Group Type: OTHER

Basic Study Activities

Intervention Type: OTHER

Basic study activities begin two-weeks before TKR and end approximately 24-months after TKR. Basic study activities include: two in-person visits at the local clinic site (2 weeks before TKR and 32-weeks after TKR), having check-in calls with study staff weekly from weeks 1-13 after surgery and every other week for weeks 14-31, completing 6 surveys, and wearing an ActiGraph activity tracker (waist-worn) for five one-week periods throughout the study (2-weeks before-TKR, 32-weeks post-TKR, one-year post-TKR, 18-months post-TKR, two-years post-TKR). All participants will be eligible to receive up to $235 for completing these activities over the course of two years.

Arm2

Participants in this arm receive usual post-operative care, complete all basic study activities (as described in arm 1) and receive the wrist-based activity tracker intervention.

Group Type: EXPERIMENTAL

Basic Study Activities

Intervention Type: OTHER

Basic study activities begin two-weeks before TKR and end approximately 24-months after TKR. Basic study activities include: two in-person visits at the local clinic site (2 weeks before TKR and 32-weeks after TKR), having check-in calls with study staff weekly from weeks 1-13 after surgery and every other week for weeks 14-31, completing 6 surveys, and wearing an ActiGraph activity tracker (waist-worn) for five one-week periods throughout the study (2-weeks before-TKR, 32-weeks post-TKR, one-year post-TKR, 18-months post-TKR, two-years post-TKR). All participants will be eligible to receive up to $235 for completing these activities over the course of two years.

Wrist based activity tracker wear

Intervention Type: BEHAVIORAL

Activity tracking data will be collected on a weekly basis. Participants who receive this intervention are eligible to be entered into a lottery to win one of two $25 rewards for every week they wear their wrist-based activity tracker \>10 hours for \>4/7 days a week, beginning 6-weeks after surgery.

Arm3

Participants in this arm receive usual post-operative care, complete all basic study activities (as described in arm 1), receive wrist-based activity tracker intervention, and receive the TAC(MI)+FI.

Group Type: EXPERIMENTAL

Basic Study Activities

Intervention Type: OTHER

Basic study activities begin two-weeks before TKR and end approximately 24-months after TKR. Basic study activities include: two in-person visits at the local clinic site (2 weeks before TKR and 32-weeks after TKR), having check-in calls with study staff weekly from weeks 1-13 after surgery and every other week for weeks 14-31, completing 6 surveys, and wearing an ActiGraph activity tracker (waist-worn) for five one-week periods throughout the study (2-weeks before-TKR, 32-weeks post-TKR, one-year post-TKR, 18-months post-TKR, two-years post-TKR). All participants will be eligible to receive up to $235 for completing these activities over the course of two years.

Telephonic Active Coaching (Motivational Interviewing) + Financial Incentives

Intervention Type: BEHAVIORAL

As part of TAC(MI)+FI, participants speak with a health coach at Brigham and Women's Hospital once a week via telephone for weeks 6-13 following surgery, and once every other week for weeks 14-31 after surgery. Participants in this arm can receive financial rewards for achieving weekly physical activity goals, as well as bonus rewards for achieving goals multiple weeks in a row. Over the course of this 6-month long TAC(MI)+FI intervention period, these participants are able to receive up to $680 for meeting physical activity goals, and up to $95 in bonus rewards.

Wrist based activity tracker wear

Intervention Type: BEHAVIORAL

Activity tracking data will be collected on a weekly basis. Participants who receive this intervention are eligible to be entered into a lottery to win one of two $25 rewards for every week they wear their wrist-based activity tracker \>10 hours for \>4/7 days a week, beginning 6-weeks after surgery.

Interventions

Basic Study Activities

Basic study activities begin two-weeks before TKR and end approximately 24-months after TKR. Basic study activities include: two in-person visits at the local clinic site (2 weeks before TKR and 32-weeks after TKR), having check-in calls with study staff weekly from weeks 1-13 after surgery and every other week for weeks 14-31, completing 6 surveys, and wearing an ActiGraph activity tracker (waist-worn) for five one-week periods throughout the study (2-weeks before-TKR, 32-weeks post-TKR, one-year post-TKR, 18-months post-TKR, two-years post-TKR). All participants will be eligible to receive up to $235 for completing these activities over the course of two years.

Intervention Type: OTHER

Telephonic Active Coaching (Motivational Interviewing) + Financial Incentives

As part of TAC(MI)+FI, participants speak with a health coach at Brigham and Women's Hospital once a week via telephone for weeks 6-13 following surgery, and once every other week for weeks 14-31 after surgery. Participants in this arm can receive financial rewards for achieving weekly physical activity goals, as well as bonus rewards for achieving goals multiple weeks in a row. Over the course of this 6-month long TAC(MI)+FI intervention period, these participants are able to receive up to $680 for meeting physical activity goals, and up to $95 in bonus rewards.

Intervention Type: BEHAVIORAL

Wrist based activity tracker wear

Activity tracking data will be collected on a weekly basis. Participants who receive this intervention are eligible to be entered into a lottery to win one of two $25 rewards for every week they wear their wrist-based activity tracker \>10 hours for \>4/7 days a week, beginning 6-weeks after surgery.

Intervention Type: BEHAVIORAL

Other Intervention Names

TAC(MI)+FI

Eligibility 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

• Minimum Eligible Age: 40 Years
• Maximum Eligible Age: 85 Years
• Eligible Sex: ALL
• Accepts Healthy Volunteers: No

Sponsors

Northwestern Memorial Hospital

OTHER

Sponsor Role: collaborator

University of Kansas Medical Center

OTHER

Sponsor Role: collaborator

University at Buffalo

OTHER

Sponsor Role: collaborator

University of Nebraska

OTHER

Sponsor Role: collaborator

Brigham and Women's Hospital

OTHER

Sponsor Role: lead

Responsible Party

Elena Losina

Co-Director of OrACORe, Robert W. Lovett Professor of Orthopaedic Surgery at Harvard Medical School

Responsibility Role: PRINCIPAL_INVESTIGATOR

Principal Investigators

Elena Losina, Ph.D.

Role: PRINCIPAL_INVESTIGATOR

Brigham and Women's Hospital

Locations

Northwestern Memorial Hospital

Chicago, Illinois, United States

University of Kansas Medical Center

Kansas City, Kansas, United States

Brigham and Women's Hospital

Boston, Massachusetts, United States

University of Nebraska Medical Center

Omaha, Nebraska, United States

University at Buffalo

Buffalo, New York, United States

Countries

United States

References

Losina E, Collins JE, Kumara M, Ehrlich-Jones L, Opare-Addo M, Safran-Norton C, Segal NA, Mitchell LM, Kopp PT, Selzer F, Mass H, Paskewicz M, Chang RW, Dunlop D, Chen AF, Lerner S, Chin S, Pellegrini C, Katz JN. KArAT (Knee Arthroplasty Activity Trial): Rationale and design features of a multicenter randomized controlled trial. Osteoarthr Cartil Open. 2024 Aug 23;7(2):100512. doi: 10.1016/j.ocarto.2024.100512. eCollection 2025 Jun.

Reference Type: DERIVED

PMID: 40276263 (View on PubMed)

Other Identifiers

2019P002700

Identifier Type: -

Identifier Source: org_study_id