Accelerometry and Rehabilitation After Knee Replacement Study (ARK) (ARK)

September 4, 2026 updated by: The Leeds Teaching Hospitals NHS Trust

Accelerometry and Rehabilitation After Knee Replacement Study (ARK): A Prospective, Randomised Controlled Trial.

Total knee replacement (TKR) is a successful and cost-effective treatment for end-stage arthritis. Its usage is increasing due to changing population demographics and quality of life (QoL) expectations. There were almost 100,000 total knee replacements (TKR) performed in England between 2018/19. After TKR, patient engagement in their rehabilitation exercises is very important but physiotherapy services are very stretched at present especially in the covid-19 era. Patient compliance with their exercises is poor at about 25%.

The use of wearable sensors (WS) following TKR is gaining lots of interest especially in the post covid-era. A recent review found five small studies which supported the feasibility of their use. WS may help with patients to engage better with their rehabilitation exercises after surgery, delivering remote physiotherapy and potentially help identify patients who may be struggling more and therefore need further targeted help with physiotherapy.

Sensors have the potential to be a cost-saving intervention for the NHS by improving efficiencies in monitoring patients by reducing number of outpatient appointments, reducing rehabilitation time, improving patient's adherence to rehabilitation schedules and increasing confidence in exercise regimes leading to improved health-related quality of life. We will conduct the first large scale study where 250 patients having TKR will be randomly chosen to either receive a WS (125 patients) against 125 patients who will have standard care (SC). Patient reported outcomes (PROMs), pain scores, objective measures of knee function and data from the sensors on how well patients engaged with their exercises will be collected. The study will also assess if WS is cost effective, at 6 months after surgery.

This study has the potential to revolutionise how pre- and post-knee replacement rehabilitation is delivered, providing an individualised, cost effective and successful solution to the current status.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Active, not recruiting

Conditions

Conditions

The disease, disorder, syndrome, illness, or injury that is being studied. On ClinicalTrials.gov, conditions may also include other health-related issues, such as lifespan, quality of life, and health risks.

Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Actual)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
250

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

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

Study Locations

  • United Kingdom
    • West Yorkshire
      • Leeds, West Yorkshire, United Kingdom, LS9 7TF
        • Leeds Teaching Hospitals NHS Trust

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

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

18 years to 100 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Study Population

  1. Operating lists will be screened by the clinical trials team to identify eligible patients and patient information sheets will be sent out with invitation to meet surgeon and confirm eligibility.
  2. Potentially eligible patients will be provided with a patient information sheet at their routine pre-operative outpatient clinic and their eligibility confirmed by their operating surgeon

Description

Inclusion Criteria:

  • • Primary total knee replacement patients

    • Participant is aged 18 years of age or over
    • Participant is able and willing to provide written informed consent
    • Participant with ability to work with smart devices
    • Participant having own device (Apple iPhone or iPad or Android tablet or smartphone - minimum requirement: IOS - 12.4 or later/Android - 6.5 or later)
    • Internet connection at patient's home - either Wifi or mobile internet (min. 3G)

Exclusion Criteria:

  • • Participants who are unwilling or mentally and/or physically unable to adhere to study procedures

    • Participants with dementia or other cognitive impairment which would prevent them from using the sensor/app
    • Presence of a previous joint replacement in the same knee
    • Surgical treatment of involved knee within the past 6 months (excluding arthroscopy)
    • Previous orthopaedic surgery for trauma or arthritis of the knee joint (such as a previous fracture fixation or osteotomy)
    • Active cancer (currently diagnosed and under treatment)
    • Unable to complete all trial procedures (e.g. attend follow up visits, complete questionnaires)
    • Unable to provide informed consent (cognitive disorder such as dementia, psychiatric illness)

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

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Placebo Comparator: Standard Care
Unsupervised home-based exercises following knee replacement
Other: Standard Care (in control arm)
Unsupervised home-based exercises following knee replacement
Experimental: Wearable Sensor
Remote monitoring of home-based exercises following knee replacement using a wearable sensor
Other: Remote monitoring of home-based exercises following knee replacement using a wearable sensor
Remote monitoring of home-based exercises following knee replacement using a wearable sensor

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Oxford Knee Score (OKS)
Time Frame: Completion of Patient satisfaction at 6 months (primary outcome), in addition to baseline, pre-operative, 6 weeks, 12 months after surgery
The Oxford Knee Score (OKS) is a 12-item, patient-reported outcome measure designed to assess pain and physical function in patients undergoing total knee replacement, with total scores ranging from 0 to 48, where higher scores represent better joint function and minimal pain.
Completion of Patient satisfaction at 6 months (primary outcome), in addition to baseline, pre-operative, 6 weeks, 12 months after surgery

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
Knee Injury & Osteoarthritis Outcomes Score (KOOS)
Time Frame: Baseline, 6 weeks, 6 months
The Knee Injury and Osteoarthritis Outcome Score (KOOS) is a 42-item, patient-reported instrument assessing short- and long-term knee injury outcomes across five subscales: Pain, Symptoms, Activities of Daily Living (ADL), Sport and Recreation Function, and Knee-Related Quality of Life (each scored 0-100, where 100 indicates no knee problems).
Baseline, 6 weeks, 6 months
Self-Administered Patient Satisfaction (SAPS)
Time Frame: 6 weeks, 6 months
The Self-Administered Patient Satisfaction (SAPS) scale is a 4-item, patient-reported instrument designed to measure overall satisfaction following orthopedic surgery, evaluating satisfaction with current symptoms, pain relief, ability to perform home/yard work, and ability to perform recreational activities, with scores ranging from 0 to 100 where higher scores indicate greater satisfaction.
6 weeks, 6 months
EQ-5D-5L
Time Frame: Baseline, 6 weeks, 6 months, 12 months
The EuroQol 5-Dimension 5-Level (EQ-5D-5L) is a standardized, patient-reported instrument measuring health-related quality of life across five dimensions-Mobility, Self-Care, Usual Activities, Pain/Discomfort, and Anxiety/Depression-each rated on 5 levels of severity, alongside a Visual Analogue Scale (EQ-VAS) measuring overall health from 0 to 100 (where 100 indicates the best imaginable health).
Baseline, 6 weeks, 6 months, 12 months
Wong-Baker FACES Pain Rating Scale (WB-FPRS)
Time Frame: Baseline, 6 weeks, 6 months
The Wong-Baker FACES Pain Rating Scale (WB-FPRS) is a patient-reported visual instrument that measures pain intensity using six drawn faces depicting progressive levels of distress, scored from 0 (no hurt) to 10 (hurts worst) in increments of two, where higher scores indicate greater pain severity.
Baseline, 6 weeks, 6 months
Goniometric range of motion (ROM)
Time Frame: Baseline, 6 weeks, 6 months
Goniometric range of motion (ROM) is an objective physical assessment measuring active and passive joint mobility in degrees using a standard goniometer, evaluating joint flexion and extension where higher degrees indicate greater range of motion.
Baseline, 6 weeks, 6 months
Timed Up and Go (TUG)
Time Frame: Baseline, pre-operative, 6 weeks, 6 months
The Timed Up and Go (TUG) test is an objective functional mobility and balance assessment that measures the time (in seconds) required for a participant to rise from a standard armchair, walk 3 meters, turn, walk back, and sit down, where shorter times indicate better functional mobility and physical performance.
Baseline, pre-operative, 6 weeks, 6 months

Collaborators and Investigators

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

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
The Leeds Teaching Hospitals NHS Trust

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)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 20, 2022

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
September 1, 2026

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
September 1, 2026

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
January 21, 2022

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
June 7, 2022

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 9, 2022

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
September 10, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
September 4, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • OR21/144310

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

IPD Plan Description

No ethical approval to share data

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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