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

Active, not recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Actual)

250

Phase

  • 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

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
Intervention / Treatment
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

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

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

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)

May 20, 2022

Primary Completion (Estimated)

September 1, 2026

Study Completion (Estimated)

September 1, 2026

Study Registration Dates

First Submitted

January 21, 2022

First Submitted That Met QC Criteria

June 7, 2022

First Posted (Actual)

June 9, 2022

Study Record Updates

Last Update Posted (Actual)

September 10, 2026

Last Update Submitted That Met QC Criteria

September 4, 2026

Last Verified

August 1, 2026

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID 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.

Subscribe