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NCT Number: NCT05173064

Effects of a Machine Learning-based Lower Limb Exercise Training System for Knee Pain

The goal of the study is to confirm the idea of AI-powered Technological Surrogate Physiotherapist (TSP), by demonstrating its effectiveness and value as a new technology-based contribution to OA healthcare. Participants will be randomized to one of two groups: (1) the conventional PT group receiving the exercise program delivered through in-person sessions; or (2) the AI-guided group following the program through the TSP after an initial PT session. All individuals will take part in the study for 12 weeks, and data will be collected at baseline and 12 weeks after randomization.

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Key information

Age range

50 year and older

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

826, Haking Wong Building, Pokfulam, The University of Hong Kong, Hong Kong

Hong Kong, 000

Location contact

Kalun Or, Doctoral degree

CONTACT

[email protected]

(852) 3917-2587

Letong Li, Master degree

SUB_INVESTIGATOR

About this study

Knee pain, often caused by osteoarthritis, is a prevalent musculoskeletal disorder among older adults and significantly reduces physical function and quality of life. Exercise therapy has been shown to be an effective form of treatment for knee pain. However, the traditional delivery of exercise therapy requires that individuals attend clinics to participate in face-to-face exercise sessions, which can be expensive and inconvenient. In recent years, information technologies have been used to support the delivery of exercise programs. The programs have also shown great benefits in improving the management of knee pain. However, it remains a concern that physical therapists are not able to provide the patients with direct and immediate supervision when exercises are taken place remotely at home or in community centers, which can be detrimental to exercise performance and the management of knee pain.

Thus, the research team has developed a machine learning-based exercise training system to provide evidence-based lower limb exercise videos, real-time movement feedback, and tracking of exercise progress for older adults with knee pain. In this study, a 12-week randomized controlled non-inferiority trial will be conducted to compare the effects of the AI-powered Technological Surrogate Physiotherapist with those of in-person physiotherapy sessions.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • At least 50 years of age;
  • Report having knee pain most days of the week;
  • Has radiographic evidence of grade 2, 3, or 4 knee OA on the K-L scale in the posteroanterior and/or skyline view in at least 1 knee;
  • Willing and able, both physically and cognitively, to perform the exercises required in the study protocol;
  • Has normal or corrected-to-normal vision;
  • Able to speak Cantonese and read Chinese, AND
  • Able to provide written informed consent.

Exclusion criteria

  • Having a history of knee or hip replacement surgery;
  • Being nonambulatory;
  • Having systemic inflammatory arthritis (e.g., gout);
  • Having a history of trauma (e.g., fractures around the knee, dislocation, sprains or tears of soft tissues like ligaments) or surgical arthroscopy of either knee within the past 6 months;
  • Having intra-articular injection to the knee within the past 6 months;
  • Having cognitive impairment;
  • Involvement in a similar study (i.e., involving physical exercise or physical therapies for knee pain) within the past 6 months;
  • Undergoing recent or imminent surgery (within 3 months) , OR
  • Having medical co-morbidities that preclude participation in exercise.

Treatment and study plan

The AI-powered Technological Surrogate Physiotherapist

Device

The AI-powered Technological Surrogate Physiotherapist will have three key features:

  • Evidence-based exercise videos instructed by physical therapists
  • Real-time movement feedback and performance score
  • Exercise records.

Face-to-face physiotherapist-supervised exercise program

Behavioral

Physiotherapists will give usual face-to-face therapy. The assessment of participants' exercise movements will only be achieved in the traditional manner during face-to-face exercise sessions - by physiotherapists' visual inspection of and professional judgement on postural alignment and effectiveness, with verbal instructions for posture correction. The features of real-time movement feedback and tracking of exercise progress will not be provided.

Primary outcomes

  1. Changes in knee pain as assessed by a 11-point numerical pain rating scale as recommended by the OARSI

    Time frame: From baseline to 12 weeks

    0 represents no pain and 10 represents the worst possible pain.

  2. Changes in physical function as assessed by the Knee Injury and Osteoarthritis Outcome Score (KOOS) physical function sub-scale

    Time frame: From baseline to 12 weeks

    The scale regards the degree of difficulty in performing usual daily activities and higher level activities that involve physical function of the knee. Each item will be rated on a 5-point Likert scale ranging from 'None' (i.e., no difficulty) to 'Extreme' (i.e., extreme difficulty), based on which a normalized total score will be calculated (0 indicating extreme symptoms and 100 indicating no symptoms).

Secondary outcomes

  1. Changes in physical function as assessed by 30-second chair-stand test

    Time frame: From baseline to 12 weeks

    30-second chair stand test (30CST), which measures the number of stands the participant can complete in 30 sec, will be used to assess the general leg strength and functional performance.

  2. Changes in physical function as assessed by timed up-and-go test

    Time frame: From baseline to 12 weeks

    Timed up and go (TUG) test, which measures the time it takes the participant to standup from the chair, walk 3 meters, walk back to the chair, and sit down, will be used to assess functional mobility.

  3. Changes in physical function as assessed by maximal isometric strength of the quadriceps and hamstrings

    Time frame: From baseline to 12 weeks

    The participant will be instructed to maximally extend/flex each knee for 3 trials, 3 sec each, with a 1-minute rest in between. Verbal encouragement will be given in each trial to ensure the participant makes the maximum effort. The highest force of each muscle in the three trials will be used for data analysis.

    After each test trial, the severity of pain experienced by the participant during the trial will be assessed using the 11-point numerical pain rating scale.

  4. Exercise adherence

    Time frame: From baseline to 12 weeks

    Exercise adherence will be indicated by the proportion of sessions and proportion of exercises performed which will be recorded by the TSP system (only for intervention group) and by participants and researchers using a log book.

  5. Satisfaction with the therapeutic exercise training

    Time frame: From baseline to 12 weeks

    It will be rated by participants using a 7-point Likert scale with anchors of 'Extremely unsatisfied' and 'Extremely satisfied'.

  6. Convenience in terms of location and time for accessing the exercise therapy

    Time frame: From baseline to 12 weeks

    It will be assessed on an 11-point numerical rating scale, with 0 representing 'Extremely inconvenient' and 10 representing 'Extremely convenient'.

Study contacts

Contact information is provided by the study sponsor or research team.

Calvin Kalun Or, PhD

CONTACT

[email protected]

(852) 3917-2587

Sponsors and collaborators

Lead sponsor

The University of Hong Kong

Other

Registry information

Official study title

Development and Randomized Controlled Trial of an AI-powered Technological Surrogate Physiotherapist (TSP) Dedicated to Quality Enhancement and Cost Reduction in Knee Osteoarthritis Exercise Rehabilitation

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Dec 29, 2021
Registry last updated
Jun 4, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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