Overview

Knee osteoarthritis is a common, chronic degenerative condition that causes pain, functional limitations, and reduced quality of life, especially in adults older than 50 years. Although clinical practice guidelines recommend therapeutic exercise and physical therapy as the first-line treatment, many patients do not receive or adhere to the recommended programs. Digital health tools may help expand access and improve adherence by supporting home-based exercise.

This study is a parallel-group, randomized controlled clinical trial designed to evaluate the effectiveness of an artificial intelligence (AI)-assisted therapeutic exercise program delivered through a web-based app compared with a conventional home exercise program provided on paper in adults with knee osteoarthritis. The primary goal is to determine whether the AI-assisted program produces greater improvements in pain and knee-related function. Secondary goals include assessing changes in health-related quality of life and patient-perceived overall improvement, and comparing implementation outcomes like adherence, usability, satisfaction, self-efficacy for exercise, and use of the prescribed exercise resource (paper vs web platform). Participants will be recruited from the Department of Physical Medicine and Rehabilitation at Hospital Universitario 12 de Octubre and randomly assigned to either the AI-assisted exercise group or the conventional exercise group. The AI-assisted web app will adjust exercise dose and progression based on participant-reported pain and perceived exertion, using decision rules informed by clinical practice guidelines and high-quality research evidence. Both groups will complete a 6-week home-based exercise program and will also attend weekly in-person group sessions that will be held separately by study arm (experimental and control groups will not mix) to reduce cross-contamination and support masking procedures. These sessions will be used to address questions, reinforce the protocol, and monitor for adverse events. Clinical outcomes will include pain intensity (visual analog scale), knee-related disability and function (WOMAC), health-related quality of life (EQ-5D), and patient global rating of change (GROC). Physical performance outcomes (30-second Chair Stand Test and Stair Climb Test) will be assessed at baseline and 1 week after completion of the 6-week intervention. Assessments will be conducted at baseline, one week after the 6-week intervention, and at 3 and 6 months after the intervention, with the exception of physical performance outcomes, which will be assessed at baseline and 1 week post-intervention.

Eligibility

Inclusion Criteria (based on National Institute for Health and Care Excellence (NICE) guidance):

• Clinical criteria for KOA: age ≥45 years, activity-related knee pain, and morning knee stiffness lasting ≤30 minutes.
• Knee pain for 3 months or longer.
• Knee pain on most days during the previous month.
• Overall knee pain intensity ≥4 on an 11-point Numerical Rating Scale (NRS; 0-10) during the previous week.
• Ownership of a smartphone and ability to use a mobile application.
• Internet access at home and/or via the mobile phone.
• Ability to provide informed consent, participate, and complete study assessments.

Exclusion Criteria:

• Having a planned knee arthroplasty (knee replacement) surgery.
• Knee prosthesis/arthroplasty in the most painful knee.
• Participation in a therapeutic exercise program for knee osteoarthritis within the past 6 weeks.
• Infiltration for knee osteoarthritis within the past 12 weeks.
• Inflammatory arthritic conditions.
• A fall in the past 12 months without medical clearance to perform unsupervised home exercise.
• Being homebound during the past month without medical clearance to perform unsupervised home exercise.
• Failing the pre-exercise screening and not having medical clearance to perform unsupervised home exercise.
• Inability to communicate in Spanish.
• Any neurological or systemic disease that may limit participation in the study.