Self-managed vs Supervised Exercise for Knee OA (SELFIT)

A Cluster Randomized Trial in Patients With Knee Osteoarthritis Comparing Self-Managed Exercise in Fitness Centers With Physiotherapist-Supervised Exercise in Primary Care

Knee osteoarthritis (OA) is a common painful condition associated with pain and disability. OA healthcare costs the Danish society 4.6 billion DKK more per year than the non-OA population and we lack evidence on how best to organize and deliver care to reduce costs. Recommended first line treatment for knee OA is exercise with proven effects on symptoms. The current paradigm assumes that exercise needs to be delivered and supervised by a physiotherapist which require patients to attend a clinic at specific times and geographical locations. This is an expensive model of care and creates barriers for people that are active on the labor market or lives in remote areas with long distances to the nearest clinic. In fact, the productivity loss in Denmark associated with OA is estimated to be 12.4 billion DKK per year.

While effective on symptoms, the current model with supervised physiotherapy associates with significant shortcomings, and barriers related to patient heterogeneity, costs, accessibility, and work absenteeism.

As an alternative, a local fitness center is far more accessible as these are widely dispersed across the country, are accessible daily (including weekends) at all hours, is cheap and offers a wide variety of exercise types, classes, and equipment to accommodate individual preferences. The cost of a fitness center membership is approximately 300 DKK per month and includes exercise ad libitum. In contrast, a typical physiotherapist-supervised exercise program costs 3-4,000 DKK for a 2-month treatment with 2 weekly sessions.

Consequently, there is a need to investigate if self-managed exercise in a fitness center is cost-effective as first-line management of knee OA. To answer this question, the present trial aims to compare self-managed exercise in a fitness center to the current standard - supervised exercise. This has the potential to improve quality of care for people with knee OA by adding a cost-effective option for first line management of people with knee OA.

Study Overview

• Status: Not yet recruiting
• Conditions: Knee Osteoarthritis
• Intervention / Treatment: Behavioral: Self-managed exercise in a fitness center; Behavioral: Supervised Exercise

• Study Type: Interventional
• Enrollment (Estimated): 300
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Marius Henriksen, Professor; Phone Number: 0045 38164155; Email: Marius.Henriksen@regionh.dk
• Study Contact Backup: Name: Camilla P Paulsen, Phd student; Phone Number: 0045 24854096; Email: Camilla.paludan.paulsen@regionh.dk

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion criteria

• Diagnosis of knee OA according to the NICE criteria: Adults aged 45 or over with activity-related joint pain and either no morning joint-related stiffness or morning stiffness that lasts no longer than 30 minutes.

Exclusion criteria

• Completion of a supervised therapeutic exercise program for knee OA within 3 months
• Contraindication to exercise (e.g., resting systolic blood pressure > 200 or diastolic blood pressure >110 mmHg, acute or reoccurring chest pain, unstable angina. uncontrolled cardiac arrhythmias, decompensated heart failure. suspected or known dissecting aortic aneurysm)
• Lack of independent mobility that requires aid for transportation to/from exercise facilities.
• Any condition or impairment that, in the opinion of the recruiting GP, makes a potential participant unsuitable for participation or which may obstruct participation (e.g. psychiatric or cognitive disorders, language barriers, or opiate dependency).

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Self-managed exercise	Behavioral: Self-managed exercise in a fitness center; The participants are offered a 6-month membership of a local fitness club at no cost (paid by the trial). They will receive an introduction to the fitness centre and receive instructions from a personal trainer in the centre to create a personalized exercise programme
Active Comparator: Physiotherapist-supervised exercise	Behavioral: Supervised Exercise; The particiopants are offered participation in the usual care exercise delivered at municipal rehabilitation centers or private physiotherapy clinics, aat the discretion of the referring doctor.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain subscale of the KOOS (Knee injury and Osteoarthritis Outcome Score) questionnaire	Assessed by the Knee injury and Osteoarthritis Outcome Score (KOOS) pain subscale (patient-reported questionnaire). The KOOS pain subscale consists of 9 questions with a five-point Likert scale scoring system (ranging from 0 (least severe) to 4 (most severe)). The answers are summed and a 0-100 normalized score is calculated with 0 indicating extreme pain and 100 indicating no pain.	Change from baseline after 3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Health outcome and quality of life survey (EQ-5D-5L)	EQ-5D-5L is a standardized patient-reported instrument for use as a measure of health outcome and quality of life. EQ-5D-5L is designed for self-completion by respondents and is ideally suited for use in surveys.	Change from baseline after 3 months
Patient Global Assessment of disease impact (PGA)	Patient-reported degree of patient's perceived impact of their knee OA on their overall life will be obtained using a 100 mm analogue scale (VAS) with anchors: 0=" No impact" and 100 = "Worst imaginable impact".	Change from baseline after 3 months
KOOS Function subscale	Assessed by the Knee injury and Osteoarthritis Outcome Score (KOOS) physical function subscale (patient-reported questionnaire). The KOOS physical function subscale consists of 17 questions with a five-point Likert scale scoring system (ranging from 0 (least severe) to 4 (most severe)). The answers are summed and a 0-100 normalized score is calculated with 0 indicating extreme functional impairment and 100 indicating no functional impairment.	Change from baseline after 3 months
KOOS quality of Life (QOL) subscale	Assessed by the Knee injury and Osteoarthritis Outcome Score (KOOS) knee related quality of life subscale (patient-reported questionnaire) The KOOS knee related quality of life subscale consists of 4 questions with a five-point Likert scale scoring system (ranging from 0 (least severe) to 4 (most severe)). The answers are summed and a 0-100 normalized score is calculated with 0 indicating extremely poor knee related quality of life pain and 100 indicating very good knee related quality of life .	Change from baseline after 3 months
OMERACT-OARSI responder criteria	Number of treatment responders according to the OMERACT-OARSI response criteria. A participant is classified as a responder if at least 1of the following 2 conditions is observed: In either pain (KOOS pain subscale) or function (KOOS function subscale), a high improvement in the subscale, where high improvement in a subscale is achieved if there is both a >50% improvement from Baseline and an absolute change from Baseline of >20 points (0-100 scale), OR; Improvement in at least two of the following three:Improvement in pain (KOOS pain subscale) defined as >20% improvement from Baseline and an absolute change from Baseline of >10 points (0-100 scale).Improvement in function (KOOS function subscale) defined as >20% improvement from Baseline and an absolute change from Baseline of > 10 points (0-100 scale).Improvement in patient's global assessment defined as >20% improvement from Baseline and an absolute change from Baseline of >10 mm (0-100 scale).	3 months

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Analgesics usage	The participants' use of over-the-counter paracetamol and ibuprofen will be collected via questionnaire. Analgesics usage is recorded as a response to the questions "How often do you take pain relieving medicine* for your knee OA pain" with response options 1) Daily; 2) 2-3 times per week: 3) Rarer; or 4) Never. Responses 1 and 2 defines an analgesics user, whereas responses 3 and 4 defines a non-user. * A list of typical brand names will be provided.	After 1, 2, 3, 4, 5, 6 months
Sleep Quality Single-item sleep quality scale (SQS)	Sleep quality will be obtained with the global Single-item sleep quality scale (SQS).	After 1, 2, 3, 4, 5, 6 months
Self-reported physical activity (UCLA activity scale)	Self-reported physical activity will be obtained with the University of California Loas Angeles activity scale (UCLA). UCLA is a single-item 10-level-scale, ranging from level 10, representing a highly physically active patient, to level 1, a patient who is dependent on others and unable to leave home.	After 1, 2, 3, 4, 5, 6 months
Out of pocket spending on knee OA - The cost for patients questionnaire (CoPaQ)	The cost for patients questionnaire (CoPaQ) is a comprehensive tool to measure direct and indirect out-of-pocket costs of a health condition for patients and their families to various outpatient contexts.	After 1, 2, 3, 4, 5, 6 months
The World Health Organization Five Well-Being Index (WHO-5)	Self-reported mental well-being will be obtained with the WHO5-Well-Being Index consisting of five questions.	After 1, 2, 3, 4, 5, 6 months
Body weight	Is recorded as kilograms and obtained self-reported via questionnaire	After 1, 2, 3, 4, 5, 6 months
The KOOS (Knee injury and Osteoarthritis Outcome Score) questionnaire	The Knee injury and Osteoarthritis Outcome Score (KOOS) consists of 42 items covering five subscales (domains): 1) Pain; 2) Function; 3) Knee related quality of life; 4) Symptoms; 5) Sports and Recreation. The KOOS adopts a five-point Likert scale scoring system (ranging from 0 (least severe) to 4 (most severe)). A normalized score is calculated for each subscale (domain) with 100 indicating best score and 0 indicating the worst score.	After 1, 2, 3, 4, 5, 6 months
Health outcome and quality of life survey (EQ-5D-5L)	EQ-5D-5L is a standardized patient-reported instrument for use as a measure of health outcome and quality of life.	After 1, 2, 4, 5, 6 months
Patient Global Assessment of disease impact (PGA)	Patient-reported degree of patient's perceived impact of their knee OA on their overall life will be obtained using a 100 mm analogue scale (VAS) with anchors: 0=" No impact" and 100 = "Worst imaginable impact".	After 1, 2, 4, 5, 6 months
OMERACT-OARSI responder criteria	Number of treatment responders according to OMERACT-OARSI response criteria, following two conditions is observed at the post-baseline assessment: In either pain (KOOS pain subscale) or function (KOOS function subscale), a high improvement in the subscale, where high improvement in a subscale is achieved if there is both a > 50% improvement from Baseline and an absolute change from Baseline of > 20 points (0-100 scale), OR Improvement in at least two of the following three: Improvement in pain (KOOS pain subscale) defined as > 20% improvement from Baseline and an absolute change from Baseline of > 10 points (0-100 scale) Improvement in function (KOOS function subscale) defined as > 20% improvement from Baseline and an absolute change from Baseline of > 10 points (0-100 scale) Improvement in patient's global assessment defined as > 20% improvement from Baseline and an absolute change from Baseline of > 10 mm (0-100 scale)	After 6 months

Collaborators and Investigators

• Sponsor: Marius Henriksen
• Collaborators: University of Copenhagen; Research Unit for General Practice in Aalborg

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): December 31, 2027
• Study Completion (Estimated): December 31, 2027

Study Registration Dates

• First Submitted: September 30, 2025
• First Submitted That Met QC Criteria: September 30, 2025
• First Posted (Actual): October 7, 2025

Study Record Updates

• Last Update Posted (Actual): June 16, 2026
• Last Update Submitted That Met QC Criteria: June 15, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Keywords: Exercise
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Behavior; Osteoarthritis, Knee; Motor Activity
• Other Study ID Numbers: APPI-MSK-OA-SELFIT

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: We will share the IPD, protocol and SAP, but the circumstances and timing has not been decided yet
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No