Prospective Cohort Study Evaluating a Thermal Spa Programme in Symptomatic Knee Osteoarthritis (THERMOG)

Prospective Cohort Study Evaluating a Thermal Spa Programme for the Management of Symptomatic Knee Osteoarthritis

This study evaluates the effects of a 3-week thermal spa treatment on knee joint movement in patients with knee osteoarthritis. Knee movement fluidity and gait parameters will be analyzed during standardized tasks using wearable inertial sensors (Xsens). Secondary outcomes include changes in pain, physical function, physical activity, quality of life, and blood transcriptomic profiles. Assessments will be performed at baseline, after treatment, and at 3- and 12-month follow-up visits.

Study Overview

• Status: Not yet recruiting
• Conditions: Gonarthrosis
• Intervention / Treatment: Device: X-sens sensor; Other: Transcriptomic; Other: Self-questionnaire

Detailed Description

Knee osteoarthritis is a common cause of pain, functional limitation, and reduced quality of life in older adults. Thermal spa treatment is widely used as a non-pharmacological intervention for the management of osteoarthritis symptoms, but its effects on joint movement and motor control remain insufficiently characterized using objective biomechanical measures.

This study aims to evaluate the effects of a 3-week thermal spa treatment on knee joint movement in patients with knee osteoarthritis. Movement analysis will be performed using wearable inertial sensors (Xsens) placed on the lower limbs to quantify kinematic and spatiotemporal gait parameters during standardized functional tasks. The primary outcome will assess changes in knee movement fluidity during walking, quantified using normalized angular jerk in the sagittal plane.

Secondary outcomes will include changes in pain intensity, osteoarthritis symptoms, physical activity level, and health-related quality of life assessed using validated questionnaires. In addition, blood samples will be collected before and after the intervention to explore transcriptomic changes associated with the treatment. Assessments will be conducted at baseline, immediately after the spa treatment, and during follow-up visits at 3 and 12 months.

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

Contacts and Locations

• Study Contact: Name: Yves-Marie PERS, MD; Phone Number: 33 04 67 33 80 74; Email: ym-pers@chu-montpellier.fr
• Study Contact Backup: Name: Hugues DESFOUR, MD; Phone Number: 33 0467485063; Email: Hugues.DESFOUR@thermesbalaruc.com

Study Locations

• France
  • Balaruc-les-Bains, France
    • Centre thermal de Balaruc les Bains
    • Contact: Hugues DESFOUR, MD; Phone Number: 33 04 67 33 80 74; Email: Hugues.DESFOUR@thermesbalaruc.com

Participation Criteria

Eligibility Criteria

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

Description

Inclusion Criteria:

• Adults aged 50 years or older
• Diagnosis of knee osteoarthritis affecting at least one knee, with radiographic Kellgren-Lawrence grade ≥ 2 confirmed by an X-ray performed within the past 3 years
• Average knee pain intensity > 30 mm on a 100-mm Visual Analog Scale (VAS) during the month prior to inclusion
• Participants scheduled to undergo a 3-week thermal spa treatment at the Balaruc-les-Bains thermal center

Exclusion Criteria:

• Use of systemic or injectable corticosteroids within 1 month prior to inclusion
• Intra-articular injection of hyaluronic acid or platelet-rich plasma (PRP) within the 3 months prior to inclusion
• Active inflammatory joint disease (e.g., rheumatoid arthritis, spondyloarthritis, or crystal-induced arthropathies)
• Current major depressive episode or psychotic disorders
• Thermal spa treatment within the previous 6 months
• Inability to read or write
• Inability to complete follow-up for the entire study period (e.g., planned relocation, travel, professional commitments, or residence located more than 100 km from the study site)
• Lack of informed consent
• Pregnant or breastfeeding women
• Individuals under legal protection (guardianship or curatorship)
• Not affiliated with a national health insurance system
• Individuals under judicial protection (safeguard of justice)
• Participation in another clinical study with an ongoing exclusion period

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: N/A
• Interventional Model: Single Group Assignment
• Masking: None (Open Label)

Number of Arms

1

Arms and Interventions

Participant Group / Arm

Intervention / Treatment

Experimental: Evaluation of the benefits of spa treatment for osteoarthritis of the knees; Assessment of the benefits of spa treatment for osteoarthritis of the knees between the start and end of treatment and in the medium to long term (3 and 12 months after treatment)

Device: X-sens sensor; Participants will be equipped with an Xsens wearable motion capture system consisting of eight inertial sensors placed on the feet, shanks, thighs, pelvis, and trunk. Assessments will be conducted before and after the thermal spa treatment and at follow-up visits at 3 and 12 months. Participants will perform standardized functional tasks including level walking (four 20-m round trips), stair ascent and descent (five 15-cm steps), and a chair sit-to-stand task performed without using the hands. Each task, except walking, will be repeated five times. All measurements will be performed under the supervision of a healthcare professional or an adapted physical activity specialist, and movement data will be recorded continuously.; Other: Transcriptomic; Approximately 5 mL of blood will be collected from each participant before and after the thermal spa treatment using RNA-stabilizing tubes. Samples will be pseudonymized using a coded identifier. Total RNA will be extracted and analyzed using transcriptomic approaches (RNA sequencing) to assess gene expression changes associated with the intervention. Differential gene expression analyses will be performed, and selected results may be validated using RT-qPCR; Other: Self-questionnaire; Self-administered questionnaires will be completed at baseline, after the thermal spa treatment, and at 3- and 12-month follow-up visits. These include: pain intensity measured using a Visual Analog Scale (VAS); osteoarthritis symptoms assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC); physical activity level evaluated with the International Physical Activity Questionnaire - Short Form (IPAQ-SF); and health-related quality of life assessed using the 12-Item Short Form Health Survey (SF-12).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Comparison of fluidity of knee joint movement	Knee joint movement fluidity in the sagittal plane will be quantified using the normalized angular jerk derived from inertial motion capture sensors (Xsens) during walking. Higher normalized angular jerk values indicate reduced movement fluidity. The primary analysis will compare the normalized angular jerk between baseline and post-thermal spa treatment assessments.	Baseline to post-spa (Day 21)

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in pain intensity measured by Visual Analog Scale (VAS)	Pain intensity over the previous 48 hours measured using a 100-mm Visual Analog Scale (VAS). The VAS is a continuous scale ranging from 0 to 100 mm, where 0 represents no pain and 100 represents the worst imaginable pain. Higher scores indicate greater pain severity. The outcome measure corresponds to the change in VAS score from baseline to follow-up assessments.	Baseline to post-spa (Day 21)
Change in pain intensity measured by Visual Analog Scale (VAS)	Pain intensity over the previous 48 hours measured using a 100-mm Visual Analog Scale (VAS). The VAS is a continuous scale ranging from 0 to 100 mm, where 0 represents no pain and 100 represents the worst imaginable pain. Higher scores indicate greater pain severity. The outcome measure corresponds to the change in VAS score from baseline to follow-up assessments.	Baseline to 3 months post-spa
Change in pain intensity measured by Visual Analog Scale (VAS)	Pain intensity over the previous 48 hours measured using a 100-mm Visual Analog Scale (VAS). The VAS is a continuous scale ranging from 0 to 100 mm, where 0 represents no pain and 100 represents the worst imaginable pain. Higher scores indicate greater pain severity. The outcome measure corresponds to the change in VAS score from baseline to follow-up assessments.	Baseline to 12 months post-spa
Change in osteoarthritis symptoms measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)	Osteoarthritis symptoms assessed using the WOMAC questionnaire including the total score and subscales : (pain, stiffness, and physical function). Scores range from 0 to 100, where 0 represents no symptoms and 100 represents maximum pain, stiffness, and functional limitation. Higher scores indicate worse clinical status. The outcome measure corresponds to changes in WOMAC scores from baseline to follow-up assessments.	Baseline to post-spa (Day 21)
Change in osteoarthritis symptoms measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)	Osteoarthritis symptoms assessed using the WOMAC questionnaire including the total score and subscales : (pain, stiffness, and physical function). Scores range from 0 to 100, where 0 represents no symptoms and 100 represents maximum pain, stiffness, and functional limitation. Higher scores indicate worse clinical status. The outcome measure corresponds to changes in WOMAC scores from baseline to follow-up assessments.	Baseline to 3 months post-spa
Change in osteoarthritis symptoms measured by the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC)	Osteoarthritis symptoms assessed using the WOMAC questionnaire including the total score and subscales : (pain, stiffness, and physical function). Scores range from 0 to 100, where 0 represents no symptoms and 100 represents maximum pain, stiffness, and functional limitation. Higher scores indicate worse clinical status. The outcome measure corresponds to changes in WOMAC scores from baseline to follow-up assessments.	Baseline to 12 months post-spa
Change in physical activity level measured by the International Physical Activity Questionnaire - Short Form (IPAQ-SF)	Physical activity level assessed using the IPAQ-SF questionnaire and expressed in MET-minutes per week. Higher values indicate higher levels of physical activity. The outcome measure corresponds to changes in physical activity level from baseline to follow-up assessments.	Baseline to post-spa (Day 21)
Change in physical activity level measured by the International Physical Activity Questionnaire - Short Form (IPAQ-SF)	Physical activity level assessed using the IPAQ-SF questionnaire and expressed in MET-minutes per week. Higher values indicate higher levels of physical activity. The outcome measure corresponds to changes in physical activity level from baseline to follow-up assessments.	Baseline to 3 months post-spa
Change in physical activity level measured by the International Physical Activity Questionnaire - Short Form (IPAQ-SF)	Physical activity level assessed using the IPAQ-SF questionnaire and expressed in MET-minutes per week. Higher values indicate higher levels of physical activity. The outcome measure corresponds to changes in physical activity level from baseline to follow-up assessments.	Baseline to 12 months post-spa
Change in health-related quality of life measured by the 12-Item Short Form Health Survey (SF-12)	Health-related quality of life assessed using the SF-12 questionnaire. Scores range from 0 to 100, with higher scores indicating better health-related quality of life. The outcome measure corresponds to changes in SF-12 scores from baseline to follow-up assessments.	Baseline to post-spa (Day 21)
Change in health-related quality of life measured by the 12-Item Short Form Health Survey (SF-12)	Health-related quality of life assessed using the SF-12 questionnaire. Scores range from 0 to 100, with higher scores indicating better health-related quality of life. The outcome measure corresponds to changes in SF-12 scores from baseline to follow-up assessments.	Baseline to 3 months post-spa
Change in health-related quality of life measured by the 12-Item Short Form Health Survey (SF-12)	Health-related quality of life assessed using the SF-12 questionnaire. Scores range from 0 to 100, with higher scores indicating better health-related quality of life. The outcome measure corresponds to changes in SF-12 scores from baseline to follow-up assessments.	Baseline to 12 months post-spa
Change in gait spatiotemporal and kinematic parameters	Spatiotemporal and kinematic gait parameters measured using wearable inertial sensors during standardized walking tasks. The outcome measure corresponds to changes in gait parameters between baseline and follow-up assessments.	Baseline to post-spa (Day 21)
Change in gait spatiotemporal and kinematic parameters	Spatiotemporal and kinematic gait parameters measured using wearable inertial sensors during standardized walking tasks. The outcome measure corresponds to changes in gait parameters between baseline and follow-up assessments.	Baseline to 3 months post-spa
Change in gait spatiotemporal and kinematic parameters	Spatiotemporal and kinematic gait parameters measured using wearable inertial sensors during standardized walking tasks. The outcome measure corresponds to changes in gait parameters between baseline and follow-up assessments.	Baseline to 12 months post-spa
Differential gene expression in blood transcriptome	Differential gene expression in blood samples analyzed using transcriptomic approaches to identify genes modulated by the intervention. Gene expression profiles will be compared between baseline and post-treatment assessments.	Baseline to post-spa (Day 21)

Collaborators and Investigators

• Sponsor: University Hospital, Montpellier
• Collaborators: Centre thermal de Balaruc les Bains
• Investigators: Study Director: Yves-Marie PERS, MD, University Hospital, Montpellier; Principal Investigator: Hugues DESFOUR, MD, University Hospital, Montpellier

Study record dates

Study Major Dates

• Study Start (Estimated): July 1, 2026
• Primary Completion (Estimated): August 1, 2028
• Study Completion (Estimated): July 1, 2029

Study Registration Dates

• First Submitted: April 9, 2026
• First Submitted That Met QC Criteria: April 9, 2026
• First Posted (Actual): April 16, 2026

Study Record Updates

• Last Update Posted (Actual): April 16, 2026
• Last Update Submitted That Met QC Criteria: April 9, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: Knee osteoarthritis; Mobility; Gait analysis; Kinematics; Transcriptomics; Inertial sensors; Spa Therapy
• Additional Relevant MeSH Terms: Musculoskeletal Diseases; Arthritis; Joint Diseases; Rheumatic Diseases; Osteoarthritis; Osteoarthritis, Knee
• Other Study ID Numbers: RECHMPL25_0061; 2025-A01474-45 (Other Identifier: IDRCB)

Drug and device information, study documents

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