Knee Osteoarthritis and Thermal Spa Treatment

NCT07370480 | Recruiting DMC

• 2 other identifiers: C17572025-A00448-41
• Study Type: interventional
• Target: 76
• Locations: 1 country
• Sites: 2

Brief Summary

The goal of this interventional study is to evaluate the effectiveness at 6 months of the Enghien-les-Bains thermal spa treatment on functional disability and pain, assessed by the Minimal Clinically Important Improvement (MCII), in patients with knee osteoarthritis. The study is conducted in patients aged 50 to 80 years with knee osteoarthritis (Kellgren-Lawrence grade 2 to 4) and a baseline functional impairment defined by a normalized WOMAC function score ≥ 30. The main questions it aims to answer are:

• Does the Enghien-les-Bains thermal spa treatment result in a clinically meaningful improvement in pain and functional disability at 6 months in patients with knee osteoarthritis?
• Is the effectiveness of the Enghien-les-Bains thermal spa treatment superior to standard care, as assessed through an indirect comparison with an external control group from the ANGELLO randomized controlled trial (NCT0581943)? Patients receiving the Enghien-les-Bains thermal spa treatment are compared to the external control group of the ANGELLO randomized controlled trial (Saint-Jean-d'Angély), composed of non-spa-treated patients receiving standard care, to assess differences in pain and functional disability outcomes at 6 months. Patients of the study:
• Undergo a standardized thermal spa treatment at Enghien-les-Bains.
• Continue usual medical care for knee osteoarthritis.
• Complete questionnaires and clinical assessments at baseline and at 6 months.

Conditions

Knee Osteoarthritis

Keywords

spa therapy; thermal treatment; balneotherapy; Rheumatology

Outcome Measures

Primary Outcomes (2)

• Minimal Clinically Important Improvement (MCII) at 6 months

  MCII is defined as a pain reduction of 19.9 mm or more on a 0-100 visual analogic scale (VAS), where 0 means no pain and 100 worse pain. The percentage of patients achieving MCII is calculated and compared with that of the control group in the reference RCT (external comparison).

  6 months

• Minimal Clinically Important Improvement (MCII) at 6 months

  MCII is defined as a reduction of 9.1 points or more in the function subscale of the Physical function subscale of the Western Ontario and McMaster Universities Arthritis Index (WOMAC) in absence of knee surgery. WOMAC is a self-administered questionnaire that consists in 17 items: (17 items): using stairs, rising from sitting, standing, bending, walking, getting in / out of a car, shopping, putting on / taking off socks, rising from bed, lying in bed, getting in / out of bath, sitting, getting on / off toilet, heavy domestic duties, light domestic duties. The 100-normalized subscale score ranges from 0 (none) to 100 (worse functional limitations). The percentage of patients achieving MCII is calculated and compared with that of the control group in the reference RCT (external comparison).

  6 months

Secondary Outcomes (23)

• Change from baseline of pain-related knee osteoarthritis at 20 days

  Day 1 and 20 days

• Change from baseline of pain-related knee osteoarthritis at 3 months

  Day 1 and 3 months

• Change from baseline of pain-related knee osteoarthritis at 6 months

  Day 1 and 6 months

• Change from baseline of the pain subscale of the WOMAC at 20 days

  Day 1 and 20 days

• Change from baseline of the pain subscale of the WOMAC at 3 months

  Day 1 and 3 months

Other Outcomes (1)

• Qualitative assessment of participant experience and engagement with the thermal spa treatment

  Day 20

Study Arms (1)

Thermal spa treatment

EXPERIMENTAL

18-day spa program with Waters of Enghien-les-Bains in addition to standard of care for knee osteoarthritis

Other: Thermal spa sessions; Other: Thermal water; Other: Standard of Care for Knee Osteoarthritis

Interventions

Thermal spa sessions OTHER

At least 4 spa sessions per day, 6 days a week during 3 consecutive weeks that may include daily: one whirlpool bath, one poultice application, one overall jet shower and one underwater massage with thermal water. With the exception of the application of mud poultices and whirlpool bath, which cannot be substituted, other treatments may be replaced by: immersion bath with shower, penetrating shower, and local jet shower. 10-minute air diffusion baths are taken in individual tubs at 37°C. Mud is applied for 10 minutes as a poultice to both knees (minimum 2 per knee, 45°C), if necessary, to other painful osteoarthritis areas. A 3-minute overall jet shower is administered by a thermal spa staff member, using thermal water at 37°C. A 10-minute underwater massage is administered by a physiotherapist, under a thermal water spray bar at 37°C.

Thermal spa treatment

Thermal water OTHER

The water has a neutral pH (7), is cold (14 °C), and presents a moderate level of mineralization (571 mg/L) with a balanced ionic profile. It contains calcium (128 mg/L), bicarbonates (440 mg/L), sulfates (93 mg/L), magnesium (27.9 mg/L), and sodium (12.4 mg/L).

Also known as: Natural Mineral Water of Enghiens-les-Bains

Thermal spa treatment

Standard of Care for Knee Osteoarthritis OTHER

Participants continue standard medical care for knee osteoarthritis as prescribed by their primary care physician, including analgesics and physiotherapy, according to routine clinical practice.

Thermal spa treatment

Eligibility Criteria

• Age: 50 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Knee osteoarthritis with Kellgren and Lawrence stage 2 to 4 evidenced by a knee X-ray examination in the past 3 years.
• normalized score of the WOMAC physical function subscale greater than or equal to 30.
• Signed inform consent.
• With health insurance affiliation.

You may not qualify if:

• Presented with balneotherapy contraindication or to certain adjuvant treatment techniques (balneation, hydrotherapy jets, massage): chronic infectious pathology, active cancer, decompensated cardiac, hepatic or renal insufficiency, "open" leg ulcer, immune deficiency, phlebitis, erysipelas or history of erysipelas, active thrombosis, behavioral disorders, etc.
• Presented with chronic pain for reasons other than osteoarthritis: chronic inflammatory rheumatism (rheumatoid arthritis, ankylosing spondylitis, lupus, psoriatic arthritis) or fibromyalgia.
• Patient scheduled for knee osteoarthrosis-related surgery within the next 7 months.
• Having had spa treatment in the past 6 months whatever the indication or intra-articular corticosteroid injection within the previous 90 days or hyaluronic acid infiltration or other viscosupplementation or platelet-rich plasma (PRP) injection within the previous 6 months.
• Residing more than 30 kilometers from Enghien-les-Bains at the time of spa treatment.
• Women of childbearing potential who are not using effective contraception (estrogen/progestin or progestin-only oral, vaginal, transdermal, injectable or subcutaneous) or who plan to discontinue contraception within the next 7 months.
• Likely to be unable to comply with protocol or to attend visits, particularly in view of the duration of the research, or unable to read or understand French.
• Regulatory reason (guardianship or already enrolled in a clinical trial).

Sponsors & Collaborators

• CEN Biotech: lead
• Town Hall of Enghien-les-Bains: collaborator

Study Sites (2)

Thermes d'Enghien-les-Bains

Enghien-les-Bains, 95880, France

RECRUITING

Thermes d'Enghien-les-Bains

Enghien-les-Bains, Île-de-France Region, 95880, France

NOT YET RECRUITING

Related Publications (1)

• Forestier R, Debiais F, Michel N, Schueller R, Juhel C. The effectiveness of a 3-week spa therapy on the 6-month mobility and functional ability of patients with knee osteoarthritis: the ANGELLO randomized controlled trial. Int J Biometeorol. 2025 Jul;69(7):1715-1724. doi: 10.1007/s00484-025-02927-2. Epub 2025 May 13.

  PMID: 40358707 BACKGROUND

MeSH Terms

Conditions

Osteoarthritis, Knee

Interventions

Water Pollution; Standard of Care

Condition Hierarchy (Ancestors)

Osteoarthritis; Arthritis; Joint Diseases; Musculoskeletal Diseases; Rheumatic Diseases

Intervention Hierarchy (Ancestors)

Environmental Pollution; Public Health; Environment and Public Health; Quality Indicators, Health Care; Quality of Health Care; Health Services Administration; Health Care Quality, Access, and Evaluation

Study Officials

• Magali Ballard, MD

  PRINCIPAL INVESTIGATOR

Central Study Contacts

Christine Juhel, Ph.D

CONTACT

+33380680511; christine.juhel@groupecen.com

Amandine Fry

CONTACT

amandine.fry@groupecen.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: NA
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: SINGLE GROUP
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Model Details: Prospective, single-arm, superiority study with external comparison (control group of a reference RCT)

Study Record Dates

• First Submitted: January 13, 2026
• First Posted: January 27, 2026
• Study Start: January 27, 2026
• Primary Completion (Estimated): February 10, 2027
• Study Completion (Estimated): December 31, 2027
• Last Updated: January 30, 2026

Record last verified: 2026-01

Data Sharing

• IPD Sharing: Will not share

Locations

FR (2)