The effect of balneotherapy and peloid therapy on changes in the functional state of patients with knee joint osteoarthritis: a randomized, controlled, single-blind pilot study
Key Findings
- RCT demonstrating significant improvement in knee osteoarthritis functional state
- Peloid therapy showed superior outcomes to control group
- Supports combined thermal-chemical mechanism of peloid therapy
Randomized controlled pilot study published in the International Journal of Biometeorology, comparing balneotherapy and peloid therapy for knee osteoarthritis. With 44 citations, it is a well-referenced addition to the RCT evidence base and forms part of the cluster of controlled trials that the Keilani 2025 systematic review drew upon.
Design
Single-blind randomized controlled design, with separate groups receiving balneotherapy (immersion), peloid therapy (direct pack application), and a control condition. Single-blind means the outcome assessor was blinded — patients and therapists knew their treatment, but the person measuring outcomes did not. This is the typical blinding ceiling for physical therapy trials, where full double-blinding is practically impossible.
What It Measured
The primary outcome was functional state — a composite assessment of joint function, mobility, and patient-reported capacity. This distinguishes it from pain-focused trials like Karagülle 2007: functional improvement is a harder outcome to fake or confound with expectation effects than pain relief, which has a large placebo component.
What It Found
Both balneotherapy and peloid therapy showed significant improvements in functional state compared to the control group. The study is described as a pilot, meaning it was designed to test feasibility and signal before a larger confirmatory trial. The results are directionally consistent with the rest of the peloid OA evidence — heat plus chemical content outperforms heat alone — and the functional outcome measure adds to the picture that peloid therapy’s benefits extend beyond pain relief to real-world movement capacity.
Place in the Evidence Base
Varzaityte 2019 is cited alongside Karagülle 2007, Tefner 2013, and Evcik 2007 as part of the converging RCT evidence for peloid therapy in knee osteoarthritis. Each trial used somewhat different peloid types, protocols, and outcome measures — the consistency of positive results across this variation is what supports a robust conclusion.