Spa therapy is a potential treatment for knee osteoarthritis (KOA). The primary objective of this randomized controlled trial (RCT) was to investigate the effectiveness of a 3-week spa therapy intervention on the 6-month change in function (mobility and functional ability) of KOA patients. Secondary objectives examined the effectiveness of the intervention on KOA-related pain, stiffness, overall symptoms severity, and patient's quality of life. Community-dwelling adults, aged 50-80 years-old with KOA were randomized to spa therapy intervention or control (usual care) group. The primary outcome measure was assessed using the Western Ontario and McMaster Universities osteoarthritis index (WOMAC) function subscale. Other outcome measures were the WOMAC pain subscale and a pain visual analog scale, the WOMAC stiffness subscale, the WOMAC total scores, the EQ-5D-3 L for quality-of-life, and patient reported outcomes. Among the 173 individuals randomized, 145 (n = 74 in spa therapy, mean age 67.5 ± 6.4, 67.6% women; n = 71 in controls, mean age 68.3 ± 6.7, 64.8% women) were analyzed. A significant between-group mean difference of 11.7 points in the WOMAC function subscale, favoring the spa therapy group, was found at six months follow-up (primary outcome measure). The intervention was effective in significantly improving most secondary outcomes, including the WOMAC stiffness, pain (and pain visual analog scale) and total scores, as well as the minimum clinically meaningful changes in KOA symptoms, and patient's quality of life. Improvements were achieved during the intervention period and remained significant over the 6-month follow-up. This work demonstrated the effectiveness of spa therapy in KOA treatment.
Keywords: Balneotherapy; Function; Knee osteoarthritis; Pain; Spa therapy; Stiffness.
© 2025. The Author(s).