Inulin supplementation and physiotherapy for knee osteoarthritis pain: a 2×2 factorial RCT
Inulin (20 g/day) and digital physiotherapy independently reduced knee osteoarthritis pain over 6 weeks, with no synergistic effect.
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What the study showed
Inulin reduced pain (NRS Δ = −1.11; 95%CI −2.18 to −0.04; p = 0.045) and improved pressure pain thresholds, temporal summation, and grip strength versus placebo. Digital physiotherapy reduced pain (Δ = −1.55; p = 0.002) and improved TUG and 30-second sit-to-stand. No synergistic interaction between interventions was detected.
How it was done
A 2×2 factorial RCT enrolled 117 community-dwelling adults with knee OA for 6 weeks; arms were inulin 20 g/day, digital physiotherapy (Joint Academy™), combination, or maltodextrin 10 g/day as placebo. Primary outcome was NRS pain; secondary outcomes included functional tests and serum SCFAs and GLP-1.
Risk of bias
The trial was not powered to detect synergistic interaction, limiting conclusions about combined use. Six-week duration precludes long-term inference; SCFA and GLP-1 results are incompletely reported in the abstract.
What this study does NOT prove
This study does not prove that gut microbiome modulation is the mechanism underlying inulin's effect on pain.
In clinical practice
The pain reduction attributed to inulin (approximately 1 NRS point) is statistically significant but of borderline clinical relevance. Independent replication is needed before clinical adoption.
Limitations
The trial was not powered to detect synergistic interaction, limiting conclusions about combined use. Six-week duration precludes long-term inference; SCFA and GLP-1 results are incompletely reported in the abstract.
Technical appendix
Version history
- 1.0 · 2026-07-06 — Auto-generated under Evidence Standard v1.0
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