Turmeric eases pain but not effusion–synovitis of knee osteoarthritis

Curcuma longa (CL), or turmeric, extract appears to be effective for knee pain but has shown no impact on knee effusion–synovitis or cartilage composition, suggests a recent study.

The investigators performed a randomized, double-blind, placebo-controlled trial in a single centre. Seventy patients from Tasmania, Australia, with symptomatic knee osteoarthritis and ultrasonography-defined effusion–synovitis were randomly assigned to receive two capsules of CL (n=36) or matched placebo (n=34) per day for 12 weeks.

Changes in knee pain on a visual analogue scale (VAS) and effusion–synovitis volume on magnetic resonance imaging were the primary outcomes. Secondary outcomes included change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and cartilage composition values. Outcomes were evaluated over 12 weeks.

Compared with placebo, CL treatment resulted in improved VAS pain by –9.1 mm (95 percent confidence interval [CI], –17.8 to –0.4; p=0.039) but did not affect effusion–synovitis volume (3.2 mL, 95 percent CI, −0.3 to 6.8). CL also improved WOMAC knee pain by –47.2 mm (95 percent CI, –81.2 to –13.2; p=0.006) but not lateral femoral cartilage T2 relaxation time (–0.4 ms, 95 percent CI, –1.1 to 0.3).

There was a similar incidence of adverse events in the CL (n=14; 39 percent) and placebo (n=18; 53 percent) groups (p=0.16). Notably, two events in the CL group and five in the placebo group appeared to be treatment-related.

The study was limited by its modest sample size and short duration, according to the investigators, adding the multicentre trials with larger sample sizes are warranted to examine the clinical significance of these findings.