Current pharmacologic therapies for patients with osteoarthritis are suboptimal.
To determine the efficacy of 
Randomized, double-blind, placebo-controlled trial. (Australian New Zealand Clinical Trials Registry: ACTRN12618000080224).
Single-center study with patients from southern Tasmania, Australia.
70 participants with symptomatic knee osteoarthritis and ultrasonography-defined effusion-synovitis.
2 capsules of CL (
The 2 primary outcomes were changes in knee pain on a visual analogue scale (VAS) and effusion-synovitis volume on magnetic resonance imaging (MRI). The key secondary outcomes were change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and cartilage composition values. Outcomes were assessed over 12 weeks.
CL improved VAS pain compared with placebo by -9.1 mm (95% CI, -17.8 to -0.4 mm [
Modest sample size and short duration.
University of Tasmania and Natural Remedies Private Limited.
CL was more effective than placebo for knee pain but did not affect knee effusion-synovitis or cartilage composition. Multicenter trials with larger sample sizes are needed to assess the clinical significance of these findings.