Sydney, Sep 15 (IANS): An extract of Curcuma longa (CL) or turmeric has been found to be more effective than placebo for reducing knee pain in patients with knee osteoarthritis, say researchers.

Osteoarthritis is the most common form of arthritis, affecting millions of people worldwide. It occurs when the protective cartilage that cushions the ends of bones wears down over time.

Although osteoarthritis can damage any joint, the disorder most commonly affects joints in the hands, knees, hips and spine.

According to the study, published in the journal Annals of Internal Medicine, turmeric, however, does not affect the structural aspects of knee osteoarthritis, such as swelling or cartilage composition assessed using MRI.

"Despite its large disease burden, no approved disease-modifying drugs currently are available to treat osteoarthritis," said study authors from the University of Tasmania in Australia.

Common treatments, such as acetaminophen and nonsteroidal anti-inflammatory drugs have only mild to moderate effects and are associated with adverse events.

As such, an urgent need exists for safer and more effective drugs to treat osteoarthritis.

For the current findings, the research team randomly assigned 70 participants with symptomatic knee osteoarthritis and ultrasound evidence of effusion (swelling inside the knee joint) to receive either two capsules per day of CL or matched placebo for 12 weeks to determine the efficacy of CL for reducing knee symptoms and joint swelling.

Changes in pain and knee effusion-synovitis volume were assessed by a standardized questionnaire and MRI, respectively, over 12 weeks.

The researchers also looked for changes in cartilage composition, pain medication usage, quality of life, physical performance measures, and adverse events.

After 12 weeks, they found that patients taking the turmeric supplements reported less pain than those in the placebo group with no adverse events.

Besides, participants in the turmeric group consumed fewer pain medications compared to the participants in the placebo group.

There was no difference in the structural aspects of knee osteoarthritis between the groups.

Due to the modest effect of the turmeric extracts on knee pain, a small sample size of the study, short-duration of follow-up and the single research centre, the researchers suggest that multicenter trials with larger sample sizes and longer duration of follow-up are needed to assess the clinical significance of their findings.