Practicing the Chinese mind-body exercise (known as Tai Chi) leads to improvements in pain, function and even mental health for people with osteoarthritis of the knee.

Osteoarthritis of the knee is painful and disabling, and is becoming increasingly common as the population ages. While strengthening exercises are recommended for people with the condition, these have modest benefits for pain and physical function and may not affect psychological outcomes.

Tai Chi has been shown to improve strength and balance, reduce pain, and ease depression and anxiety in people with chronic illness, the researchers add, but evidence on its benefits for people with knee osteoarthritis has been inconclusive.

To investigate further, researchers randomly assigned 40 people in America with knee osteoarthritis to an hour of Tai Chi or an hour of wellness education and stretching exercises twice a week for 12 weeks. The average age of the participants was 65 years, and three-quarters were women. Most were overweight. No patients dropped out of the study and those in the Tai Chi group attended 85 percent of the sessions, while the control participants went to 89 percent of the sessions.

At 12 weeks, pain scores were found to be improved by 75 percent, on average, for the Tai Chi group, while function had improved by 72 percent - 57 percent and 46 percent greater than for the control-group patients, respectively. The Tai Chi group also showed significant improvements in quality of life, self-efficacy, and depression and anxiety compared to the control group, and the improvements in self-efficacy and depression persisted at week 24 and week 48. Self-efficacy refers to a person's belief that he or she can accomplish a goal.

The findings are promising because there are few efficacious long-lasting treatments for knee osteoarthritis. The researchers emphasise a need to further evaluate the biologic mechanisms and approaches of Tai Chi to extend its benefits to a broader population.