Although pain did not significantly improve in the yoga group, participants only completed about two-thirds of the recommended sessions, suggesting that more benefit may be possible with greater adherence, wrote lead author Kim L. Bennell, PhD, of the University of Melbourne, and colleagues in the Annals of Internal Medicine.
“To date, an online yoga program specifically for people with knee osteoarthritis has not been investigated,” the investigators said. “The need for such evidence-based packaged online exercise programs is highlighted in the 2020 U.S. National Public Health Agenda for Osteoarthritis.”
Methods and results
The trial involved 212 adults aged 45 years or older with symptomatic knee osteoarthritis. All patients had access to online educational materials about managing osteoarthritis.
Half of the participants were randomized into the 12-week online yoga program. This self-directed, unsupervised course consisted of 12 prerecorded 30-minute instructional yoga sessions, each with a unique sequence of poses to be completed three times in one week before moving on to the next class the following week. After 12 weeks, these participants could choose to continue doing yoga via the online program for 12 additional weeks, if desired.
The primary outcomes were knee pain and physical function, gauged by a 10-point numerical rating scale and the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), respectively. Adherence was defined as completion of at least 2 yoga sessions within the preceding week.
At the 12-week mark, the yoga group did not show any significant improvement in knee pain (–0.6; 95% confidence interval, –1.2 to 0.1), but they did achieve a mean 4-point reduction in WOMAC, suggesting significant improvement in knee function (–4.0; 95% CI, –6.8 to –1.3). Of note, however, this improvement was not enough to meet the threshold for minimal clinically important difference. At 24 weeks, the yoga group no longer showed significant improvement in knee function versus baseline.
“I don’t think a longer program would necessarily reduce knee pain, as benefits from a whole range of different types of exercise for knee osteoarthritis generally can show benefits within 8 weeks,” Dr. Bennell said in an interview.
Still, she noted that the average outcome in the trial may not represent what is possible if a patient commits to a regular yoga routine.
“I think it relates more to adherence [than duration], and I think benefits for knee pain would have been seen if a greater number of people had fully adhered to the program three times a week,” she said.
At 12 weeks, 68.8% of those in the yoga group were adherent, while just 28.4% were still adherent at week 24 after the optional extension period.
“As this was a self-directed program, adherence might be expected to be less than that of a supervised program,” Dr. Bennell noted.
Referring to unpublished data, Dr. Bennell said a sensitivity analysis showed that participants in the yoga group who completed yoga at least twice a week did show greater improvements in function and pain than those who did yoga less than twice per week.
“So it does suggest that adherence is important, as we might expect,” she said.