Yoga or Strengthening Exercise for Knee Osteoarthritis: A Randomized Clinical Trial

Abstract

Importance: There is limited evidence on the comparative effectiveness of different exercise modalities, such as yoga and strengthening exercises, for managing knee osteoarthritis (OA).

Objective: To compare the effectiveness of yoga vs strengthening exercise for reducing knee pain over 12 weeks in patients with knee OA.

Design, setting, and participants: This single-center, assessor-blinded (for nonpatient-reported outcomes), parallel-arm, active-controlled, superiority randomized clinical trial included adults aged 40 years or older with knee OA and knee pain levels of 40 or higher on a 100-mm visual analog scale (VAS) in Southern Tasmania, Australia. Participants were recruited from April 2021 to June 2022, and follow-up was completed in December 2022. Data were analyzed from May 2023 to July 2024.

Interventions: Participants were randomized 1:1 to the yoga and strengthening exercise groups. Both groups attended 2 supervised and 1 home-based session per week for 12 weeks followed by 3 unsupervised home-based sessions per week for weeks 13 to 24.

Main outcomes and measures: The primary outcome was the between-group difference in VAS score over 12 weeks assessed using a range of 0 (no pain) to 100 (worst possible pain) with a prespecified noninferiority margin of 10 mm. Secondary outcomes included knee pain over 24 weeks; Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) knee pain, function, and stiffness; patient global assessment; Osteoarthritis Research Society International-Outcome Measures in Rheumatology Clinical Trials response; physical performance measures; leg muscle strength; health-related quality of life assessed via the Assessment of Quality of Life-8 Dimensions (AQol-8D) utility score; depression assessed with the Patient Health Questionnaire-9; and neuropathic pain assessment over 12 and 24 weeks. Analyses were based on the intention-to-treat principle.

Results: In total, 117 participants were randomized to the yoga (n = 58) or strengthening exercise (n = 59) program. Baseline characteristics of the participants were similar, with a mean (SD) age of 62.5 (8.3) years, and 85 participants (72.6%) were female. The mean (SD) baseline VAS knee pain score of 53.8 (16.0) indicated moderate knee pain. Over 12 weeks, the between-group mean difference in VAS knee pain change was -1.1 mm (95% CI, -7.8 to 5.7 mm), which was not statistically significant but remained within the prespecified noninferiority margin. Of 27 secondary outcomes assessed over 12 and 24 weeks, 7 were statistically significant in favor of yoga. The yoga group showed modestly greater improvements than the strengthening exercise group (between-group differences) over 24 weeks for WOMAC pain (-44.5 mm [95% CI, -70.7 to -18.3 mm]), WOMAC function (-139 mm [95% CI, -228.3 to -49.7 mm]), WOMAC stiffness (-17.6 mm [95% CI, -30.9 to -4.3 mm]), patient global assessment (-7.6 mm [95% CI, -15.1 to -0.2 mm]), and 40-m fast-paced walk test (1.8 [95% CI, 0.4-3.2]). In addition, the yoga group had a modestly greater improvement than the strengthening exercise for depression at 12 weeks (between-group difference in PHQ-9 score, -1.1 [95% CI, -1.9 to -0.2]) and quality of life at 24 weeks (between-group difference in AQoL-8D score, 0.04 [95% CI, 0.0 to 0.07]). Adverse events were similar in both groups and mild.

Conclusion and relevance: In this randomized clinical trial, yoga did not significantly reduce knee pain compared with strengthening exercises. However, yoga was found to be noninferior to strengthening exercises, suggesting that integrating yoga as an alternative or complementary exercise option in clinical practice may help in managing knee OA.

Trial registration: ANZCTR.org Identifier: ACTRN12621000066886.

Figure 1.. Screening, Randomization, and Completion of 12- and 24-Week Follow-Up

Figure 2.. Mean Visual Analog Scale (VAS) Knee Pain and Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index Subscale Scores in the Yoga and Strengthening Groups Over 24 Weeks

Values are adjusted means, error bars indicate 95% CIs, and P values correspond to between-group differences observed at 24 weeks. Data are estimates from linear mixed effect models with all 117 participants included in the analysis. Scores on the VAS range from 0 to 100, with higher scores indicating more severe symptoms. Scores on the WOMAC pain index ranged from 0 to 500; on the WOMAC function index, from 0 to 1700; and on the WOMAC stiffness index, from 0 to 200, all 3 with higher scores indicating more severe symptoms.