Table 1: Effects of Tai Chi on management of osteoarthritis reported in randomized controlled trials.

First author (year) [ref.]SubjectsExercise interventionControl interventionResults

Brismée (2007) [24]Older persons (≥50 yr) with OA at knee in US, 𝑁 = 4 1 with 18% attrition in TC and 32% attrition in attention control.24-form Yang style TC (40 min/session × 3 sessions/week × 6 weeks followed by home-based TC practice at 3 sessions/week × 6 weeks), 𝑁 = 2 2 (70.8 ± 9.8 yr).Attention control program (40 min health lecture × 3 lectures/week × 6 weeks followed by no activity for 6 weeks), 𝑁 = 1 9 (68.8 ± 8.9 yr).Compared to the attention control group, TC group
(i) reduced pain (VAS, WOMAC),
(ii) improved physical function (WOMAC),
(iii) showed no difference in stiffness (WOMAC),
(iv) showed no difference in knee range of motion for flexion and extension assessed by goniometry.

Song (2003) [35]Older women (≥55 yr) with OA at multiple sites in South Korea, 𝑁 = 7 2 with 43% attrition in TC, 39% attrition in control.12-form Sun style TC modified for arthritis (60 min/session × 3 sessions/week × 2 weeks, then 60 min/session × 1 session/week × 10 weeks), 𝑁 = 2 2 (64.8 ± 6.0 yr).Telephone-contact control (usual care), 𝑁 = 2 1 (62.5 ± 5.6 yr).Compared to the control group, TC group
(i) reduced pain (K-WOMAC),
(ii) showed no difference in knee muscle strength and endurance,
(iii) improved trunk flexion and abdominal muscle strength (increased frequency of situps),
(iv) perceived fewer difficulties in physical functioning of daily living (ADL),
(v) decreased joint stiffness (K-WOMAC),
(vi) showed no difference in upper-body flexibility,
(vii) improved balance by standing longer on one foot.

Fransen (2007) [36]Older persons (ages 59–85 years) with OA at hip or knee in Australia, 𝑁 = 1 5 2 with 7% attrition in TC, 5% attrition in hydrotherapy, no dropout in control.24-form Sun style TC modified for arthritis (60 min/session × 2 sessions/week × 12 weeks), 𝑁 = 5 6 (70.8 ± 6.3 yr).Waiting list control, 𝑁 = 4 1 (69.6 ± 6.1 yr).Compared to the waiting list control group, TC group
(i) showed no difference in pain reduction (WOMAC),
(ii) improved physical function (WOMAC),
(iii) showed no difference in quality of life (SF-12),
(iv) showed no difference in depression, anxiety, and stress (DASS 21).

Hartman (2000) [37]Older person with OA at multiple sites (hip, knee, ankles, foot) in US, 𝑁 = 3 5 with 6% attrition in TC.9-form Yang style TC (60 min/session × 2 sessions/week × 12 weeks), 𝑁 = 1 7 (68.6 ± 7.9 yr).Attention control program (usual physical activity, routine care, total 3 times group meeting, and telephone discussion every 2 weeks), 𝑁 = 1 6 (67.5 ± 6.1 yr).Compared to the control group, TC group
(i) showed no difference in pain reduction (arthritis pain self-efficacy),
(ii) reduced level of tension (AIMS II),
(iii) improved self-efficacy for arthritis symptom (Arthritis Self-Efficacy Scale) and total arthritis self-efficacy,
(iv) improved satisfaction with general health including improved walking speed, bending ability, arm function, self-care activities, and household tasks (AIMS II).

Wang (2009) [38]Older persons (≥55 yr) with OA at knee in US, 𝑁 = 4 0 with no dropout.10-form Yang style TC (60 min/session × 2 sessions/week plus 20 min/day home-based TC for 12 weeks, followed by home-based TC practice for 48 weeks), 𝑁 = 2 0 (63 ± 8.1 yr).Attention control program (60 min/session of health lecture plus stretching exercise × 2 sessions/week × 12 weeks), 𝑁 = 2 0 (68 ± 7.0 yr).Compared to the attention control group, TC group
(i) reduced pain (WOMAC, VAS),
(ii) improved physical function (WOMAC, chair stand time),
(iii) showed no difference in performance for 6-minue walking test,
(iv) reduced stiffness (WOMAC),
(v) showed no difference in balance score,
(vi) improved self-efficacy,
(vii) improved health-related quality of life (SF-36),
(viii) improved depression scale (Center for Epidemiologic Studies depression scale).

Song (2007) [39]Older women (≥55 yr) with OA at multiple sites in South Korea, 𝑁 = 7 2 with 43% attrition in TC, 39% attrition in control.12-form Sun style modified TC for arthritis (60 min/session × 3 sessions/week × 2 weeks, then 60 min/session × 1 session/week × 10 weeks), 𝑁 = 2 2 (64.8 ± 6.0 yr).Telephone-contact control (usual care), 𝑁 = 2 1 (62.5 ± 5.6 yr).Compared to the control group, TC group
(i) reduced pain (K-WOMAC),
(ii) decreased joint stiffness (K-WOMAC),
(iii) showed no difference in perceived self-efficacy including perceived benefits/barriers and emotional salience (motivation scale for health Behaviors),
(iv) perceived more health benefits,
(v) performed better health behaviors, especially for diet behavior and stress management (health behavior scale).

H. Y. Lee (2008) [40]Older person with OA at knee in Korea, 𝑁 = 4 6 (75.4 ± 6.2 yr).24-form Sun style TC (60 min/session × 2 sessions/week × 12 weeks), 𝑁 = 2 2 .No treatment, 𝑁 = 2 4 .Compared to the control group, TC group
(i) reduced pain (WOAMC),
(ii) reduced stiffness (WOAMC),
(iii) improved joint motion of knee and knee rising time,
(iv) improved balance (single leg test),
(v) decreased fears of falling,
(vi) showed no difference in disability and falls efficacy.

Song (2010) [41]Older women (≥55 yr) with OA at multiple sites in South Korea, 𝑁 = 8 2 with 24% attrition in TC, 15% attrition in control.31-form Wu style TC modified for arthritis (60 min/session × 2 sessions/week × 3 weeks, then 60 min/session × 1 session/week × 6 months), 𝑁 = 3 0 (63.0 ± 7.2 yr).Self-help education program (2 hours/session × 1 session/month × 6 months), 𝑁 = 3 5 (61.2 ± 7.9 yr).Compared to the control group, TC group
(i) improved knee extensor endurance,
(ii) showed no difference in knee extensor and flexor strength,
(iii) reduced fear of falling during daily activities.

ADL: activities of daily living; AIMS: Arthritis Impact Measurement Scale; TC: Tai Chi; WOMAC: Western Ontario and McMaster Universities Osteoarthritis Index; VAS: visual analogue scale.