Twelve trials (682 participants) were included in the review: five randomised controlled trials (RCTs, 322 participants) and seven non-randomised controlled trials (CCTs, 360 participants). Two RCTs scored 4 points on the Jadad scale, while three RCTs scored 3 points. Five CCTs scored 1 point on the Jadad scale and two CCTs scored 0 points. All five RCTs described the method of randomisation. Three RCTs reported details of allocation concealment. Ten trials reported sufficient details of withdrawals and dropouts. Significant heterogeneity was reported between studies (data not reported).
Pain (five RCTs, six CCTs): Statistically significant greater reductions were reported for pain scores for Tai Chi compared with: attention control program for VAS pain scores (p<0.05, one RCT) and routine treatment for WOMAC pain scores (p<0.05, one RCT) for osteoarthritis of the knee; no treatment (p values ranging from <0.05 to <0.0001, three CCTs); an arthritis self-help management programme for the WOMAC scale (p<0.05, one CCT); either aquatic exercise (p<0.05) or a self help management program (p<0.05, one CCT).
However no statistically significant reductions on pain subscales were reported for AIMS or WOMAC pain scores comparing Tai Chi with physical activity, hypnotherapy or waiting list, or bingo recreation for multiple sites of pain (three RCTs), or comparing Tai Chi with an arthritis self-help management program using the VAS scale (one CCT).
Function (four RCTs, two CCTs): Significant improvements in physical function were found for Tai Chi compared with: routine treatment for ADL scale pain scores (p<0.01, one RCT); waiting list control for WOMAC scales pain scores (p<0.05, one RCT) but not for Tai Chi compared to hydrotherapy. Significant improvements were also found for Tai Chi compared with a self-help management programme (p<0.05, one CCT); or no treatment for ADL scores pain scores (p<0.05, one CCT). But no significant differences for function were found comparing Tai Chi with attention control (one RCT) or bingo recreation (one RCT).
Balance (one RCT, five CCTs): Tai Chi was reported to significantly improve balance in comparison with: routine treatment (p<0.005, one RCT); or no treatment for two CCTs (p<0.01 and p<0.05) but not for one CCT. Two CCTs reported significant improvement with Tai Chi compared to self help management programmes (p<0.05 and p<0.01).
Flexibility (four CCTs): Significant improvements were reported in flexibility for Tai Chi groups compared to no treatment for one CCT (p<0.05) but two CCTs show no significant differences. One CCT reported significant improvements in angle of right ankle dorsiflexion (p<0.01) for Tai Chi compared with self-help management programmes.
Quality of life (two RCTs, one CCT): Improved results for AIMS subscales for tension (p<0.005) and satisfaction (p<0.001) were reported for Tai Chi compared with routine care (one RCT), but no statistically significant differences were found for comparisons with hydrotherapy or waiting list (one RCT) or no treatment (one CCT).