The effects of Tai Chi on clinical outcomes and gait biomechanics in knee osteoarthritis patients: a pilot randomized controlled trial

Knee osteoarthritis (KOA) is a common degenerative joint disease that significantly reduces mobility and quality of life in elderly populations. Tai Chi, a low-impact mind-body exercise, has been suggested as a potential non-pharmacological intervention for managing KOA, but its biomechanical effects remain unclear. This study aimed to evaluate the effects of a 14-week Tai Chi program on clinical symptoms, lower limb biomechanics, and muscle activation patterns in elderly patients with KOA. A single-blinded randomized controlled trial was conducted, enrolling 24 participants aged 55-70 years with unilateral KOA. Participants were randomly assigned to a Tai Chi intervention group or a control group receiving health education only. Primary outcomes included joint range of motion, joint moments, and muscle activation, measured using a motion capture system and surface electromyography. Secondary outcomes, such as pain, stiffness, function (WOMAC), balance (BBS), and quality of life (SF-12), were also assessed pre- and post-intervention. The Tai Chi group demonstrated significant improvements in WOMAC pain (-1.58 ± 1.44 vs. 0.11 ± 0.78, p = 0.01), stiffness (-0.33 ± 0.78 vs. 0.56 ± 0.88, p = 0.02), and function scores (-2.58 ± 3.53 vs. 1.00 ± 2.78, p = 0.02) compared to the control group. Balance (BBS: 1.42 ± 1.88 vs. -0.89 ± 1.27, p = 0.01) and physical health (SF-12 PCS: 5.45 ± 6.76 vs. -1.05 ± 2.17, p = 0.01) were also enhanced. Biomechanically, Tai Chi reduced horizontal plane knee ROM (-3.03 ± 1.00°, p = 0.01) and maximum knee extension moments (affected side: -0.09 ± 0.04 N/kg, p = 0.04, Non-affected side: -0.11 ± 0.05 N/kg, p = 0.03). Tibialis anterior muscle activation increased significantly (5.66 ± 1.05%MVIC, p = 0.02), while other muscles showed non-significant trends. Tai Chi demonstrated significant clinical and biomechanical benefits for elderly KOA patients, suggesting its potential as a safe, accessible, and effective therapeutic intervention.