Knee osteoarthritis (KOA) is a growing problem in the elderly, resulting in pain, functional limitations, disability and decreased quality of life leading to lost productivity and increased health care costs [1
]. The pathophysiological basis of KOA is multifaceted and includes intra-articular inflammation and collagen degradation, impaired muscle function, reduced proprioceptive acuity and the psychological traits of chronic pain [3
]. Currently, there are neither feasible preventive intervention strategies nor effective medical remedies for the management of KOA.
Over the past 2 decades, Tai Chi, a form of mind-body therapy, has spread worldwide for health and fitness [7
]. Tai Chi combines deep diaphragmatic breathing and relaxation with many fundamental postures that flow imperceptibly and smoothly from one to the other through slow, gentle, graceful movements. Significant improvements have been reported in balance, strength, flexibility, cardiovascular and respiratory function, and reduction of pain, depression, anxiety and arthritic symptoms in a variety of patient populations including KOA [8
Thus, Tai Chi has the potential to become a novel, logistically feasible way of providing standardized exercises with a complementary mind-body approach to the management of KOA. The physical component provides exercise that is consistent with recommendations for OA (range of motion, flexibility, muscle conditioning, and aerobic cardiovascular exercise) [9
], while the mind component has the potential to increase psychological well-being, life satisfaction, and perceptions of health [10
]. These effects are especially pertinent for the treatment of older adults who have OA with knee pain and poor physical function.
To date, only five randomized controlled trials (RCTs) conducted between 2000 and 2007 have compared the effect of Tai Chi with various controls in patients with OA [11
]. The results of three RCTs suggested significant pain reduction compared to controls [11
], but the other two found no significant changes [14
]. Significant improvements in physical function were also reported in three RCTs compared with controls [11
], but no effects were seen in the other two [12
]. Of the two RCTs [14
] that evaluated the effects of Tai Chi on quality of life, only one reported positive results for Tai Chi compared with controls [15
]. In addition, only two RCTs reported significant differences between Tai Chi and control in improvements in flexibility or balance [11
]. Heterogeneity of controls, different Tai Chi styles, doses and duration in addition to multiple OA sites prohibit a meaningful comparison across these trials. Furthermore, the absence of radiographic evidence of KOA as specified by the ACR criteria for OA [14
], high dropout rates [13
], small sample size [11
], the lack of standardized outcome measures and short follow up [11
] limit widespread applicability of the results from these studies.
Because the overall findings from these RCTs suggest some favorable effects of Tai Chi on pain, physical function, quality of life, balance and flexibility in patients with KOA, a well designed study may be able to overcome the limitations of the previous studies and provide a more useful treatment. We hypothesize that Tai Chi may be beneficial to patients with KOA as a result of an effect on muscle strength, flexibility, pain, stress and anxiety as well as "mind-body" interactions. We therefore designed a 12 week trial with long term 1 year follow up to obtain data on the effects of Tai Chi on pain (as a marker of disease activity), functional independence (a marker of impairment), disability, joint proprioception and health status in elderly people with KOA.
In this paper, we present the design and detailed protocol of a single-blinded, randomized controlled trial as well as a discussion of the overall challenges of conducting this trial with respect to strategies for recruitment, avoidance of selection bias, the actual practice of Tai Chi, and the maximization of adherence/follow-up. We report ways to overcome the theoretical and logistic limitations and problems of conducting such a clinical trial. The results from this trial will be reported at the completion of the study in accordance with the Consolidation of Standards for Reporting Trials guidelines [16