Sinew acupuncture for knee osteoarthritis: study protocol for a randomized sham-controlled trial oleh Kwok Yin Au, Haiyong Chen, Wing Chung Lam, Chiu On Chong, Andrew Lau, Varut Vardhanabhuti, Kin Cheung Mak, Fei Jiang, Wing Yi Lam, Fung Man Wu, Hiu Ngok Chan, Yan Wah Ng, Bacon Fung-Leung Ng, Eric Tat-Chi Ziea, Lixing Lao