6Salter RB, Simmonds DF, Malcolm BW, et al. The biological effect of continuous passive motion on the healing of full-thickness defects in articular cartilage. J Bone Joint Surg, 1980,62 : 1232.
7Kuptniratsaikul V, Tosayanonda O, Nilganuwong S, et al. The efficacy of a muscle exercise program to improve functional performance of the knee in patients with osteoarthritis. J Med Assoc Thai,2002,85:33-40.