Intermittent treatment of knee osteoarthritis with oral chondroitin sulfate: a one-year, randomized, double-blind, multicenter study versus placebo11Principal Investigators: D. Uebelhart, MD, Assistant Professor; M. Malaise, MD, Professor, R. Marcolongo, MD, Professor; E. Vignon, MD, Professor. Co-Investigators: M. Piperno, MD, Head Physician; E. Mailleux, MD, Head Physician; A. Fioravanti, MD, Head Physician; L. Matoso, MD, Physician; Statistical analysis: F. DeVathaire, PhD, Professor; Radiological analysis: E. Vignon, MD, Professor.