The Long-term Evaluation of Glucosamine Sulphate Study

The primary aim of this study is to determine if the dietary supplements, glucosamine sulphate and/or chondroitin can limit or reduce structural disease progression whilst providing symptomatic benefit in people with osteoarthritis (OA) of the knee. The specific hypotheses to be tested in the proposed double blind, placebo-controlled, randomised clinical trial are that, compared to participants allocated to placebo, participants allocated to either or both of these dietary supplements will demonstrate: * reduced medial tibio-femoral joint space narrowing at 2 years AND; * reduced knee pain over 1 year These benefits will be achieved by participants allocated to glucosamine sulphate and/or chondroitin (the study treatments) without concomitant: * increased use of analgesics * reduced health-related quality of life * reduced participation in leisure-time physical activity