91 patients with knee osteoarthritis were randomized to receive either 5 weekly intra-articular injections of hyaluronan, or to receive 5 placebo intra-articular injections. The purpose of the study was to determine the clinical effects of hyaluronan injection therapy, in terms of its efficacy and safety. Outcomes included VAS pain scores, knee tenderness, and range of motion assessed up to 5 weeks after the start of treatment. Additionally, adverse events and global assessments for patient and investigator were recorded. Results indicated no significant benefit of hyaluronan treatment over placebo for any outcome measure. A greater proportion of hyaluronan patients experienced pain and/or swelling at the injection site compared to patients in the placebo group.