52 patients with grade IV knee osteoarthritis were randomly assigned to receive intra-articular injection of either hyaluronan (HA) or saline placebo. The purpose of this study was to determine if intra-articular HA, administered in two courses of 5 weekly injections, could delay the need for joint replacement surgery. Results demonstrated no significant difference in the time to joint replacement between the two groups. Clinical outcome, measured through the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), demonstrated a significantly greater reduction in score at 6 months following the first course of injections in the HA-treated group compared to the saline-treated group.