306 patients with Kellgren-Lawrence grade II-III knee osteoarthritis were randomized to one of three groups for intra-articular injection: 20mg extended-release triamcinolone acetonide, 40mg extended-release acetonide (ER TCA), or placebo. The purpose of this study was to examine and compare the efficacy of groups based on pain reduction relative to baseline over the first 24 weeks post-injection. The primary efficacy endpoint was measured at 12 weeks post-injection. Results demonstrated significantly greater pain reduction with 20mg ER TCA compared to placebo for weeks 1-8, and significantly greater pain reduction with 40mg ER TCA compared to placebo for weeks 1-11. The primary efficacy endpoint of 12 weeks post-injection demonstrated no significant differences between either 20mg or 40 ER TCA versus placebo in pain reduction.