Triamcinolone acetonide is a commonly used corticosteroid for rheumatoid arthritis (RA) flares, providing extended relief. However, there is limited data from controlled trials comparing the efficacy of intra-articular corticosteroid (IACS) injections to standard care, particularly with non-steroidal anti-inflammatory drugs (NSAIDs). This non-randomized, single-center, open-label study evaluated the safety and efficacy of IACS injections in RA patients experiencing knee joint flare-ups. A total of 64 patients were screened and 44 received IACS (triamcinolone acetonide) and 15 were included in the control group. Significant improvements were observed in the IACS group in pain, swelling, and morning stiffness at week 2, which were sustained through weeks 6 and 12. The swollen joint count significantly reduced by week 12, while the tender joint count showed improvement by week 2. Pain reduction was substantial, as indicated by significant decrease in visual analog scale scores for pain, swelling, and mobility. The disease activity score-28 improved significantly across all time points. In addition, the C-reactive protein level decreased significantly at week 2 and its decreasing trend continued until weeks 6 and 12. By week 2, all patients had ceased NSAID use. The study demonstrated the effectiveness of IACS in reducing RA flare severity, particularly in terms of pain, swelling, and functional impairment, with no major safety concerns reported.