Introduction: Periarticular multimodal analgesic injection associates with less postoperative (post-op) pain after total knee arthroplasty (TKA) with less opioid consumption. The combination of additives and dosage are various and controversial. Evidence of ketorolac compared to triamcinolone as an additive is limited in terms of efficacy and safety. Materials and Methods: Fifty-six patients with unilateral TKA were randomized to receive either 60mg ketorolac or 80mg triamcinolone acetonide as cocktail additives in periarticular injection. Significant threshold was considered if the adjusted mean difference of morphine consumption was greater than 3mg at any timepoint. The primary outcomes were morphine consumptions at immediate post-op, 24 hour (h), 48h, and 72h post-op. Pain visual analogue scale (VAS), knee range of motion, straight leg raising ability, and adverse events were secondary outcomes. Results: Adjusted mean differences (ketorolac-triamcinolone) in morphine consumption were -0.4, 2.5, 2.6, and 2.3mg at given timepoints without significance. No difference observed in pain VAS at rest and during motion, post-op knee extension, and straight leg raising ability. However, post-op knee flexion was significantly higher in triamcinolone group at any timepoints (mean differences 10.3, 10.6, and 9.7, respectively, p<0.05). Conclusions: Periarticular analgesic injection containing 60mg ketorolac provided similar analgesic efficacy and early functional recovery compared with 80mg triamcinolone acetonide. However, triamcinolone may benefit over ketorolac in early post-op knee flexion.