The efficacy of intra-articular triamcinolone acetonide 10 mg vs. 40 mg in patients with knee osteoarthritis: a non-inferiority, randomized, controlled, double-blind, multicenter study

BACKGROUND: Intra-articular (IA) corticosteroid injection is recommended in refractory knee osteoarthritis patients. However, 40-mg of triamcinolone IA every 3 months for 2 years reduces cartilage volume as compared to saline IA. OBJECTIVE: To determine the non-inferiority of 10-mg versus 40-mg of triamcinolone acetonide (TA) for treatment of pain in symptomatic knee osteoarthritis at week 12. METHODS: This was a double-blind, randomized, controlled trial conducted in 84 symptomatic knee osteoarthritis patients. The 10-mg or 40-mg of TA were 1:1 randomized and injected to the affected knees. The primary outcome was the 12-week difference from baseline in pain VAS, with a pre-specified lower margin for non-inferiority of 10 mm. The measuring instruments used were: Visual analog scale (VAS: 0–10), modified Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), EuroQol Group 5 Dimensions (EQ5D), Knee Injuries and Osteoarthritis Outcome Score (KOOS) questionnaire, chair standing test and 20-m walking time at baseline, at week 4, and week 12 after randomization. Adverse events were recorded. RESULTS: Baseline characteristics were similar between two groups. The mean differences of pain VAS (95% confidence interval: CI) between the two groups at baseline and week 12 were 0.8 (-0.8, 2.4) with p of 0.002 for non-inferiority. There were no differences in pain reduction and quality of life improvement between 10-mg and 40-mg groups. The mean differences (95%CI) of WOMAC, KOOS pain, EQ5D and KOOS quality of life between baseline and week 12 were 0.4 (-1.1, 1.9). -8.7 (-21.3, 3.9), 1.3(-7.1, 9.6) and 1.8 (-11.5, 15.0), respectively. There were significant improvements in pain and quality of life between baseline and week 12 in both groups. CONCLUSION: The 10 mg of TA is non-inferior to 40 mg TA in improving pain in patients with symptomatic knee OA. Both 10 mg and 40 mg of TA significantly improved pain and quality of life in patients with symptomatic knee OA. TRIAL REGISTRATION: TCTR, I TCTR20210224002. Retrospectively registered 24 February 2021, http://www.thaiclinicaltrials.org/show/TCTR20210224002