Discussion
osteoarthritis, volume loss, knee osteoarthritis, pain
OSTEOARTHRITIS, SECONDARY, KNEE OSTEOARTHRITIS
This study was the first randomized controlled trial which compared the efficacy of IA 10 mg and 40 mg TA injection for the treatment of symptomatic knee osteoarthritis. This trial reported the non-inferiority of the 10 mg TA compared with the 40 mg TA to reduce pain in patients with knee osteoarthritis. Both 10 mg and 40 mg TA were effective to relieve pain, improve function, quality of life and global assessment in patients with symptomatic knee osteoarthritis.Patients in this study represent severe symptomatic knee osteoarthritis patients in a real-life practice who are indicated to receive IA glucocorticoid. The majority of patients are elderly, female and overweight. However, patients in this study are Asian which have lower body mass index compared to previous trials conducted in the Western countries [There was no published recommendation on the intraarticular dosages and type of glucocorticoid to treat symptomatic knee OA. Various types and dosages of IA glucocorticoids were previously investigated to treat symptomatic knee OA such as TA, triamcinolone hexatonide, methylprednisolone, prednisolone acetate, dexamethasone phosphate, and hydrocortisone. The most investigated IA glucocorticoid for the treatment of symptomatic knee OA is triamcinolone. It is still unclear whether the efficacy of intraarticular glucocorticoid for the treatment of symptomatic knee OA is dose dependent. The dose of 40 mg was examined in many previous studies and shown to be more effective to reduce pain as compared to normal saline intraarticular [From the real-world data, a survey among members of the ACR reported that the most used glucocorticoids for intraarticular, bursa and tendon sheath injection for diverse indications including osteoarthritis are triamcinolone and methylprednisolone, and the dose of 40 mg is the most used [The data from the Cochrane meta-analyses reported the benefit of IA glucocorticoid for symptomatic knee OA peaks at 2–4 weeks and wanes overtime with the moderate benefits after 1 to 2 weeks, small to moderate after 4 to 6 weeks, small after 13 weeks, and no evidence of any benefits at 26 weeks [This study assessed various outcomes in symptomatic knee OA including pain, quality of life, and function. A 10 mg IA TA was not inferior to a 40 mg in improving pVAS in patients with symptomatic knee OA. There were no differences in other secondary outcomes. However, patients in a 40 mg TA group, not in a 10 mg group, walked faster at week 12 compared to baseline. However, there was no difference between the two groups.There are a few limitations in this study. First, due to COVID-19 pandemic, some patients could not come to the hospital at a follow-up visit. However, the coordinator informed all patients and their family about how to perform a chair stand test and record a time to 20-m walk. The questionnaires were sent and returned electronically. Secondly, the long-term cartilage volume loss with 10 mg TA intraarticular was not examined, therefore, we cannot conclude that a 10 mg TA has less damage to the cartilage compared to a 40 mg TA. A further study with cartilage volume as a primary endpoint is warranted. Thirdly, this study had no placebo, thus, it could be inconclusive whether the efficacy of TA is from the TA itself or placebo effect. Fourthly, this study was conducted in only two centers in the same country.