Intra-articular steroid injections not warranted for knee osteoarthritis, study suggests
Cartilage volume loss was significantly greater in the triamcinolone group than in the placebo group, and there was no significant difference in pain between groups.
Intra-articular steroid injections were not associated with clinical improvement in patients with knee osteoarthritis, according to a new randomized, double-blind, placebo-controlled trial.
Researchers randomly assigned 140 patients who had symptomatic knee osteoarthritis and ultrasonic features of synovitis to receive intra-articular injections of triamcinolone, 40 mg, or saline, 40 mg, every 12 weeks for two years. Enrollment began Feb. 11, 2013, and all patients had completed the study by Jan. 1, 2015. The primary outcome measures were quantitative evaluation of cartilage volume via annual knee MRI and score on the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) every three months. The study results were published in the May 16 JAMA.
Seventy patients were assigned to the triamcinolone group, and 70 patients were assigned to the saline group. Mean age among all patients was 58 years, and 54% were women. A total of 119 patients, 59 in the triamcinolone group and 60 in the saline group, completed the study, and 990 of 1,120 possible intra-articular injections were administered (88%). By the end of the study, cartilage volume loss was significantly greater in the triamcinolone group than in the saline group (mean change in index compartment cartilage thickness, −0.21 mm vs. −0.10 mm; between-group difference, −0.11 mm; 95% CI, −0.20 to −0.03 mm). No significant difference in pain between groups was noted. Treatment-related adverse events were uncommon, with five occurring in the triamcinolone group and three occurring in the saline group. The saline group also experienced a slight increase in HbA1c levels.
The researchers noted that symptoms were assessed every three months to measure long-term effects on outcomes and that pain was not assessed in the four weeks immediately following each injection. In addition, patients were asked to discontinue NSAIDs before each assessment but were allowed to continue taking any usual medications during the trial, among other limitations. However, based on their results, the researchers concluded that intra-articular steroid injections over a two-year period led to more cartilage volume loss than placebo and no improvement in knee pain. “These findings do not support this treatment for patients with symptomatic knee osteoarthritis,” the researchers wrote.