90 patients were randomized to evaluate whether subacromial injection with high-dose corticosteroid in patients with periarticular shoulder disorders was better than low-dose corticosteroid or placebo in improving pain and function. Patients received ultrasound-guided subacromial injection with triamcinolone acetonide (40 or 20 mg) or placebo and were assessed after 8 weeks. Results revealed that there were no significant differences in pain and function between high- and low- doses of corticosteroids, but both doses were more effective than the placebo.