Objective: To compare the efficacy and adverse effects between 5 and 10 mg triamcinolone local injection for treatment of the lateral epicondylitis. The primary outcome was the improvement of pain after 12 weeks of treatment. The secondary outcome was the adverse effects rate.

Material and method: One hundred and four patients with lateral epicondylitis were randomly allocated into 2 groups. Group A were injected with 5 mg triamcinolone and group B were injected with 10 mg triamcinolone at the maximum tenderness point at the lateral aspect of the elbow. All the patients were followed-up to 12 weeks. Patient satisfaction, pain score (VAS), degree of tenderness, pain on wrist extension against resistance, grip strength and adverse effects were recorded at 12 weeks after the injection.

Results: Group A (n = 51) had excellent result 80.39%, good 11.76%, slightly improved 1.96% and not improved 5.88%. Group B (n = 53) had excellent result 73.58%, good 16.98%, slightly improved 3.77% and not improved 5.66%. The adverse effects rate were 9.8% in group A and 13.2% in group B. There were no statistically significant in terms of patient satisfaction, pain score, tenderness at lateral epicondyle, grip strength and adverse effect rate.

Conclusion: The use of 5 mg triamcinolone was comparable to 10 mg triamcinolone injected locally to treatment of lateral epicondylitis.