Sample size calculation
ROTATOR CUFF IMPINGEMENT SYNDROME
The required sample size was determined by means of power analysis on the basis of a previous study of patients with “Short term outcomes of subacromial injection of combined corticosteroid with low volume compared to high volume local anesthetic for rotator cuff impingement syndrome: a randomized controlled non inferiority trial”A power analysis program was used to calculate the number of participants required by; approximately 56 participants being required for repeated measures, with α of 0.05. A total of 64 participants was required to allow for 10% loss to follow-up. At the final analysis was analyzed power (1−β) of 80%.