The primary study endpoint was the delay between analgesic intervention and occurrence of a pain score greater than 3/10 during the first 48 postoperative hours. The equivalence margin of 90 minutes was considered clinically relevant, defining an equivalence interval between -90 and + 90 minutes. If the confidence interval of the difference in analgesia duration between the two techniques is included in this interval, the two techniques will be considered equivalent. On the contrary if the confidence interval of the difference is only partially included of not included in this interval, we will conclude to non-equivalence.