BACKGROUND: Multimodal analgesia effectively alleviates pain by additives and synergistic effect various drugs. It can avoid drug dependence and reduce adverse reactions caused by drug overdose. OBJECTIVE: To analyze the analgesic effect of morphine versus cocktail in multimodal analgesia of total knee arthroplasty (TKA). METHODS: Totally 148 patients undergoing primary unilateral TKA were enrolled. The patients were assigned by analgesic modes: group A (n=50) received the epidural injection of 3 mg of morphine before epidural tube removed; group B (n=46) was given the epidural injection of 3 mg of morphine and local injection of cocktail surrounding the knee joint before epidural tube removed; group C (n=52), received the epidural injection of same volume of normal saline and local injection of cocktail surrounding the knee joint. The patients in each group had the osteoarthritis and limited range of movement preoperatively. The postoperative Visual Analogue Scale score, muscle strength, nausea, vomiting, pruritus, and the first urination time were compared among groups. RESULTS AND CONCLUSION: (1) The postoperative Visual Analogue Scale scores at rest and in activity in the group C were significantly higher than those in the groups A and B at 6 and 12 hours (P < 0.05). The q test results showed that the scores showed no significant differences between groups B and C (P > 0.05). The scores at 24 and 36 hours did not differ significantly among groups (P > 0.05). The administration rate of dezocine showed no significant difference among groups (P > 0.05). (2) The muscle strength at postoperative 6 and 12 hours in the group C was significantly higher than that in the groups A and B (P < 0.05), and no significant difference was found between groups A and B through q test (P > 0.05). (3) The incidences of urinary retention, nausea, vomiting and pruritus in the group C were significantly less than those in the groups A and B (P < 0.05), and there was no significant difference between groups A and B (P > 0.05). (4) In summary, in multimodal analgesia of TKA, epidural anesthesia of local injection of cocktail without morphine can significantly improve the early muscle strength, and reduce the complications of urinary retention, nausea, vomiting and pruritus. [ABSTRACT FROM AUTHOR]