Abstract: BACKGROUND: After total knee arthroplasty, patients may experience significant pain, which has negative effects on functional recovery. Exploring and seeking effective means of analgesia has important clinical value.
OBJECTIVE: To explore an effective perioperative analgesic strategy for total knee arthroplasty patients, we first proposed a novel local infiltration anesthetic formulation consisting of morphine, flurbiprofen, and compound betamethasone, and we explored its efficacy and safety.
METHODS: This study retrospectively analyzed the clinical data of 60 patients who underwent unilateral total knee arthroplasty at First Affiliated Hospital of Anhui Medical University from November 2023 to April 2024. Based on whether local anesthesia was used during surgery, the patients were divided into the control and study groups, each consisting of 30 cases. In the study group, the local infiltration anesthesia mixture consisting of morphine, flurbiprofen, and compound betamethasone was injected into the joint cavity around the knee during surgery. No analgesic drugs were used in the control group as a blank control. We recorded and compared the postoperative visual analog scale pain scores, knee range of motion, knee function score, degree of postoperative knee edema, and incidence of postoperative complications between the two groups at different time points.
RESULTS AND CONCLUSION: (1) Compared with the control group, the visual analog scale pain score in the study group was lower at 6, 12, and 24 hours after operation, and the difference was statistically significant (Z=-2.367, -2.906, -4.199, P < 0.05). However, there was no significant difference in the pain visual analog scale score between the two groups at 48 and 72 hours after operation (Z=-1.287, -1.478, P > 0.05). (2) The postoperative knee range of motion and knee function score of the study group were better than those of the control group, and the difference was statistically significant (t=-2.519, -8.027, P < 0.05). (3) The degree of knee joint swelling in the study group was also lighter than that in the control group, and the difference was statistically significant (Z=-2.818, P < 0.05). (4) In the early postoperative period, there was no significant difference in fever between the two groups (P > 0.05). There was no poor wound healing or periprosthetic infection in the two groups. (5) The results show that applying local infiltration anesthesia composed of morphine, flurbiprofen axetil, and compound betamethasone in total knee arthroplasty can relieve early postoperative pain and show high safety. However, prospective studies with large samples are still needed to provide data support.

Key words: total knee arthroplasty, local infiltration analgesia, analgesia, compound betamethasone, visual analog scale pain score, range of motion