Abstract: BACKGROUND: With the continuous improvement of artificial biological materials and surgical techniques, total knee arthroplasty has become the preferred way to improve the quality of life of patients with knee osteoarthritis. However, patients with knee osteoarthritis have severe pain after knee arthroplasty, and there is no good treatment at present. Electroacupuncture therapy is a low-cost option for pain relief and has wide application prospects in combination with preemptive analgesia. 
OBJECTIVE: To investigate the effect of opposing needling acupuncture with preemptive analgesia on postoperative analgesia after initial unilateral total knee arthroplasty in patients with knee osteoarthritis. 
METHODS: Using a randomized controlled design, 120 participants were selected from Shanghai Guanghua Hospital of Integrative Medicine. All of them received the initial unilateral total knee arthroplasty. The patients were divided into three groups by using the statistical software SPSS 25: pre-electroacupuncture group, post-electroacupuncture group, and sham group, with 40 patients in each group. In pre-electroacupuncture group, opposing needling acupuncture was performed 1 day before operation, 30 minutes before anesthesia induction, and 1-3 days after operation. In post-electroacupuncture group, opposing needling acupuncture was performed with the same acupoints and parameters 1-3 days after operation, thus the sham electroacupuncture was performed 1 day before operation and 30 minutes before anesthesia induction. The sham group was treated with the same acupuncture point parameters with five times of sham electroacupuncture. The improvement of numerical rating scale after operation, the consumption of remifentanil and propofol used during operation, the time when patient first used the patient-controlled analgesia, the number of postoperative nausea and vomiting, the increase rate of thigh circumference, and the success rate of blind method were compared among the three groups. 
RESULTS AND CONCLUSION: (1) Compared with the pre-electroacupuncture group, the improvement of numerical rating scale at rest between post-electroacupuncture group and sham group on day 4 after operation was significantly reduced; the improvement of numerical rating scale at rest in sham group on day 7 after operation was significantly reduced (P < 0.05). (2) Compared with the pre-electroacupuncture group, the improvement of numerical rating scale score between post-electroacupuncture group and sham group on day 4 after operation was significantly reduced (P < 0.05), and the improvement of numerical rating scale with movement on day 7 after operation was not significant among the three groups (P > 0.05). (3) Compared with the pre-electroacupuncture group, the remifentanil consumption was significantly increased in post-electroacupuncture group and sham group (P < 0.05). (4) Compared with the pre-electroacupuncture group, the first time used the patient-controlled analgesia pump was significantly shortened in post-electroacupuncture group and sham group (P < 0.05). (5) Compared with the pre-electroacupuncture group, the number of postoperative nausea was increased in post-electroacupuncture group and sham group (P < 0.05). (6) Compared with the pre-electroacupuncture group, the increase rate of thigh circumference in post-electroacupuncture group and sham group was significantly increased on day 3 and day 7 after operation (P < 0.05). Compared with the post-electroacupuncture group, the increase rate of thigh circumference in sham group was significantly increased on day 3 and day 7 after operation (P < 0.05). (7) There was no significant difference in the success rate of blind method among the three groups (P > 0.05). (8) The artificial knee prosthesis has good biocompatibility. To conclude, opposing needling acupuncture with preemptive analgesia can relieve acute pain after total knee arthroplasty, reduce the consumption of intraoperative anesthesia, prolong the time of postoperative analgesia, alleviate postoperative adverse reactions, and reduce the increase rate of thigh circumference. 

Key words: preemptive analgesia, opposing needling acupuncture, total knee arthroplasty, osteoarthritis, postoperative acute pain