[Effect of electroacupunture on supplementary analgesia and the levels of serum β-endorphin and prostaglandin E₂ in patients with total knee arthroplasty]

Objective: To observe the effect on supplementary analgesia after total knee arthroplasty (TKA) treated with electroacupunture, and explore it's mechanism.

Methods: A total of 40 patients with severe knee osteoarthritis were randomized into an observation group and a control group, 20 cases in each one. During the operation, patients were given epidural anesthesia in the two groups, conventional patient controlled epidural analgesia and oral celecoxib were applied after the operation. In the observation group, electroacupunture was used at Liangqiu (ST 34), Xuehai (SP 10), Yinlingquan (SP 9), Zusanli (ST 36), Fenglong (ST 40) and Qiuxu (GB 40) on the operation side from the 1st to 7th day after the operation to support analgesia, 30 min for each time, once a day. The visual analogue scale (VAS) was used to record postoperative pain of resting state and active state. The levels of serum prostaglandin E₂ and β-endorphin were measured on the 1st and 7th day after surgery in the two groups.

Results: In the observation group, the VAS scores of resting state and active state were superior to the control group on the 3rd, 5th and 7th day after the operaton (all P<0.05); after the treatment, the level of serum β-endorphin was increased and the level of serum prostaglandin E₂ was reduced in the two groups (all P<0.05), and the change of the observation group was larger than that of the control group (both P<0.05).

Conclusion: Electroacupunture has the effect of supplementary analgesia for patients after TKA, the mechanism may be related to promote the synthesis of β-endorphin and inhibit the synthesis of prostaglandin E₂.