Magnesium sulfate enhances the effect of the peripheral analgesic cocktail in total knee arthroplasty: a systematic review and meta-analysis of randomized controlled trials

Purpose Although magnesium sulfate (MgSO 4 ) is widely used as an analgesic adjuvant to peripheral analgesic cocktails, its efficacy in total knee arthroplasty (TKA) is still controversial. Therefore, we systematically reviewed and meta-analyzed the literature to assess the analgesic efficacy of MgSO 4 as an adjuvant to the analgesic cocktail in TKA. Methods The PubMed, EMBASE, Web of Science, and Cochrane Library databases were searched. The meta-analysis was performed according to the PRISMA guidelines. Data were qualitatively synthesized or meta-analyzed using a random-effects model. Results Five randomized controlled trials involving 432 patients were included. Meta-analyses detected significant differences between the MgSO 4 and control groups in the visual analog scale (VAS) pain scores (rest) at 6, 12, and 24 h postoperatively; VAS pain scores (motion) at 12, 24, and 48 h postoperatively; morphine consumption within 24 h, 24–48 h, and during the total hospitalization period; time to first rescue analgesia after TKA; and length of hospital stay. Regarding the functional recovery, the meta-analysis demonstrated significant differences between groups in terms of knee range of motion on postoperative day 1; daily mobilization distance on postoperative day 1; and daily mobilization distance. There was no significant intergroup difference in surgical complications. Conclusion The findings suggest that MgSO 4 is a promising adjunct to the analgesic cocktail, achieving significant improvements in pain scores and total opioid consumption during the early postoperative period after TKA.