Compared to adductor canal block + local anesthetic alone, the combination of adductor canal block, magnesium and bupivacaine was effective for alleviating pain and opioid consumption, without elevating nausea in people who underwent total knee arthroplasty (TKA), as elucidated from a study published in "The Clinical Journal of Pain". Investigators aimed to evaluate the influence of the addition of magnesium to local anesthetic in adductor canal block on overall patient satisfaction, nausea, opioid consumption, and postoperative pain.

A total of 119 patients undergoing TKA were incorporated and randomly segregated into 2 groups.  Participants in the Mg group (n = 56) were administered adductor canal block + magnesium and bupivacaine while participants in the no-Mg group (n = 63) were given adductor canal block + bupivacaine only.

The pain scores and the total opioid consumption in the first 48 hrs post-surgery were the major endpoints ascertained. The total overall satisfaction and the occurrence of nausea in the first 48 hrs post-surgery were the secondary outcomes ascertained.  In contrast to the no-Mg group, the Mg group exhibited reduced opioid consumption and pain scores at various time points, as depicted in Table 1:

No difference was witnessed in the overall satisfaction and occurrence of nausea over the first 48 hours following surgery. Hence, using magnesium as an adjuvant to local anesthetic in adductor canal block for same-day discharge TKA was associated with improvement in postoperative pain and reduction in opioid consumption.