Plain language summary of a pain medication (liposomal bupivacaine) for pain relief after knee replacement surgery

<b>What is this summary about?</b> This is a summary of a <b>phase 3 clinical trial</b> that compared 2 different numbing medications (called local anesthetics) with each other:
Shorter-acting bupivacaineA longer-lasting, gradual-release version of bupivacaine (called liposomal bupivacaine) Shorter-acting bupivacaine A longer-lasting, gradual-release version of bupivacaine (called liposomal bupivacaine) In both cases, the purpose of the numbing medication was to help patients not feel their knee pain after a total knee replacement operation. <b>How was the study in this summary conducted?</b> In this study, adult patients received either liposomal bupivacaine mixed with bupivacaine (liposomal bupivacaine group) or bupivacaine alone (bupivacaine group) injected using a method called an adductor canal block, which involves injecting medication into the middle of a person’s inner thigh, to relieve pain after total knee replacement. There were 85 patients in the liposomal bupivacaine group and 81 patients in the bupivacaine group who were included in the study. Pain scores, use of opioid medicines (strong medications for pain relief that have effects on the whole body and may be addictive) for pain relief, and side effects of the medications were measured after the surgery. <b>What were the results of the study?</b> Throughout the first 4 days after surgery, patients in the liposomal bupivacaine group experienced lower total pain and used less opioids (e.g., Vicodin, OxyContin, and Percocet) to manage their pain than patients in the bupivacaine group. Additionally, patients in the liposomal bupivacaine group went for a longer time before needing opioids for pain relief than patients in the bupivacaine group. The most common side effects in both groups were nausea and constipation. <b>What do the results of the study mean?</b> In this study, patients in the liposomal bupivacaine group took less opioids to manage their pain than patients in the BUPI group and still experienced less total pain. The longer-lasting liposomal bupivacaine medication appears to be a better treatment for pain control than the shorter-acting bupivacaine medication after a total knee replacement. <b>Clinical trial number</b>: NCT05139030