Liposomal Bupivacaine via an Adductor Canal Block Compared to a Peripheral Nerve Catheter and No Block After Total Knee Arthroplasty: A Retrospective Analysis.

Background As total knee arthroplasty is one of the most common surgeries in the United States, it is important to identify regional anesthesia methods that optimize patient recovery. This study evaluates the effectiveness of adductor canal (AC) blocks with liposomal bupivacaine (LB) compared to other regional anesthesia techniques. We hypothesized that patients receiving single-shot (SS) AC blocks with LB would have lower postoperative opioid consumption compared to other groups. Methods A retrospective cohort analysis was conducted on patients from a single institution between January 2014 and December 2021. The primary outcome assessed was postoperative opioid use, with secondary outcomes including postoperative pain scores and hospital length of stay. Results The final analysis included 280 patients: 41 received an SS AC block with plain local anesthetic, 76 received a peripheral nerve catheter (PNC) with continuous ropivacaine, 79 received an SS AC block with LB, and 84 received no block. In fully adjusted models, postoperative opioid consumption on day one was significantly lower in the SS AC block with LB group compared to the no block group (b = 23.2, SE = 5.7, p < 0.0001), the PNC group (b = 15.5, SE = 5.7, p = 0.01), and the SS AC block with plain local anesthetic group (b = 18.9, SE = 6.9, p = 0.01). Additionally, hospital length of stay was significantly reduced in the LB group compared to the no block group (b = 1.5, SE = 0.3, p < 0.0001), the PNC group (b = 1.1, SE = 0.3, p < 0.0001), and the SS AC block with plain local anesthetic group (b = 1.5, SE = 0.3, p < 0.0001). Conclusions Patients who received an AC block with LB had higher pain scores on postoperative day 0 (POD0) but required less opioid medication on postoperative day 1 (POD1) and had a shorter hospital stay compared to patients who received other types of AC blocks or no block.