Continuous Bupivacaine Infusion versus Liposomal Bupivacaine in Adductor Canal Block for Total Knee Arthroplasty

Multimodal pain management for total knee arthroplasty (TKA) is essential to enhance functional recovery. Regional anesthesia became a vital component to decrease pain after TKA. Several studies compared femoral versus adductor canal blocks, including evaluating medications that can prolong adductor canal blocks. Liposomal bupivacaine (LB) and continuous local infusion (OnQ) both extend local anesthetic delivery beyond 24 hours. This superiority study compared the use of OnQ versus LB in adductor canal blocks. A retrospective study was conducted between two cohorts of consecutive patients who received adductor canal blocks with either LB or a continuous ropivacaine infusion catheter. Morphine equivalent dose (MED), pain scores, and length of stay (LOS) were compared between the two groups by using the analysis of covariance test. There were 106 patients in the OnQ group and 146 in the LB group. The OnQ group consumed significantly fewer opioids compared with the LB group in the recovery room (5.7 MED vs. 11.7 MED, p = 0.002) and over the entire hospitalization (the recovery room plus on the floor; 33.3 MED vs. 42.8 MED, p = 0.009). Opioid use between the OnQ and LB group did not reach statistical significance (p = 0.21). The average pain scores at rest and with activity were similar in both groups (p = 0.894, p = 0.882). The LOS between the OnQ and LB groups was not statistically significant (1.2 vs. 1.3, p = 0.462). OnQ and LB were equally effective in decreasing opioid consumption on the floor over the averaged 1.3 days of hospitalization; however, the OnQ group significantly reduced opioid use in the recovery room. There was no difference in pain scores or LOS between the two groups. OnQ comparatively prolonged infusion of local anesthetic is a potential edge over LB. This advantage may offset the inconvenience of catheter management and infrequent catheter complications.