Impact of Liposomal Bupivacaine Administration on Postoperative Pain in Patients Undergoing Total Knee Replacement

STUDY OBJECTIVE To determine whether liposomal bupivacaine, a long-acting anesthetic indicated for single-dose wound infiltration to produce postoperative analgesia, has an impact on postoperative pain in patients undergoing total knee arthroplasties (TKAs). DESIGN Single-center retrospective cohort study. SETTING Large tertiary and quaternary care hospital. PATIENTS A total of 120 adults who underwent TKA between March 1, 2013, and October 31, 2013; of those patients, 55 patients received an intraoperative dose of liposomal bupivacaine 266 mg (active treatment group), and 65 did not receive the drug (control group). MEASUREMENTS AND MAIN RESULTS The primary end point was the mean area under the curve (AUC) of numeric rating scale (NRS) pain scores from the end of surgery to 48 hours after surgery. Secondary end points included measures of postoperative pain up to 24 hours after surgery, opioid consumption within 48 hours after surgery, duration of hospitalization, and ambulation distance from the end of surgery to discharge. No significant differences were noted in the primary or secondary end points between patients who received or did not receive an intraoperative dose of liposomal bupivacaine. The mean +/- SD AUC of NRS pain scores was 199.59 +/- 67.11 and 192.94 +/- 70.41 for the liposomal bupivacaine and control groups, respectively (p=0.658). Use of adjunctive analgesics was higher among patients in the control group, particularly for those receiving celecoxib, pregabalin, and continuous regional ropivacaine infusions, which may have minimized any differences in pain control between the treatment groups. CONCLUSION Liposomal bupivacaine did not improve pain control in patients undergoing TKA when compared with historical management strategies; however, differences may have been obscured by increased utilization of adjunctive analgesics among patients in the control group.