Evaluation of liposomal bupivacaine versus immediate release bupivacaine in post-operative pain after knee surgery

Georgia

Purpose: The use of liposomal bupivacaine, which is formulated to have an extended release, has been associated with a decrease in opiate use after total hip and knee arthroplasty. The aim of this retrospective study is to compare the use of liposomal bupivacaine and immediate release bupivacaine in patients who have undergone knee replacement. The purpose of this study is to determine the effectiveness of using liposomal bupivacaine for patients undergoing total knee arthroplasty in comparison to current practice. Methods This is a single-center, retrospective, cohort study that is being conducted in a 353 bed academic medical center. The electronic medical record system will identify patients over the age of 18 who have undergone total knee replacement and received peri-operative liposomal bupivacaine or bupivacaine. The sample size will be approximately 150 patients, who were randomly selected to maintain a 1:2 bupivacaine to liposomal bupivacaine ratio. Data on gender, pain medication use prior to admission, type of surgery performed, pain scores, pain medications (opioid and non-opioid) administered during and after surgery, time to ambulation, and length of stay will be collected and analyzed. The primary outcome is to determine if there is a reduction in the need for post-operative opioid analgesia in patients receiving liposomal bupivacaine. Secondary outcomes evaluated include length of stay, median pain scores, and cost of drug therapy in patients receiving liposomal bupivacaine compared to non-depot bupivacaine. Results Baseline demographics, including male to female ratio and age, were similar between the control group and the liposomal bupivacaine group. Though the use of opiates, calculated as morphine equivalents, in the post-anesthesia care unit (PACU) were not statistically different from one another (7.00 vs 4.89, p = 0.085), liposomal bupivacaine was associated with less opiate use post-PACU and on a daily basis (51.33 vs 28.73, p = 0.0003; 21.11 vs 12.65, p = 0.0016; respectively). Patients who received liposomal bupivacaine also ambulated faster (0.38 days vs 1.76 days, p < 0.0001) and had a shorter length of stay (1.9 days vs 2.98 days, p < 0.0001). Conclusion Pain control after total knee arthroplasty has traditionally consisted of opiate pain relievers. Our data support the data from several clinical trials, suggesting that liposomal bupivacaine is an alternative to traditional pain control, and may lead to better patient outcomes and satisfaction.