Extended-release liposomal bupivacaine provides no benefit over standard bupivacaine for pain control after total knee replacement (TKA), according to a study presented here at the 2015 Annual Meeting of the American Academy of Orthopaedic Surgeons (AAOS).
William C. Schroer, MD, DePaul Hospital, St. Louis, Missouri, and colleagues randomised 111 patients undergoing primary TKA to receive a periarticular injection of liposomal bupivacaine or standard bupivacaine as part of an extensive multimodal pain management protocol.
Overall, 58 study patients received 20 cc (266 mg) liposomal bupivacaine mixed with 30cc (75 mg ) 0.25% bupivacaine while 53 control patients received 60 cc (150 mg) 0.25% bupivacaine. Injection technique was standardised and practiced in over 150 patients prior to initiation of the study.
Visual analogue pain (VAS) scores during hospitalisation did not differ between the liposomal bupivacaine and standard bupivacaine groups at any time point. Pain scores were 4.5 and 4.6 for the 2 groups, respectively, on day 1 (P = .73), 4.4 and 4.8 on day 2 (P = .27), and 3.5 and 3.7 on day 3 (P = .58).
Narcotic use was similar during hospitalisation. Postoperative nausea occurred in 3 (5%) patients randomised to liposomal bupivacaine and in 2 (4%) control patients.
Patients in both groups had the same degree of knee range of motion at the time of hospital discharge and at the 3-week follow-up.
Dr. Schroer cautioned that the surgeon was not blinded at the time of the injection, which may represent a potential limitation. Liposomal bupivacaine is a cloudy liquid that is more viscous and thus more difficult to inject than clear bupivacaine. For this reason, the surgeon (who was also the lead investigator) was not involved in hospital pain assessment, narcotic prescription, or knee motion measurement at 3 weeks.