Postoperative Analgesia with Adductor Canal Block using Ropivacaine, Buprenorphine and Dexamethasone versus Ropivacaine and Dexamethasone in Knee Surgery Patients: A Randomised Controlled Trial

Introduction: The adductor canal nerve block has become contemporary, safe, highly effective and minimally invasive approach with faster sensory onset and greater success rate, without causing any quadriceps weakness, for postoperative pain management in knee surgery patients. The duration of block can be prolonged with addition of multiple perineural adjuvants, reducing the requirement of continuous catheters and other parenteral or oral analgesics. Aim: To compare postoperative analgesia provided by addition of Buprenorphine and Dexamethasone to Ropivacaine vs addition of Dexamethasone alone. Materials and Methods: A randomised controlled double-blind trial was conducted at a tertiary care rural teaching hospital in Gujarat, India. A total of 70 patients aged 18 to 75 years, planned for knee surgeries, were randomised in two groups using web-based program. Group A received 25 mL of 0.25% ropivacaine, 150 µg Buprenorphine, and 8 mg dexamethasone, whereas Group B received 25 mL of 0.25% ropivacaine with 8 mg dexamethasone in Adductor Canal Block (ACB) administered in immediate postoperative period. Visual Analogue Scale (VAS) score and Functional Activity Score (FAS) was recorded for next 24 hours. Duration of postoperative analgesia was determined based on time in hours at which rescue analgesia was required. The analysis was performed using STATA (14.2). Independent sample t-test was applied to contrast the mean rescue analgesia time in hours across groups. A p-value <0.05 was considered statistically significant. Results: Out of the 211 patients screened, 81 met the inclusion criteria. Eleven patients refused to participate, and 70 patients were finally randomised. The baseline parameters, viz., age, gender, and American Society of Anaesthesiologists (ASA) grade, was similar across groups. The mean±SD rescue analgesia time was significantly higher in Group A compared to Group B (12.91±2.13 vs 9.14±2.07, p-value<0.001). Similarly, the VAS and FAS profile was better in Group A compared to Group B. No side-effect was noted in either group. Conclusion: Addition of Buprenorphine as a perineural adjuvant significantly improved the duration of analgesia, as well as VAS and FAS profile in contrast to addition of only dexamethasone, without any notable side-effect/complication.