Effectiveness of Two Different Volumes of Bupivacaine in Adductor Canal Block for Postoperative Analgesia after Anterior Cruciate Ligament Reconstruction

Abstract

Background: Anterior cruciate ligament (ACL) injury is corrected by arthroscopic procedure and knee arthroscopy causes severe pain. Adductor canal block (ACB) with local anesthetic solution e.g., with bupivacaine produces excellent analgesia and addition of dexamethasone provides prolong pain free period. Systemic steroidal and nonsteroidal analgesic requirement is reduced significantly. Motor function improves early and reduced tendency to fall.
Objective: The study aims to see the effectiveness of different volumes of bupivacaine in adductor canal block for postoperative analgesia after anterior cruciate ligament reconstruction operation.
Methods: This prospective,quasiexperimental study was conducted in the Department of Anaesthesia, Analgesia and Intensive Care Medicine in collaboration with the Department of Orthopaedic Surgery, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh, between October 2020 and September 2021. A total of 50 patients with ACL injury were recruited in this study and were randomized into two groups (A & B); each group had 25 patients. Group A received 15ml 0.25% bupivacaine and 0.2mg/ml dexamethasone, while group B received 20ml of 0.25% bupivacaine and 0.2mg/ml dexamethasone solution. The visual analogue scale (VAS) ranging from 0 to 10 was used to assess postoperative pain at 1 hour, 2 hour, 3 hour, 6 hour, 9 hour,12 hour, 15 hour,18 hour, 21 hour and 24 hour. Patients were assessed for the duration of analgesia by returning of pain. Injection ketorolac 30mg was given intravenously as rescue analgesic when if any patient needed. Motor functions were assessed after 24 hours by Medical Research Council (MRC) criteria to see quadriceps weakness. Postoperative complications were also observed.
Results: The VAS score was significantly lower in both group A and Group B at all time intervals except at the 18th hour. After onset of block, motor power decreased in both group but after 24 hours motor power came back to normal. There was no significant difference between two groups in case of onset of sensory block (12.51±3.78 min. vs. 11.24±3.85 min.), mean time of
first analgesic requirement (16.75±2.45 hours vs. 17.35±2.70 hours) and low analgesic requirements (39.6±6.7mg vs. 36.8±5.4 mg) in the first 24 hours (P>0.05). Patients in both groups did not have high incidence post-operative complications like nausea (12% vs. 8%), vomiting (8% vs. 12%), dizziness (8% vs. 4%). In group A, 60% of patients were satisfied and 20% were very satisfied, while in group B, 56% of patients were satisfied and 28% of the patients were very satisfied with the therapy given to them. No statistically significant difference was observed (P>0.05).
Conclusion: Our data suggest that adductor canal block (ACB) with either 15ml or 20ml of 0.25% bupivacaine improved postoperative analgesia in ACL reconstruction surgery. Both 15ml and 20ml of local anaesthetics in adductor canal provided similar effectivity in pain relief. Moreover, it preserved quadriceps motor strength. Hence, ACB could be a good option in patients undergoing ACL reconstruction.