Adductor canal block for post-operative analgesia after simultaneous bilateral total knee replacement: A randomised controlled trial to study the effect of addition of dexmedetomidine to ropivacaine

BACKGROUND AND AIMS: Knee replacement surgery causes tremendous post-operative pain and adductor canal block (ACB) is used for post-operative analgesia. This is a randomised, controlled, three-arm parallel group study using different doses of dexmedetomidine added to ropiavcaine for ACB. METHODS: A total of 150 patients aged 18–75 years, scheduled for simultaneous bilateral total knee replacement, received ultrasound-guided ACB. They were randomised into three groups -Group A received ACB with plain ropivacaine; Groups B and C received ACB with ropivacaine and addition of dexmedetomidine 0.25 μg/kg and 0.50 μg/kg, respectively, on each side of ACB. The primary outcome was the duration of analgesia. Total opioid consumption, success of early ambulation, and level of patient satisfaction were also assessed. RESULTS: The patient characteristics and block success rates were comparable in all groups. Group C patients had longer duration of analgesia (Group C 18.4 h ± 7.4; Group B 14.6 ± 7.1; Group A 10.8 ± 7; P < 0.001); lesser tramadol consumption (Group C 43.8 mg ± 53.2; Group B 76.4 ± 49.6; Group A 93.9 mg ± 58.3; P < 0.001) and lesser pain on movement (P < 0.001). The patients in Group B and C walked more steps than in Group A (P < 0.002). The level of patient satisfaction was highest in Group C (P < 0.001). CONCLUSIONS: The addition of dexmedetomidine to ropivacaine resulted in longer duration of analgesia after adductor canal block for simultaneous bilateral total knee replacement surgery.