Comparison of postoperative analgesia by ropivacaine and bupivacaine for ultrasound-guided adductor canal block in arthroscopic knee surgery

This is a comparative interventional study to evaluate and compare the postoperative analgesia by ropivacaine and bupivacaine for ultrasound-guided adductor canal block in arthroscopic knee surgery. After obtaining Institutional Ethics Committee approval and written informed consent from patients, all patients meeting inclusion criteria will be enrolled in the study.

For adductor canal block, patient will be placed in supine position with knee slightly flexed on the side of surgery. A high frequency linear ultrasound transducer will be placed on the medial surface in midline of the thigh in the transverse plane. After visualisation of the pulsatile superficial femoral artery dorsal to the sartorial muscle, probe will be moved distally and saphenous nerve will be visualised as a hyperechoic structure anterolateral to the artery in subsartorial region. Using the in-plane technique, injection site will be confirmed with an injection of 5 ml of saline, and then 20 ml of 0.25% ropivacaine or 20 ml of 0.25% bupivacaine will be injected in Group R and Group B respectively.

After performing the block, hemodynamic parameters will be monitored and patient will be assessed for any adverse effects like local hematoma or any hemodynamic variations. In PACU, patient will be assessed at arrival and thereafter at 1, 3, 6 ,12, 18 and 24 hours for pain using Numerical Rating Scale(NRS) at rest and on movement. Injection tramadol 50 mg intravenous will be given as rescue analgesia when NRS at rest > 4. Time of requirement of first rescue analgesia and total dose of tramadol required in first 24 hours will be noted. Quadriceps muscle strength will be assessed using MMT Score(Manual Muscle Testing Score).