Comparing adductor canal block with local infiltration analgesia in total knee arthroplasty: A prospective, blinded and randomized clinical trial.

Study objective: Total knee arthroplasty (TKA) is associated with significant pain post-operatively. Our hypothesis is that adductor canal block (ACB) would be superior to local infiltration analgesia (LIA) in terms of providing analgesia, while still preserving quadriceps strength and enabling early postoperative rehabilitation.

Design: A prospective, blinded and randomized clinical trial between LIA and ACB was conducted. Setting: Tertiary care urban hospital. Patients: 40 patients (ASA I to III) undergoing primary TKA under single-dose spinal anesthesia were prospectively randomized from January 2014 to October 2015. Interventions: The LIA group received local infiltration of Ropivacaine 150 mg, Ketorolac 30 mg, Morphine 10 mg, and Adrenaline 200 mcg in a total volume of 75 mls, administered intraoperatively by the surgeon. The ACB group was given an ACB postoperatively by one of the study investigators at the end of surgery with 30 mls of 0.5% Ropivacaine. Measurements: The primary outcome was total Morphine consumption in the first 24 h. Secondary outcomes included total Morphine consumption in the first 48 h, pain scores, quadriceps strength, the Timed Up and Go test (TUG), the 30 s Chair Stand Test (30s-CST) and length of hospital stay. Main

Results: The median (interquartile range) 24 h Morphine consumption was 6 mg (2.3-18.3) in the ACB group and 17.5 mg (12-24.3) in the LIA group, p = 0.004. The 48 h Morphine consumption was 14.5 mg (7.5-28.5) in the ACB group as compared to 24 mg (14-33.8) in the LIA group, p = 0.03. There were no statistically significant differences in the other secondary outcomes.

Conclusion: ACB group had statistically significant reduced total Morphine consumption in the first 24 and 48 hours as compared to LIA group, with no statistically significant differences in functional outcomes of TKA patients.