Randomized controlled trial of a simplified adductor canal block performed for analgesia following total knee arthroplasty

Background and objectives The objective of the study was to determine if injection of local anesthetic into the vastus medialis and sartorius muscles adjacent to the adductor canal produces sensory changes comparable with adductor canal block (ACB). This could result in a technically easier and potentially safer alternative to ACB. Methods In this randomized controlled trial, patients received either ACB (n=20) or a simplified adductor canal (SAC) block performed using a new fenestrated nerve block needle (n=20). The time to perform each block as well as the number of attempts to position the needle were evaluated. A non-inferiority test was used to compare pain scores and opioid requirements for the ACB and the SAC block. Results The SAC block was performed more rapidly, with fewer needle passes, and had a higher success rate than the ACB. Three block failures and two vessel punctures were observed in the ACB group, while none of these events occurred in SAC block patients. Analgesia and opioid consumption for patients treated with the SAC block were not inferior to ACB. Conclusion The SAC block is technically easier to perform and potentially safer than ACB. This procedure can be performed using easily visible ultrasound landmarks and has the potential for use among a wide range of healthcare providers. Trial registration number NCT02786888 .