Efficacy of Adductor Canal Blocks in Total Knee Arthroplasty

Total knee arthroplasty (TKA) is associated with significant postoperative pain. The population receiving TKA is generally elderly and often have multiple comorbidities that can present a challenge to postoperative management. Safe and effective multimodal pain management has led to improved outcomes while minimizing complications and side effects. The objective of this study was to investigate the efficacy of adductor canal blocks (ACB) in patients receiving TKA within a regional Queensland population. We performed a retrospective comparative cohort analysis of 458 patients who received TKA at a regional private hospital between January 2016 and December 2018. Inclusion criteria included body mass index (BMI) <50 kg/m² and unilateral TKA. Using the patients' hospital records, age, gender, American Society of Anesthesiologists' score (ASA), BMI, diabetic status, length of stay (LOS), opioid requirement on discharge, range of motion (ROM) on discharge, return to theater, and readmission within 12 months were recorded. One hundred and thirty-eight patients received ACB and 263 did not. The two groups were comparable for age, gender, diabetic status, and ASA. Patients who received an ACB had an 18-hour longer LOS (p < 0.0001), but were discharged on lower dosages of opioids equivalent to 7.9 oral morphine milligram equivalent (MME; p < 0.0001). Patients who had an ACB had a similar ROM on discharge and did not have an increased rate of readmission or return to theater. This study demonstrates that ACB are efficacious when used as part of a multimodal analgesia regime for TKA.