The effect of adductor canal block on outcomes of total knee arthroplasty: A single centre, historical cohort study.

Background: Adductor canal blocks (ACBs) have been associated with reduced pain following total knee arthroplasty (TKA). There is a paucity of evidence regarding whether these early differences impact longer term outcomes. This study aimed to identify whether using ACB in TKA was associated with improvements in both early and late outcomes. Methods: Patients who underwent a unilateral TKA between 2021 and 2022 were retrospectively assessed for pain scores, time to first mobilization and opioid use over the first 72 h. At 6 weeks, complications, pain scores and opioid use were assessed. At 12 months validated patient reported outcome measures (PROMs) and patient satisfaction with their surgery were assessed. Results: 262 unilateral TKA, of whom 129 received ACB (ACB group) and 133 did not (control group) were assessed. The ACB group had significantly lower median day 1 pain (median difference -0.44 (-0.09 to -0.79), p = 0.015). There was no significant difference between groups for pain after 24 h, time to mobilization or opioid use over 72 h. There was no significant difference in pain (p = 0.892), opioid use (p = 0.913) or complications (p = 0.348) at 6 weeks, or median change in PROMs (p = 0.436 and p = 0.307), opioid use (p = 0.187), or satisfaction with surgery (p = 0.262) at 12 months. Conclusion: ACBs were associated with a clinically insignificant difference in median pain on day 1. there was no association with pain after 24 h, opioid use, time to mobilization or longer term outcomes. Our findings do not support the use of routine ACB during TKA.