Single shot adductor canal block combined with intravenous patient-controlled analgesia can be effective as continuous adductor canal block in reducing opioid consumption and breakthrough pain after total knee arthroplasty

Purpose: The aim of this study was to compare the following three analgesic methods after Total knee arthroplasty (TKA): intravenous patient-controlled analgesia (IV-PCA), continuous adductor canal block (C-ACB), and intravenous patient-controlled analgesia combined with single shot adductor canal block (PCA + sACB). Methods: Records of 482 patients undergoing primary TKA from September 2019 to September 2020 were analyzed. Patients were divided into three pain control groups: IV-PCA (n = 180), C-ACB (n = 173) and PCA + sACB (n = 129). Single shot adductor canal block was performed 24 h after surgery in the PCA + sACB group. Rescue opioid consumption, breakthrough pain, pain numerical rating scale (NRS), and anti-emetics administration were measured from postoperative day (POD) 1 to POD 5. Results: Rescue opioid consumption was less in C-ACB or PCA + sACB group than in the IV-PCA group at POD1 (p < 0.001 and p = 0.002, respectively). Patients in C-ACB and PCA + sACB groups had less breakthrough pain (NRS > 5) than the IV-PCA group at POD1 (p = 0.007). On POD2, C-ACB was statistically superior to IV-PCA (p = 0.011) in terms of breakthrough pain. Postoperative pain NRS was lower in the C-ACB and PCA + sACB groups than in the IV-PCA group (p = 0.025 and p = 0.019, respectively). The total number of anti-emetics consumption was lower in C-ACB and PCA + sACB groups than in the IV-PCA group (p = 0.003 and p = 0.002, respectively). Conclusion: PCA + sACB not only reduced patients’ need for rescue opioids, but also decreased the number of breakthrough pain and anti-emetics compared to IV-PCA in early postoperative days after TKA. However, C-ACB and PCA + sACB did not differ significantly in analgesic efficacy or opioid-related side effects. PCA + sACB can be as effective as C-ACB for patients undergoing TKA. Level of evidence: Retrospective cohort study, level III.