Abstract
Adductor canal blocks (ACBs) reduce postoperative pain and opioid consumption for patients undergoing total knee arthroplasty (TKA); however, whether the optimal timing of the placement is pre-operatively or immediately post-operatively remains unclear. The postoperative placement of an adductor canal block was hypothesized to have more favorable outcomes.
From September 2023 to January 2024, patients undergoing TKA with one of two surgeons were randomized to the experimental (postoperative) or control (preoperative) group. Clinical staff were blinded. Blocks utilized 20 mL Ropivacaine 0.2%. All other institutional protocols remained unchanged. Pain (visual analog scale), opioids consumed (morphine milligram equivalents), nausea, and vomiting were recorded at two and 24 hours post-tively. Length of stay and demographics (sex, age, laterality, body mass index, and anesthesia modality) were collected. Priori power analysis demonstrated a need for 70 total patients. Mann-Whitney U- and Fisher's exact tests were utilized. The study was registered on clinicaltrials.gov (NCT05974501) and Institutional Review Board approved. Of 111 patients, 76% agreed to participate (47 pre-operative and 37 post-operative). There were no differences in demographics.
There were no differences between groups at two or 24 hours for pain, opioid consumption, patients who had nausea, and patients who had vomiting. No differences for length of hospital stay were observed for hours, nights, or the number of same-day or next-day discharges. An ACB for TKA performed preoperatively versus postoperatively did not affect patient postoperative pain, opioid consumption, nausea, vomiting, or length of stay.
Preoperative logistics can be streamlined by having the option to place the ACB preoperatively or immediately postoperatively without concern for effects on patient pain, opioid consumption, or length of stay.