Periarticular Injection Alone Provides Comparable Early Recovery to Combined Adductor Canal and Infiltration between the Popliteal Artery and Capsule of the Knee Blocks Following Total Knee Arthroplasty: A Prospective Randomized Trial.

Abstract

The relative effectiveness of commonly used regional anesthesia techniques, including adductor canal block (ACB) and infiltration between the popliteal artery and capsule of the knee (IPACK), compared with periarticular injection (PAI) alone in total knee arthroplasty (TKA) remains unclear. In this prospective, randomized, patient-blinded trial, 140 patients undergoing primary TKA were randomized to receive either preoperative regional blocks (ACB plus IPACK) combined with intraoperative PAI (n = 70) or intraoperative PAI alone (n = 70). All patients received an identical total dose and composition of local anesthetic (80 mL of 0.25% bupivacaine with epinephrine and 30 mg ketorolac). Daily remote patient monitoring was performed for two weeks preoperatively and two weeks postoperatively to assess visual analog scale (VAS) pain scores, opioid consumption (morphine milligram equivalents [MME]), Oxford Knee Scores (OKS), step counts, and patient satisfaction. Linear mixed models and appropriate comparative tests were used for analysis. An a priori power analysis determined that 70 patients per group were required to detect a VAS pain difference of greater than 1.0. Pain scores peaked on postoperative day three in both groups and declined thereafter. The PAI-only group reported slightly lower VAS pain on postoperative day 1 (3.3 versus 3.9; mean difference -0.6; P = 0.025), although this difference did not meet the threshold for clinical significance; no other between-group differences were observed. Opioid consumption, OKS, step counts, and patient satisfaction with pain control, activity level, and range of motion were similar between groups throughout the study period. In patients undergoing primary TKA, intraoperative PAI alone produced outcomes comparable to combined ACB plus IPACK and PAI through the first fourteen postoperative days. These Level I findings, captured using high-frequency remote patient monitoring, suggest that routine use of multiple regional blocks may not provide clinically meaningful additional benefit within contemporary multimodal pathways.