Periarticular Injection With or Without Adductor Canal Block for Pain Control Following Total Knee Arthroplasty.

Introduction: Periarticular injections (PAIs) have become a critical part of multimodal anesthetic regimens for total knee arthroplasty (TKA). This study assessed the effect of adductor canal blocks (ACBs) alone, periarticular injections (PAIs) alone, and the combination of both ACBs and PAIs on postoperative pain management in patients undergoing primary TKA. We hypothesized that there would be no significant difference in postoperative outcomes, including pain scores and narcotic use.

Methods: Patients who underwent primary TKA were retrospectively identified from February 2022 to February 2023. Patients were stratified based on perioperative local/regional anesthetic regimen (PAI only, PAI with an ACB, and ACB only) and matched in a 1:1:1 ratio. Patients were propensity score matched based on age, American Society of Anesthesiologists (ASA) score, body mass index (BMI), and preoperative narcotic usage. Patient demographics, as well as intra- and postoperative variables including narcotic refills, postoperative morphine requirements, pain scores, and readmissions, were compared. After successful matching, there were 40 patients in each cohort.

Results: First post-anesthesia care unit (PACU) visual analog pain scale (VAS) scores after surgery were not significantly different across all groups (P = 0.082). Pair-wise comparisons of patients receiving either PAI alone or ACB alone showed that patients receiving PAIs had lower narcotic usage at six hours (P = 0.037). A PAI alone also demonstrated a shorter length of stay compared to ACB alone (P = 0.001). Postoperative narcotics refills were similar between ACB only and PAI only (P = 0.056); however, PAI with an ACB had lower postoperative narcotic refills (P = 0.017). The rate of same-day physical therapy (PT) clearance was lowest in the ACB only group (37.5% [15 of 40]) (P = 0.002).

Conclusion: As hypothesized, there was no difference in pain scores immediately after surgery; however, postoperative morphine requirements at six hours, same-day physical therapy clearance, and length of stay were better in the PAI group. The use of PAIs may confer a benefit for both patients and healthcare systems as an adjunct to perioperative pain control.