Adductor Canal Blocks Reduce Inpatient Opioid Consumption While Maintaining Noninferior Pain Control and Functional Outcomes After Total Knee Arthroplasty

The use of perioperative adductor canal blocks (PABs) continues to be a highly debated topic for total knee arthroplasty (TKA). Here, we evaluate the effect of PABs on immediate postoperative subjective pain scores, opioid consumption, and objective functional outcomes.

On December 1, 2019, an institution-wide policy change was begun to use PABs in primary elective TKAs. Patient demographics, immediate postoperative nursing documented pain scores, opioid administration events, and validated physical therapy functional scores were prospectively collected as part of the standard of care and retrospectively queried through our electronic data warehouse. A historical comparison cohort was derived from consecutive patients undergoing TKA between July 1, 2019 and November 30, 2019.

405 primary TKAs received PABs, while 789 patients were in the control cohort. Compared with controls, average verbal rating scale pain scores were lower among PAB recipients from 0-12 hours (2.42 ± 1.60 vs 2.05 ± 1.60; <.001) and 24-36 hours (4.92 ± 2.00 vs 4.47 ± 2.27; <.01). PAB recipients demonstrated significantly lower opioid consumption within the first 24 hours (44.34 ± 40.98 vs 36.83 ± 48.13; P < .01) and during their total inpatient stay (92.27 ± 109.81 vs 77.52 ± 123.11; <.05). AM-PAC scores within the first 24 hours were also higher for PABs (total scores: 20.28 ± 3.06 vs 20.71 ± 3.12; <.05).

While the minimal clinically important differences in pain scores and functional status were comparable between both cohorts, patients demonstrated a significant reduction in overall inpatient opiate consumption after the introduction of PABs. Surgeons should consider these findings when evaluating for perioperative pain management, opioid-sparing, and rapid discharge protocols.