Total knee arthroplasty (TKA) has been associated with chronic opioid use and postoperative pain that prevents early mobility and prolongs hospital stay. We hypothesized that combined single-shot infiltration between popliteal artery and capsule of the knee (IPACK) and adductor canal blockade (ACB) with bupivacaine, dexmedetomidine and dexamethasone (dex-dex) provides better postoperative pain management compared to ACB alone for patients undergoing unilateral TKA.
This retrospective cohort study included adult patients who underwent primary, unilateral TKA. Patients were separated into two cohorts: single-shot ACB alone (bupivacaine 0.25% only) and single-shot IPACK+ACB with dex-dex . Patients were propensity-matched 1:1. The primary study outcome was total opioid consumption converted to morphine milligram equivalents (MME) per eight-hour interval and postoperative day. Secondary outcomes included daily patient-reported pain scores, length of stay, ambulation distance, return to emergency department (ED), hospital readmission and 30-day adverse events. Postoperative outcomes were analyzed and compared between cohorts utilizing chi-squared and t-tests.
One-hundred eighty patients were identified, of which propensity matching used 71% of the set to yield 64 with IPACK+ACB (65 years, 24% male, BMI 32.5) and 64 with ACB only (64 years, 22% male, BMI 32.0). IPACK+ACB group had significantly lower total summative MME throughout entire postoperative stay (160.1 vs 268.8, p=0.002) and cumulatively after the first 24 hours (53.2 vs 100.8, p<0.001). IPACK+ACB also had lower mean VAS scores for 0-8 hours (4.34 vs 5.51, p=0.005) and 8-16 hours (4.62 vs 5.69, p=0.009) after the operation. There were no significant differences in anesthesia-related or surgery-related complications, ambulation distance, length of stay, return to ED, or hospital readmission between cohorts.
Combined single-shot IPACK+ACB with dexmedetomidine and dexamethasone was associated with lower total narcotic intake and mean VAS scores during most of the immediate postoperative period following primary, unilateral TKA compared to ACB alone. Implementing longer acting, single-shot IPACK+ACB for TKA can balance elective and more selective pain management with early rehabilitation.