Adductor Canal Block Combined With IPACK Block for Postoperative Analgesia After Total Knee Arthroplasty: A Retrospective Cohort Study

Background: There is no consensus on whether adductor canal block (ACB) combined with infiltration between the popliteal artery and capsule of the posterior knee (IPACK) block can further increase analgesia and reduce opioid consumption after total knee arthroplasty (TKA) compared with ACB and periarticular infiltration analgesia (PIA). Purpose: This study aimed to evaluate the effectiveness of combining ACB and PACK block on analgesia and functional recovery following TKA. Methods: A retrospective cohort study was conducted involving 386 patients who underwent primary unilateral TKA at our institution from January 2020 to October 2022. Patients were divided into 3 groups and treated with PIA, ACB, or ACB combined with IPACK block, respectively. Primary outcomes were postoperative morphine consumption and visual analogue scale (VAS) pain scores. Secondary outcomes included functional recovery, evaluated by knee range of motion, quadriceps strength, daily mobilization distance, and postoperative length of stay. Other outcomes included incidence of complications. Results: Patients in the ACB + IPACK group had significantly less morphine consumption on postoperative day 1 and during hospitalization than patients in the PIA and ACB groups. Furthermore, the ACB + IPACK group had significantly lower VAS scores at rest and during motion at 6, 12, and 24 hours postoperatively (but not at other time points), better knee range of motion on postoperative days 1 and 2 (but not day 3), and a greater daily mobilization distance on postoperative day 1 (but not days 2 and 3). The ACB + IPACK group had significantly lower incidences of postoperative nausea and vomiting than the PIA and ACB groups. Conclusion: This retrospective cohort study suggests that a combination of ACB and IPACK block may have a greater effect than PIA or ACB alone on analgesia following TKA, while providing better functional recovery. Further study is warranted.