Purpose: The infiltration between the popliteal artery and the capsule of the posterior knee (iPACK) has been described to provide analgesia without loss of muscle strength and is effective in functional recovery. This study compared iPACK + ACB (adductor canal block) with PAI (periarticular infiltration) + ACB and ACB alone in terms of postoperative analgesia and functional improvement.
Methods: This double-blinded randomized controlled trial included 105 patients undergoing unilateral total knee arthroplasty. Patients received ACB, iPACK + ACB, and PAI + ACB along with spinal anesthesia. The primary outcome was the area under the curve (AUC) numeric rating scale (NRS) at 48 h. Secondary outcomes were cumulative postoperative analgesic consumption within 48 h, timed up-and-go test, range of motion, length of hospital stay, patient satisfaction, and adverse events.
Results: The 48-h AUC movement NRS score in the iPACK + ACB group was significantly lower than in the PAI + ACB and ACB groups (p < 0.05). At the postoperative 48th h, the opioid consumption of the iPACK + ACB group was lower than those of the ACB and PAI + ACB groups (p < 0.001). The patients in the iPACK + ACB group had significantly shorter discharge and mobilization days than the ACB and PAI + ACB groups (p < 0.001).
Conclusions: The adding of an iPACK block to the ACB improves postoperative analgesia and reduces opioid consumption. In addition, this approach improves functional performance and reduces hospital stay.
Keywords: Adductor canal block; Periarticular block; Total knee arthroplasty; iPACK.
© 2022. The Author(s) under exclusive licence to Japanese Society of Anesthesiologists.