iPACK Block and Adductor Canal Catheter vs Adductor Canal Catheter for Total Knee Arthroplasty: A Randomized Controlled Trial

Background: Regional anesthetic techniques including the adductor canal catheter (ACC) have aided management of post-operative pain for total knee arthroplasty (TKA). The interspace between the popliteal artery and posterior capsule of the knee (iPACK), has been introduced to address posterior knee pain that is not well covered by the ACC. Studies have looked at the addition of the iPACK block to subjects who received an ACC with and without periarticular local infiltration with varying results. We hypothesized that adding the iPACK block to subjects who also received an ACC and periarticular injection (PAI) would significantly decrease opioid consumption compared to the ACC alone in TKA. Methods: Sixty subjects were randomized to receive an ACC alone (control group) or ACC plus single shot iPACK block (iPACK group) for TKA. All subjects were operated on by the same surgeon and received the same PAI. For the primary outcome of postoperative pain, we used opioid consumption as measured by morphine milligram equivalent (MME). Secondary outcomes included pain scores determined by the visual analog scale (VAS), distance ambulated, time to physical therapy (PT) and length of hospital stay. Results: We did not observe a significant difference between groups for opioid consumption, pain scores, distance ambulated (p > 0.05 across all time points), length of hospital stay (p = 0.64), or time to PT (p = 0.32). Conclusion: When combined with an ACC and PAI, the iPACK block did not significantly decrease opioid consumption, pain scores, time to first PT session or increase distance ambulated.