Peripheral Nerve Blocks Linked to Less Pain, Fewer Opioids in Patients Undergoing TKA

    One of the postop goals of orthopaedic surgeons is to ensure their total knee arthroplasty (TKA) patients have good pain control without reliance on opioids. With the increase in the number of TKAs being performed as outpatient procedures, as well as the rise in enhanced recovery and fast-track protocols, surgeons are particularly interested in strategies that will allow them to discharge patients in a timely manner while avoiding readmission for pain management.

    At the 2018 World Congress on Regional Anesthesia and Pain Medicine, surgeons and anesthesiologists from Hospital for Special Surgery in New York presented one such strategy: the use of motor-sparing peripheral nerve blocks (specifically, adductor canal block [ACB]) and interspace between the popliteal artery and capsule of the posterior knee (IPACK) block plus periarticular injection (PAI) to allow early ambulation without significant pain to facilitate rehabilitation.

    Their double-blinded randomized controlled trial included 86 TKA patients who were randomized to 1 of 2 groups:

    • PAI alone (control group, n=43)
    • IPACK with ACB and a modified PAI injection (intervention group, n=43)

    As a primary outcome, the researchers assessed pain on ambulation on POD1, with secondary outcomes of numeric rating scale (NRS) pain scores, pain outcomes, and opioid consumption.

    They found that patients in the intervention group had less postoperative pain, lower opioid consumption, and greater satisfaction after surgery than patients in the control group. Compared with the control group, patients in the intervention group had:

    • Lower NRS pain scores on ambulation on POD0, POD1, and POD2: 1.7 vs 5.2, P< 0.001 on POD0; 1.7 vs 5, P<0.001 on POD1; and 4.5 vs 5.5, P = 0.025 on POD2
    • Lower NRS pain scores after physical therapy on POD0 and POD1 (P< 0.001 for both)
    • Fewer periods of severe pain in a 24-hour period (2.6% vs 16.5% on POD1)
    • Lower opioid consumption in the PACU (P=0.002), less intravenous opioid use (P<0.001), and less use of intravenous patient-controlled analgesia (P=0.017)

    Although not statistically significant, more patients in the intervention group were discharged on POD0 (5%) and POD1 (19%) than in the control group (0 on POD0 and 16% on POD1).

    The study received 1 of 3 “Best of Meeting Abstract Awards” from the American Society of Regional Anesthesia and Pain Medicine.


    Kim D, Yi L, Beathe J, et al. The addition of ACB and IPACK to PAI enhances postoperative pain control in TKA: a randomized controlled trial. Presented at the 2018 World Congress on Regional Anesthesia and Pain Medicine, April 19-21, New York, New York.


    The study authors have no disclosures relevant to their presentation.