Analgesic efficacy of adding the IPACK block to a multimodal analgesia protocol for primary total knee arthroplasty

Abstract

Background and objectivesPeripheral nerve blocks have been integrated into most multimodal analgesia protocols for total knee arthroplasty (TKA). The adductor canal block (ACB) has gained popularity because of its quadriceps muscle sparing. Similarly, local anesthetic injection between the popliteal artery and the posterior capsule of the knee, IPACK block, has been described to provide analgesia to the posterior capsule of the knee with motor-sparing qualities. This prospective randomized controlled trial aimed to assess the analgesic efficacy of adding the IPACK block to our current multimodal analgesic regimen, including the ACB, in patients undergoing primary TKA.Methods119 patients were randomized to receive either an IPACK or a sham block in addition to multimodal analgesia and an ACB. We were set to assess pain in the back of the knee 6 hours after surgery. Other end points included quality of recovery after surgery, pain scores, opioid requirements, and functional measures.ResultsPatients who received the IPACK block had less pain in the back of the knee 6 hours after surgery when compared with the sham block: 21.7% vs 45.8%, p<0.01. There was marginal improvement in other pain measures in the first 24 hours after surgery. However, opioid requirements, quality of recovery and functional measures were similar between the two groups.ConclusionThe IPACK block reduced the incidence of posterior knee pain 6 hours postoperatively.

Ultrasound-Guided Local Anesthetic Infiltration Between the Popliteal Artery and the Capsule of the Posterior Knee (IPACK) Block for Primary Total Knee Arthroplasty: A Systematic Review of Randomized Controlled Trials

“…The search strategy identified 2180 unique citations. After independent and duplicate screening by two authors (RSD and BL), eight RCTs 13,[25][26][27][28][29][30][31] were identified that fulfilled eligibility criteria. Collectively, these eight RCTs consisted of 777 patients (377 patients received the iPACK block; 400 patients in the control cohort received another modality of peripheral nerve blockade or PAI for knee analgesia).…”

“…Bias assessment for all included studies is summarized in Figure 2. All eight RCTs 13,[25][26][27][28][29][30][31] generally demonstrated a low risk of bias in random sequence generation and allocation concealment, blinding of outcome assessment, incomplete outcome data, and selective reporting. In terms of blinding of participants, some RCTs 13,25,26 displayed a high risk for bias because although they blinded all surgeons, recovery room and floor nurses, research assistants, statisticians, and patients, it was impossible to blind the anesthesiologist performing the ultrasound-guided iPACK block who may have participated in the study.…”

“…Other sources of bias included no true control group without a posterior knee block, and unequal dose of local anesthetic between study arms. For the primary anesthetic, five studies 13,25,28,29,31 administered neuraxial anesthesia, two studies 26,27 either administered general anesthesia or neuraxial anesthesia per the discretion of the primary anesthesia team, and one study administered general anesthesia only. 30 All RCTs excluded patients who had a history of chronic pain or utilized preoperative opioids.…”

“…30 All RCTs excluded patients who had a history of chronic pain or utilized preoperative opioids. 13,[25][26][27][28][29][30][31] Local and Regional Anesthesia 2021:14 https://doi.org/10.2147/LRA.S303827…”

“…25,29,31 Volume of injectate ranged from 20 mL to 25 mL, with the most common being 20 mL in seven studies. [25][26][27][28][29][30][31] Primary Outcome #1: Postoperative Opioid Consumption Data on postoperative opioid consumption either in the PACU or on postoperative day (POD) #0 were reported in seven RCTs 13,[25][26][27][29][30][31] comprising a total of 606 patients (Table 3). Compared to controls, patients who received an iPACK block consumed less opioid in the PACU or POD #0 in two 13,30 of seven studies, consumed more opioid in one 29 of seven studies, while the remaining studies [25][26][27]31 demonstrated no significant differences.…”