Analgesic efficacy of infiltration between the popliteal artery and capsule of the knee (iPACK) block added to local infiltration analgesia and continuous adductor canal block after total knee arthroplasty: a randomized clinical trial

Abstract

BackgroundA combination of motor-sparing analgesia with local infiltration analgesia (LIA) and continuous adductor canal block (CACB) may improve postoperative pain and functional recovery for total knee arthroplasty (TKA). We hypothesized that the addition of a novel technique for posterior knee block, known as the infiltration between the popliteal artery and capsule of the knee (iPACK) block, to LIA with CACB would reduce opioid requirements.MethodsIn this double-blinded randomized controlled trial, 72 patients were assigned to receive either LIA with CACB (LIA+CACB group) or iPACK block with LIA and CACB (iPACK+LIA+CACB group). The primary outcome was cumulative postoperative intravenous morphine consumption within 24 hours. The secondary outcomes included numerical rating scale pain scores, incidence of posterior knee pain, performance test results, patient satisfaction, length of stay, and adverse events.ResultsMorphine consumption within 24 hours postoperatively showed no significant intergroup difference (LIA+CACB; 1.31±1.85 mg vs iPACK+LIA+CACB; 0.61±1.25 mg, p=0.08). There were no clinically significant differences in the overall pain scores between the groups. The lower Timed Up and Go test scores on postoperative days 1 and 2, along with a shorter duration of hospitalization, were found in the iPACK+LIA+CACB group (p<0.05).ConclusionThe addition of an iPACK block to the LIA and CACB does not reduce the postoperative opioid consumption nor improve analgesia. However, it may improve immediate functional performance and reduce the length of hospitalization after TKA.Trial registration numberTCTR20180702001.

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…”

“…Local anesthetic dosing regimen for iPACK blocks varied widely with three different types of local anesthetic medications utilized in included studies (ropivacaine, bupivacaine, and levobupivacaine). Five studies 25,26,[29][30][31] included epinephrine in the local anesthetic solution for the iPACK block. The most common formulation for iPACK was 0.25% levobupivacaine with epinephrine.…”