Postoperative Pain and Opioid Usage With Combined Adductor Canal and IPACK Block Versus Isolated Adductor Canal Block After Anterior Cruciate Ligament Reconstruction With a Bone-Patellar Tendon-Bone Autograft: A Single-Center Randomized Controlled Trial.

Background: Efforts to decrease pain, improve early rehabilitation, and reduce opioid consumption have prompted a focus on peripheral nerve blocks for pain management after anterior cruciate ligament reconstruction (ACLR). The commonly used adductor canal block (ACB) might not provide sufficient postoperative pain control because of its lack of coverage of the posterior aspect of the knee. The addition of the IPACK (interspace between the popliteal artery and the capsule of the posterior knee) block, which targets this area, to the standard ACB could potentially provide better pain control after ACLR over the current standard of care.

Purpose/hypothesis: The purpose of this study was to compare and analyze postoperative pain, satisfaction, and opioid demand between the standard ACB and a combination of an ACB and IPACK block in patients undergoing ACLR with a bone-patellar tendon-bone (BTB) autograft. It was hypothesized was that the addition of the IPACK block would substantially improve early postoperative pain control and minimize opioid use.

Study Design: Randomized controlled trial; Level of evidence, 2.

Methods: A total of 102 patients undergoing ACLR with a BTB autograft at a single institution were recruited. Patients were randomly assigned to receive either the ACB alone or the ACB plus IPACK block. Patients were contacted at 24 hours (postoperative day [POD] 1), 48 hours (POD 2), 72 hours (POD 3), and 1 week to assess postoperative pain scores, opioid consumption, and satisfaction with their postoperative pain control. Intergroup comparative analysis was performed using a test or nonparametric test for continuous variables and the chi-square test for categorical variables. Opioid usage was reported as morphine milligram equivalents (MME).

Results: The final analysis included 96 patients, with 47 in the control group (ACB) who received only the ACB and 49 in the experimental group (IPACK) who received the ACB and an additional IPACK block. The cohort was composed of 60.4% male patients with a mean age of 28.40 ± 7.51 years (range, 18-55 years) and a mean body mass index of 25.67 ± 4.84 kg/m. There were no statistically significant differences between the groups with respect to age, body mass index, or sex ( > .05). Patients in the IPACK group reported significantly lower opioid usage than those in the ACB group on POD 1 (mean, 6.1 [interquartile range (IQR), 4.5-7.7] vs 10.7 [IQR, 8.6-13.0] MME, respectively; < .001), POD 2 (mean, 7.3 [IQR, 5.2-9.5] vs 12.5 [IQR, 10.0-15.0] MME, respectively; = .001), and POD 3 (mean, 4.2 [IQR, 2.8-5.5] vs 9.4 [IQR, 7.1-12.0] MME, respectively; < .001). The visual analog scale for pain score on POD 1 (mean, 67.7 [IQR, 62.0-73.0] vs 55.2 [IQR, 48.0-63.0], respectively; = .024) and POD 3 (mean, 54.9 [IQR, 48.0-63.0] vs 44.4 [IQR, 37.0-51.0], respectively; = .037) was statistically higher in the ACB group compared with the IPACK group. On POD 1, patient satisfaction was higher in the IPACK group than in the ACB group (mean, 7.3 [IQR, 6.6-8.0] vs 5.6 [IQR, 4.8-6.4], respectively; = .001). No statistically significant differences were observed between groups on POD 7. On regression analysis, IPACK block (β = -13.0; = .03) and male sex (β = -9.9; = .024) were significant negative predictors for opioid use on POD 1. The association of reduced opioid use in the IPACK group persisted on POD 2 (β = -12.0; = .019) and POD 3 (β = -15.0; < .001).

Conclusion: The results of this study suggest that the addition of an IPACK block to an ACB leads to reduced opioid consumption, improved pain control, and higher satisfaction with pain control acutely after ACLR with a BTB autograft.

Registration: NCT05286307 (ClinicalTrials.gov).