Abstract
Objectives:
In an effort to reduce reliance on opioid analgesics, an increased emphasis has been placed on peripheral nerve blocks for pain control following ACL reconstruction. The commonly used adductor canal block may provide inadequate post-operative analgesia, as it spares sensory function to the posterior aspect of the knee. This region can be specifically targeted using an IPACK (Interspace Between the Popliteal Artery and the Capsule of the Posterior Knee) block potentially leading to improved pain control. The purpose of the current study was to compare clinical outcomes of an isolated standard adductor canal block versus combined ACB and IPACK blocks with respect to level of post-operative pain, opioid consumption, and satisfaction in patients undergoing ACL reconstruction using a bone-patellar tendon-bone (BPTB) autograft.
Methods:
We prospectively recruited patients undergoing ACL reconstruction with BPTB autograft at a single institution. Subjects were randomized pre-operatively to either control or experimental groups using a pre-established block randomization and were blinded to their treatment group. Patients in the control group received the standard-of-care ACB consisting of 15-ml of Bupivacaine (0.25%). Patients in the experimental group received 20-ml of Bupivacaine (0.25%) injected into the interspace between the popliteal artery and capsule of the knee in addition to the 15-ml Bupivicaine ACB. Post-operative pain level, pain control, and pain satisfaction were collected at 24hrs, 48hrs, 72hrs and one week postoperatively. Satisfaction with pain control was assessed using a 0-10 numeric scale with 0 equal to not satisfied and 10 equal to completely satisfied. Pain level was measured using a Visual Analog Scale (VAS) from no pain to extreme pain. The type and quantity of pain medications including 325-5 mg Percocet, Tylenol, and other pain medications were recorded at each time point. Variables were assessed using Shapiro-Wilks test for normality and T-test or non-parametric tests for continuous variables and Chi-squared tests for categorical variables.
Results:
A total of 20 patients were preliminarily analyzed with all patients having at least 1 week of post-operative follow-up. The mean age of the cohort was 28.75 ± 9.15 years, mean body mass index (BMI) was 24.0 ± 4.82 kg/m2 and 55% (n=11) were Male. The two arms consisted of 12 patients randomized to the control arm and 8 to the experimental arm. There were no statistically significant differences between the groups with respect to age, BMI, or sex (p > 0.05). Patients who received the IPACK block had significantly higher satisfaction with pain control at 24hrs post-operatively compared to those who did not (7.62 vs. 5.25, p=0.01). Patients who received the IPACK block used less total number of prescribed opioids tablets than those in the control arm (8.5 vs. 11.15, p=0.52), and had less pain at 24 hours (51.12 vs. 65.17, p=0.24) and 48 hours (51.00 vs. 57.92, p=0.55). (Table 1)
Conclusions:
Patients who received combined IPACK and ACB blocks exhibited better pain control and higher satisfaction with their care compared to those who received the standard-of-care ACB alone following ACL reconstruction using autograft tissue.
