IPACK Nerve Block for Total Knee Arthroplasty

Pain After Total Knee Arthroplasty: a Comparison of Combined Continuous Adductor Canal Block With Infiltration of Local Anesthetic Between the Popliteal Artery and Capsule of the Knee Block Versus Continuous Adductor Canal Block Alone on Postoperative Analgesia

Double-blind, randomized controlled clinical trial to test the efficacy of IPACK on postoperative opioid consumption, patient satisfaction, pain scores, mobility, and several other secondary outcomes in adults undergoing primary unilateral TKA. Enrolled patients will be randomized to either continuous ACB with IPACK or to continuous ACB with sham subcutaneous saline injection. Outcomes assessors and patients will be blinded to the intervention.

Only the regional anesthesiologist performing the block will know the randomization status. The study participants, outcome assessors/researchers, other anesthesia personnel, surgeons, physician assistants, and nurses will be blinded to the treatment arm.

ACB bolused with 20 ml of ropivacaine 0.25% with 1:300,000 epinephrine followed by an 8 ml/hr continuous infusion of ropivacaine 0.2% and IPACK block with 20 ml of ropivacaine 0.25% with 1:300,000 epinephrine

ACB bolused with 20 ml of ropivacaine 0.25% with 1:300,000 epinephrine followed by an 8 ml/hr continuous infusion of ropivacaine 0.2% and a sham IPACK block with subcutaneous saline injection along the medial thigh

All patients will receive sedation with midazolam and/or fentanyl titrated to comfort during block procedures. Per our standard practice at Ochsner Medical Center, all patients will have either spinal or combined spinal-epidural anesthesia with mepivacaine 1.5% as the primary anesthetic during the surgery and sedation with propofol titrated to comfort. Also per our standard practice at Ochsner Medical Center, multimodal therapy will include ketamine 0.25mg/kg IV (up to 50mg) intraoperatively, dexamethasone 8mg IV intraoperatively, pregablin 150mg PO preoperatively (adjusted to 75mg for age over 70) followed by 75mg nightly (or home gabapentin dose), acetaminophen 1000mg IV followed by 100mg PO every 6 hours postoperatively, and celecoxib 400mg PO on POD #0 followed by 200mg PO daily.

All patients will receive sedation with midazolam and/or fentanyl titrated to comfort during block procedures. Per our standard practice at Ochsner Medical Center, all patients will have either spinal or combined spinal-epidural anesthesia with mepivacaine 1.5% as the primary anesthetic during the surgery and sedation with propofol titrated to comfort. Also per our standard practice at Ochsner Medical Center, multimodal therapy will include ketamine 0.25mg/kg IV (up to 50mg) intraoperatively, dexamethasone 8mg IV intraoperatively, pregablin 150mg PO preoperatively (adjusted to 75mg for age over 70) followed by 75mg nightly (or home gabapentin dose), acetaminophen 1000mg IV followed by 100mg PO every 6 hours postoperatively, and celecoxib 400mg PO on POD #0 followed by 200mg PO daily.

Patient satisfaction on day of discharge using the Brief Pain Inventory (BPI) or a similar validated satisfaction survey

Inclusion Criteria: Unilateral, primary tricompartment total knee arthroplasty Age 18 years or older ASA I-III Eligible for spinal or combined spinal epidural anesthetic Able to speak, read, and understand English Willing to participate in the trial Exclusion Criteria: Contraindication to regional anesthesia or peripheral nerve blocks Allergy to local anesthetics Allergy to NSAIDs Chronic renal insufficiency with Cr > 1.4 or GFR < 60 Have chronic pain that is not related to their knee joint Have been using opioids on a chronic basis (daily or almost daily opioid use for 3 months or longer) Have a pre-existing peripheral neuropathy involving the operative site Body mass index greater than or equal to 40