Regional anesthesia is commonly utilized to minimize postoperative pain, improve function, and allow earlier rehabilitation following Total Knee Arthroplasty (TKA). The adductor canal block (ACB) provides effective analgesia of the anterior knee. However, patients will often experience posterior pain not covered by the ACB requiring supplemental opioid medications. A technique involving infiltration of local anesthetic between the popliteal artery and capsule of knee (IPACK) targets the terminal branches of the sciatic nerve, providing an alternative for controlling posterior knee pain following TKA. IRB approval was obtained, a power analysis was performed, and all patients gave informed consent. Eligible patients were those scheduled for an elective unilateral, primary TKA, who were ≥ 18 years old, English speaking, American Society of Anesthesiologists physical status (ASA PS) classification I-III. Exclusion criteria included contraindication to regional anesthesia or peripheral nerve blocks, allergy to local anesthetics, allergy to nonsteroidal anti-inflammatory drugs (NSAIDs), chronic renal insufficiency with GFR < 60, chronic pain not related to the operative joint, chronic (> 3 month) opioid use, pre-existing peripheral neuropathy involving the operative limb, and body mass index (BMI) ≥ 40 kg/m2. Patients were randomized into one of two treatment arms: Continuous ACB with IPACK (IPACK Group) block or Continuous ACB with sham subcutaneous saline injection (No IPACK Group). IPACK Group received single injection of 20 mL 0.25% Ropivacaine. Postoperatively, all patients received a standardized multimodal analgesic regimen. The study followed a double-blinded format. Only the anesthesiologist performing the block was aware of randomization status. Following surgery, a blinded medical assessor recorded cumulative opioid consumption, average and worst pain scores, and gait distance.Introduction
Materials and Methods
