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
Knee osteoarthritis is a leading cause of disability around the world. Traditionally, total knee arthroplasty (TKA) is the gold standard treatment; however, unicompartmental knee arthroplasty (UKA) has emerged as a less-invasive alternative to TKA. Patients with UKAs participate earlier with physical therapy (PT), have decreased complications, and faster discharges (1, 2). As UKA has evolved, so has computer navigation and robotic technology. The Robotic Assisted UKA combines the less invasive approach of the UKA with accurate and reproducible alignment offered by a robotic interface (3)(Figure1). A key part of a patient's satisfaction is perioperative pain control. Femoral nerve blocks (FNB) are commonly performed to provide analgesia, though they cause quadriceps weakness which limits PT (4). An alternative is the adductor canal block (ACB) which provides analgesia while limiting quadriceps weakness (4). The adductor canal is an aponeurotic structure in the middle third of the thigh containing the femoral artery and vein, and several nerves innervating the knee joint including the saphenous nerve, nerve to the vastus medialis, medial femoral cutaneous nerve, posterior branch and occasionally the anterior branch of the obturator nerve (5). In a multi-modal approach with Orthopedic Surgery, Regional Anesthesia, and PT departments, an early goal directed plan of care was developed to study ACB in UKA with a focus on analgesia effectiveness and PT compliance rates. Following IRB approval, we performed a case series including 29 patients who received a single shot ACB. Primary outcomes were distance walked with PT on postoperative day (POD) 0 and 1 and discharge day. Our secondary outcomes included Visual Analog Scale (VAS) scores in the post-anesthesia care unit (PACU), 8 and 24 hours postoperatively and oral morphine equivalents required for breakthrough pain.Introduction
Methods
