Intraoperative Direct vs Postoperative Ultrasound Guided Adductor Canal Nerve Block After Total Knee Arthroplasty

Intraoperative Direct vs Postoperative Ultrasound Guided Adductor Canal Nerve Block After Total Knee Arthroplasty

Intraoperative Direct Adductor Canal Nerve Block Versus Post Operative Ultrasound Guided Adductor Canal Nerve Block in Total Knee Arthroplasty: a Double-blind Randomized Trial

This study compares analgesic effect between two techniques of adductor canal nerve block after total knee arthroplasty. The first group of the patients will receive intraoperative adductor canal nerve block; and the other group post operative ultrasound guided adductor canal nerve block. Investigators will measure postoperative opioid consumption, pain management and rehabilitation goals.

Total knee arthroplasty (TKA) is a successful alternative to treat late stage knee osteoarthritis (OA). Pain management has been one of the main focuses of postoperative care. Most surgeons prefer a comprehensive multimodal approach including preoperative pharmacological treatment, intraoperative infiltration with complex drug mixes and postoperative peripheral nerve block. The most common postoperative nerve block alternative is the proximal femoral nerve block (FNB) which has shown improvements on postoperative pain measured by reduced opioid consumption and decreased pain at rest. Its main detractors argue that the motor nerve block effect is deleterious to early ambulation and have promoted adductor canal nerve blocks (ACB). Described by Lund et al in 2011, ACB block main femoral pain sensory contributors to the knee (articular branches of obturator nerve, vastus medialis branch and saphenous nerve) but is more distal to most motor branches to the quadriceps allowing near to normal quadriceps strength. Standard ACB block is performed under ultrasound guidance after surgery completion, still in the operating room (OR). Recent literature has shown the anatomic feasibility of intraoperative ACB via blunt suprapatellar dissection in standard medial parapatellar TKA approaches. The study seeks to determine the effectiveness of standard ultrasound guidance ACB compared with intraoperative ACB.

Total blind (patient, physicians, outcome assessors and statistician) Closed envelope by independent randomizer is given to physician assistant. The assistant prepares randomly allocated placebo or local anesthetic. Group is coded so that statistician is also blind

Before skin closure, blunt suprapatellar dissection proximal to medial femoral condyle towards adductor canal. Nerve block at this level with 20ml of Bupivacaine 0.25%. Postoperatively, mid-thigh ultrasound guided standard adductor canal nerve block with 20ml of saline solution (NaCl 0.9%).

Before skin closure, blunt suprapatellar dissection proximal to medial femoral condyle towards adductor canal. Nerve block at this level with 20ml of of saline solution (NaCl 0.9%). Postoperatively, mid-thigh ultrasound guided standard adductor canal nerve block with 20ml Bupivacaine 0.25%.

Patient reported pain scale using visual analog scale (VAS) every 6 hours after surgery (0 hours, 6 hours, 12 hours, 18 hours and 24 hours)

Time between surgery and patient in conditions for discharge: no IV requirements, basic walking capability and VAS pain score equal or below 3

Inclusion Criteria: Primary total knee arthroplasty Unilateral American Society of Anesthesiologists (ASA) score I, II or III Accepts spinal anesthesia Exclusion Criteria: General anesthesia Chronic kidney disease Drug or alcohol abuse Chronic opioid use Allergic to bupivacaine or similar