Analgesia After Total Knee Arthroplasty

Analgesia After Total Knee Arthroplasty: Randomized Controlled Trial Comparing (a) Periarticular Multimodal Technique With (B) Continuous Femoral Nerve Block + Posterior Capsular Injection

The recovery from knee replacement surgery often involves a significant amount of pain. The best way to prevent/treat this pain is unknown. This study will compare two accepted methods of pain control in order to determine which is superior. The first method involves the injection of a solution containing multiple medications into the knee joint at the time of surgery. The second method involves the placement of a catheter adjacent to the femoral nerve which senses pain from the knee. This catheter is used to deliver local anesthetic which serves to block the transmission of pain signals from the nerve. The catheter will be left in place until 2 days after surgery. This method is combined with injection of local anesthetic in a particular area of the knee joint at the time of surgery. Patients will be followed until 2 days after surgery in order to determine which method is superior. We believe the second method will be deemed superior.

Randomized controlled study, Total knee arthroplasty, Post operative pain, Continuous Femoral Nerve Block, Posterior Capsular injection, Periarticular injection

A 20 ml bolus of saline will be given through the sham femoral nerve block catheter. Periarticular infiltration solution containing 400 mg Ropivicaine, 30 mg Ketorolac, 5 mg Epidural Grade Morphine, and 0.6 ml of 1:1000 Epinephrine will be made up to a volume of 100 ml with saline. Intra-op, 20 ml will be injected into the posterior capsule; 40 ml in the quadriceps mechanism, retinacular tissues, medial and lateral collateral ligaments; 40 ml in the skin and subcutaneous tissues. The sham catheter will be connected to a saline infusion running at 15 ml/hr until the morning of post-operative day 2.

A 20 ml bolus of 0.2% Ropivacaine will be given via a femoral nerve catheter. Periarticular infiltration will be performed intra-op. 20 ml of 1% Ropivacaine in the posterior capsule; 20 ml of normal saline in the quadriceps mechanism, retinacular tissues, medial and lateral collateral ligaments; 20 ml of normal saline for the skin and subcutaneous tissues. Postoperatively, the femoral catheter will be infused with 0.15% Ropivacaine running at 15 ml/hour until the morning of post-operative day 2

Number of patients with pain scores in the mild (numerical rating scale 0-3), moderate (NRS 3-7) and severe (NRS 7-10) range

Incidence of narcotic related side effects (nausea, vomiting, pruritis, euphoria, dysphoria, hallucination, respiratory depression)

Inclusion Criteria: ASA I, II, & III patients Elective primary total knee arthroplasty Spinal Anesthesia Exclusion Criteria: Patients refusing consent Contraindications to regional anesthesia Pre-existing neurological disease Allergy/contraindication to drugs used in the study Revision knee arthroplasty Patients with chronic pain/on narcotics preoperatively Pre-existing Rheumatoid Arthritis/Ankylosing Spondylitis Alcohol or drug abuse Psychiatric disorders Inability to use the outcome assessment tools Wheel chair or walker dependent for mobilization

Aragola S, Arenson B, Tenenbein M, Bohm E, Jacobsohn E, Turgeon T. Prospective randomized trial of continuous femoral nerve block with posterior capsular injection versus periarticular injection for analgesia in primary total knee arthroplasty. Can J Surg. 2021 Apr 28;64(3):E265-E272. doi: 10.1503/cjs.020519.