Comparing Femoral Nerve Catheters to Single Shot Femoral Nerve Blocks for Total Knee Replacement Surgery
Condition: Knee Osteoarthritis
MeSH terms: Osteoarthritis; Osteoarthritis, Knee
Study type: Interventional

Summary: 
      The purpose of this study is to compare two methods of pain control used during total knee
      joint replacement surgery. The pain medication that will be used for this study is not
      experimental.

      The investigators will compare the single shot femoral nerve block (SSFNB) and Femoral Nerve
      Block (FNB) plus continuous femoral nerve catheter (CFNC) to determine which method gives
      patients better pain control, increasing the capability to participate in physical therapy
      and decreasing the consumption of other pain medication. With either the single shot or the
      catheter the local numbing medication called ropivacaine will be used.
    

Detailed description: 
      The study will be a randomized controlled blinded study with a sham control arm. The patients
      will be randomized to either a single shot FNB with placement of a catheter on the skin (sham
      control) or a conventional CFNC with catheter.

      The group with SSFNB will receive a femoral nerve block before the surgery in the
      pre-operative area guided by a nerve stimulator and ultrasound. A bolus of 0.5 % ropivacaine
      will be injected around the femoral nerve. A catheter would be placed on the skin, without
      penetration, with occlusive dressing applied over the site. A standard size saline bag will
      be placed on the pump but will not be turned on. The tubing will be opaque and a bag will be
      placed over the pump to blind the patient to the medication, or lack of medication, being
      administered. The patient, nursing staff and physical therapists will be blinded to the
      presence of a sham catheter. The infusion will be labelled 'Study Drug R' or 'Study Drug N'
      in the electronic medicine prescription.

      The group randomized with active drug by CFNB would have a continuous femoral catheter placed
      using nerve stimulator and ultrasound. Catheter will be bolused with 0.5 % ropivacaine around
      the femoral nerve and occlusive dressing applied over the catheter.

      After placement of the femoral nerve block patients will be transported to the operating room
      and spinal anesthesia with bupivacaine and fentanyl will be performed. Intra-operative
      sedation of propofol infusion will be titrated to the discretion of the anaesthesia team.
      Patients will receive scheduled as well as rescue analgesia as per clinical pathway protocol.

      Patients with CFNB will receive ropivacaine 0.2% infusion (the infusion rate will be
      dependent on the clinical judgement of the anaesthesiologist) in the post anaesthesia care
      unit (PACU) after the spinal anaesthesia has worn off. The infusion will be continued for the
      duration of the catheter, 4am POD one. Patients with SSFNB will not receive any infusion
      through the sham catheter.

      The catheters will be removed on post-operative day (POD) one at about 8 am. Patient's pain
      score using visual analogue score (VAS) will be assessed. Functional status will be assessed
      by the physical therapist on POD one. The therapist will assess and document the distance
      walked, assistive device used, level of assist needed to ambulate, and knee proprioception or
      continued recommendation of the knee immobilizer.

      Patients will be assessed in the PACU and POD 1 and 2. Recordings will be made of total
      opioid consumption in morphine equivalents, VAS score from 0-10 both at rest and on
      participation in physical therapy, incidence of nausea and vomiting and functional status
      during physical therapy.
    

Intervention name(s): Femoral Nerve Catheters; Single Shot Femoral Nerve Blocks
Intervention type(s): Drug; Drug
Intervention description(s): Catheter will be bolused with 0.5 % ropivacaine around the femoral nerve and occlusive dressing applied over the catheter.
Patients with CFNB will receive ropivacaine 0.2% infusion (the infusion rate will be dependent on the clinical judgement of the anaesthesiologist); The group with SSFNB will receive a femoral nerve block before the surgery in the pre-operative area guided by a nerve stimulator and ultrasound. A bolus of 0.5 % ropivacaine will be injected around the femoral nerve.
Other intervention name(s): 0.5% ropivacaine bolus followed by 0.2% infusion; 0.5% ropivacaine
Intervention MeSH terms: Ropivacaine
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Double (Participant, Outcomes Assessor)
Primary purpose: Treatment
Keywords: TKA; TKR; Knee OA; pain management; Femoral Nerve Catheter; Single Shot Femoral Nerve Blocks