Femoral Versus Adductor Canal Continuous Peripheral Nerve Blocks for Knee Arthroplasty
Condition: Postoperative Pain Following Knee Arthroplasty
MeSH terms: Pain, Postoperative
Intervention: Control: Femoral perineural local anesthetic infusion; Experimental: Adductor Canal perineural local anesthetic infusion
Intervention description: The control group will receive a femoral nerve block and postoperative ropivacaine 0.2% infusion; The control group will receive an adductor canal nerve block and postoperative ropivacaine 0.2% infusion
Intervention MeSH terms: Anesthetics; Anesthetics, Local
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Enrollment: 80.0
Sex: All
Minimum age: 18 Years
Healthy volunteers: No

Summary:

      Patients typically experience moderate-to-severe pain following knee arthroplasty that is
      usually treated with a combination of oral and intravenous analgesics and enhanced by
      continuous peripheral nerve blocks. There are currently two locations to place a perineural
      catheter to provide analgesia following knee arthroplasty: a femoral nerve catheter and an
      adductor canal catheter. Both have been demonstrated to be effective following knee
      arthroplasty. However, it remains unknown if one location is superior to the other; or, more
      accurately, what the relative benefits are to each technique.

      While femoral CPNB has many benefits, one of the challenges of using this technique is that
      there is a decrease in quadriceps muscle strength which can be a limiting factor for
      rehabilitation. In contrast, the adductor canal catheter affects only the vastus medialis.
      This block may lessen block-induced quadriceps weakness following knee arthroplasty compared
      with a femoral infusion.

      The investigators hypothesize that compared with femoral perineural local anesthetic
      infusion, an adductor canal infusion is associated with a shorter time until four discharge
      criteria are met: (1) adequate analgesia; (2) independence from intravenous analgesics; (3)
      ability to ambulate 30 m; and (4) ability to stand, walk 3 m, and return to a sitting
      position without another's assistance.
    

Eligibility criteria:

        Inclusion Criteria:

          1. primary, unilateral knee arthroplasty

          2. age ≥ 18 years

          3. postoperative analgesic plan includes perineural local anesthetic infusion of 48-72
             hours

        Exclusion Criteria:

          1. morbid obesity as defined by a body mass index >40 (BMI=weight in kg/ [height in
             meters]

          2. chronic, high-dose opioid use (greater than 20mg oxycodone-equivalent opioid use daily
             within the 2 weeks prior to surgery and duration of use >4 weeks)

          3. history of opioid abuse

          4. allergy to study medications

          5. known renal insufficiency (creatinine > 1.5 mg/dL)

          6. pregnancy

          7. incarceration

          8. any known neuro-muscular deficit of the ipsilateral femoral nerve, obturator nerve
             and/or quadriceps muscle (including diabetic peripheral neuropathy); and inability to
             ambulate 30 m preoperatively.