Continuous Adductor Canal Blocks Vs. Low Dose Femoral Nerve Blocks For Early Rehabilitation After Total Knee Arthroplasty
Condition: Pain, Postoperative; Total Knee Arthroplasty (TKA)
MeSH terms: Pain, Postoperative
Intervention: Continuous Femoral Nerve Block; Nerve Block, Continuous Adductor Canal; Continuous Sciatic Nerve Block; Bupivacaine
Intervention description: A 27g plastic catheter placed below the inguinal crease to perform a conduction blockade of the sensory components of the femoral nerve in order to decrease pain in the knee after total knee arthroplasty; A 27g plastic catheter placed on the anterior medial thigh midway between the groin and knee to provide a local anesthetic conduction blockade of the sensory components of the femoral nerve in order to decrease pain in the knee after total knee arthroplasty; A transgluteal approach to the sciatic nerve is use to place a 27g catheter. It will only be dose postoperatively after verifying sciatic nerve function still intact. The infusion will be 0.003% bupivacaine at 2ml/hr. This is not the intervention of interest, but our institution's predominant practice is to include the sciatic nerve block as part of the analgesic regimen for total knee arthroplasty.; The concentration of the continuous infusion of bupivacaine though the peripheral nerve catheters will be 0.0625% for the femoral and adductor canal blocks and the concentration for the sciatic continuous catheter will be 0.03%.
Intervention MeSH terms: Bupivacaine
Phase: Phase 4
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: Single (Outcomes Assessor)
Enrollment: 62.0
Sex: All
Minimum age: 18 Years
Maximum age: 75 Years
Healthy volunteers: Accepts Healthy Volunteers
Keywords: Continuous Femoral Nerve Block; Continuous Adductor Canal Block

Summary:

      Recently, several articles have suggested or reported that Adductor Canal Blocks (ACBs) offer
      adequate or equal analgesia and may promote better performance in early rehabilitation
      following Total Knee Arthroplasty (TKA) when compared to the more commonly used Femoral Nerve
      Block (FNB). A common feature of these studies has been the use of moderate to high
      concentration local anesthetics (e.g. 0.2% or 0.5% Ropivacaine respectively) which when
      injected by a large motor nerve will inevitably cause weakness. However, the practice at our
      institution has long been a continuous femoral nerve block (CFNB) with a lower concentration
      local anesthetic (0.0625% Bupivacaine). Over the past several years the investigators have
      performed several thousand CFNBs using this technique which has offered the advantage of
      minimal motor weakness and adequate analgesia.

      The primary goal of this study is to determine if our established practice of using a low
      concentration continuous FNB inserted about 5cm caudal to the groin crease (the apex of the
      femoral triangle) using a low infusion rate of 2ml/hr is comparable to the emerging practice
      of inserting a Continuous Peripheral Nerve Block (CPNB) in the anatomic adductor canal (AC) -
      infusing at 4ml/hr. A secondary goal is to study the effect of cumulative volume of local
      anesthetic infused through a FNB when at a rate of 2ml/hr compared to a rate of 4ml/hr in the
      48-hour postoperative period.

      Definitions of the location of the adductor canal are debated heavily in literature, but they
      seem to agree that the middle 1/3 of the thigh contains the proximal AC while the distal 1/3
      of the thigh contains the adductor hiatus - the terminal end of the AC. Our study will
      require placement of the continuous ACB no more distal than 20cm cephalad to the superior
      pole of the patella due to placement prior to surgery and the need to keep the dressing out
      of the operative field. The CACB catheter will also not be placed any more proximal than 20cm
      distal to the ASIS. In addition to other exclusion criteria, these measurements will create
      an exclusion for patients with an iliac-to-patella distance less than 40cm. Iliac to Patella
      distance (IPD) will be measured at the pre-operative interview on the day of surgery with a
      measuring tape. External palpable landmarks of the Anterior superior iliac spine and the
      superior pole of the patella will be used.

      The primary outcome is based upon the ability to perform rehabilitation exercises
      postoperatively to the extent that criteria for discharge can be met. The primary outcome
      measured is the time at which a patient gains the ability to successfully perform a 75-feet
      unassisted walk. On the Day of Surgery (DOS), prior to any walking attempt, a secondary
      outcome measure will be to perform a 5-second sustained straight leg raise. Other secondary
      outcomes will be the number of days admitted prior to discharge, and average pain scores on
      DOS, Postoperative Day (POD) #1, and POD#2. The Day of discharge will also be used as a
      secondary outcome. Earlier discharge is becoming a goal of almost all healthcare systems to
      minimize costs.
    

Eligibility criteria:

        Inclusion Criteria:

          -  Able to consent to regional anesthesia and having primary total knee
             arthroplasty/replacement

        Exclusion Criteria:

          -  Body-Mass Index >40

          -  Iliac to Patella Distance (IPD) <40cm

          -  Pre-existing quadriceps weakness of involved surgical side Chronic opioid use (if
             using opioids within 4 weeks of surgery: excluded)