Single Injection Adductor Canal Block vs Catheter for Total Knee Arthroplasty
Condition: Total Knee Arthroplasty
Study type: Interventional
Phase: Phase 4

Summary: 
      This study investigates single injection adductor canal block (ACB) with or without
      intravenous dexamethasone and adductor canal catheter for pain management of total knee
      arthroplasty. This is a non-inferiority trial seeking to determine whether single injection
      ACB with dexamethasone is "no worse" than a continuous catheter.
    

Detailed description: 
      1. Purpose

           To determine whether single shot adductor canal nerve blocks with intravenous
           dexamethasone are non-inferior to continuous adductor canal blockade.

        2. Hypotheses

           The use of adductor canal nerve block with intravenous dexamethasone will not be
           inferior to continuous adductor canal blockade for opioid requirements 24h post
           operatively.

           The single injection adductor canal block without dexamethasone will have the most
           opioid consumption. The dexamethasone and catheter groups will be superior to single
           injection alone in terms of 12 and 48h opioid consumption, length of stay, anti-emetic
           usage, pain score and quality of recovery score.

        3. Justification

           Total knee arthroplasty is a very commonly performed operation in North America, with a
           high propensity for postoperative pain. Inadequate analgesia limits functional recovery
           and leads to delays in hospital discharge, as a result of poor mobility. Effective
           analgesia allows for earlier mobilization and improved postoperative recovery, with a
           multi-modal regime being the ideal method to achieve this.

           Currently a multi-modal regime is provided to patients: intraoperatively with a
           neuraxial technique (spinal anesthesia), along with surgeon infiltrated local anesthetic
           at the end of the operation, and then postoperatively using systemic opioids via patient
           controlled analgesia (PCA). Opioids have many side effects, including nausea and
           vomiting, sedation, respiratory depression and urinary retention. These all lead to
           delay in ambulation and recovery.

           Many centers now incorporate peripheral nerve blocks as part of the multi-modal
           analgesic regime, with continuous femoral nerve blockade being commonly used for
           analgesia. This does decrease the amount of postoperative opioid used, but has the
           downside of causing quadriceps muscle weakness leading to an increased risk of falls and
           delayed ambulation. For this reason, there has been an increase in the use of the
           adductor canal block, a nerve block of the distal femoral nerve at the mid-thigh level,
           that has been shown to preserve quadriceps function better than a femoral nerve block,
           whilst still ensuring decreased opioid use. To date, no studies have compared single
           shot adductor canal block with continuous adductor canal blockade, but both have been
           shown to be comparable to femoral nerve blockade, whilst decreasing the likelihood of
           quadriceps muscle weakness.

           Further to this, it has been shown that the addition of dexamethasone, administered via
           the intravenous or perineural route to peripheral nerve blockade, prolongs the duration
           of analgesia. Perineural administration of dexamethasone is an off label use and there
           is also a theoretical risk of neurotoxicity from dexamethasone itself. Findings to date
           indicate that the efficacy of dexamethasone administered intravenously is non-inferior
           to perineural injection. Both routes prolong the analgesic benefit of peripheral nerve
           blocks with similar reductions in opioid requirements.

           Opioid PCA is the most commonly used modality for postoperative analgesia following
           total knee arthroplasty. The information from this study will enable ascertainment of
           the best method for allowing patients good functional recovery, whilst minimizing opioid
           side effects.

        4. Objectives

           The primary aim of this study is to compare the efficacy of adductor canal nerve block,
           with and without intravenous dexamethasone, and continuous adductor canal blockade with
           a catheter to ascertain cumulative opioid consumption post-operatively. Specifically,
           the trial seeks to answer whether the adductor canal block with dexamethasone fares no
           worse (non-inferior) than a continuous catheter.

           The secondary aims are to compare the quality of anesthesia recovery using the QoR-40
           questionnaire administered at 48 hours postoperatively, pain score, length of hospital
           stay, complications of nerve blockade, incidence of catheter dislodgement and opioid
           side effects (nausea/vomiting) with the different techniques.

        5. Research Methods

           Trial Design

           This will be a randomize controlled, non-blinded, non-inferiority trial, involving
           patients having primary unilateral total knee arthroplasty. There are three arms:
           adductor canal single injection (baseline control), adductor canal single injection plus
           dexamethasone (test intervention) and adductor canal catheter (active control).

           Setting

           This will be a single-centre trial at UBC Hospital (UBCH).

           B. Randomization

           Prior to surgery, for each consented patient, a sealed unmarked opaque envelope will be
           opened to determine the modality of analgesia that the patient will receive. The
           patients will either receive an adductor canal block postoperatively, an adductor canal
           block postoperatively along with intravenous dexamethasone, or have an adductor canal
           catheter placed postoperatively for continuous adductor canal blockade.

           D. Data Collection

           Demographic data including patient age, sex, height, weight, BMI, and medications
           including analgesics, comorbidities and American Society of Anesthesia (ASA)
           classification will be determined from the anesthetic record.

           Numerical Rating Scale (NRS) pain scores from 0-10 as well as cumulative opioid
           consumption in oral morphine equivalents will be determined at set time points of 12,
           24, 48 hours. The data will be determined from the patient's pain flow sheet and
           medication administration record (MAR), which are part of the standard charting found on
           the hospital ward. Opioid data from PCA will be obtained from the hospital database
           which electronically logs usage. The patient's chart will also be used to note
           anti-emetic medication usage. At 48 hours, all participants will be provided with a
           QoR-40 questionnaire, a validated 40 item questionnaire on the quality of recovery from
           anesthesia. The time of discharge will be recorded from the hospital data base.

           Complications from adductor canal catheters will be recorded, such as catheter
           dislodgement and site infection. For patients unable to complete the study, the reason
           will be noted and data will be included in an intention to treat analysis.

           E. Statistical Analysis

           Sample Size:

           The investigators do not have institutional data of standard deviation (SD) of morphine
           equivalent consumption for primary total knee arthroplasty. Based on previous studies,
           the standard deviation of morphine equivalent consumption at 24h is estimated to be 20
           mg IV. We consider a reduction of 10 mg to be clinically relevant at this time point and
           therefore set it as the non-inferiority margin. Using the following online calculator:
           https://www.sealedenvelope.com/power/continuous-noninferior/ based on a power of 80% and
           significance level of 5%, the number of patients required per group is 50. The aim is to
           recruit 60 patients per group to account for potential drop outs.

        6. Data Analysis: Categorical data will be analysed with chi-squared tests. Numeric
           variables will be compared with independent T-tests if distributions were normal. If
           Kolmogorov-Smirnoff test for normality of distribution was significant non-parametric
           Mann Whitney U tests will be utilized. Statistical significance will be assumed if P
           <0.05.
    

Intervention name(s): Adductor canal block; Adductor canal block with dexamethasone; Adductor canal catheter; Bupivacaine; Fentanyl; Ropivacaine 0.5% Injectable Solution; Dexamethasone
Intervention type(s): Drug; Drug; Drug; Drug; Drug; Drug; Drug
Intervention description(s): Spinal anesthesia with 2-3 ml 0.5% bupivacaine and 0-20mcg of fentanyl. At the end of the case, the surgeon will infiltrate 30ml 0.5% ropivacaine peri-articularly. 20ml 0.5% ropivacaine in the adductor canal in PACU.; Spinal anesthesia with 2-3 ml 0.5% bupivacaine and 0-20mcg of fentanyl. At the end of the case, the surgeon will infiltrate 30ml 0.5% ropivacaine peri-articularly. 20ml 0.5% ropivacaine in the adductor canal along with 8mg dexamethasone IV in PACU.; Spinal anesthesia with 2-3 ml 0.5% bupivacaine and 0-20mcg of fentanyl. At the end of the case, the surgeon will infiltrate 30ml 0.5% ropivacaine peri-articularly. 20ml 0.5% ropivacaine and a catheter placed in PACU, with a continuous infusion of 0.2% ropivacaine started.; Used in spinal anesthetic; May or may not be used in spinal anesthetic; Local anesthetic to be used by surgeon as local infiltration and by anesthesiologist in adductor canal block.; To be given intravenously at time of nerve block to one of the study arms.
Intervention MeSH terms: Dexamethasone; Dexamethasone acetate; Fentanyl; Bupivacaine; Ropivacaine; BB 1101
Allocation: Randomized
Intervention model: Parallel Assignment
Masking: None (Open Label)
Primary purpose: Treatment