Dexmedetomidine as Adjuvant for FNB in TKA

Study Overview
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Brief Summary
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The aim of the study was to find out whether addition of dexmedetomidine to lower concentration of ropivacaine preoperatively in femoral nerve block (FNB) would intensify analgesia and preserve quadriceps muscle strength after TKA.

Detailed Description
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We designed this study to evaluate whether dexmedetomidine added to lower concentration of ropivacaine for FNB can intensify analgesic effect and meanwhile reduce the possibility of lower limb (or quadriceps) weakness. Three groups were compared: 0.2% ropivacaine (H group), 0.1% ropivacaine (L group) and ropivacaine 0.1% added with 2 μg/kg dexmedetomidine (LD group).

Official Title
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Comparison of Dexmedetomidine as Adjuvant to Different Concentrations of Ropivacaine for Femoral Nerve Blockade in Patients Undergoing Total Knee Arthroplasty

Conditions
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Nerve Block, Dexmedetomidine

Intervention / Treatment
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* Drug: Dexmedetomidine
* Procedure: ultrasound-guided femoral nerve block
* Device: intravenous patient-controlled analgesia pump with morphine
* Procedure: Continuous femoral nerve block


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: ASA I-II scheduled for total knee arthroplasty Exclusion Criteria: refusal to participate in this study unicompartmental knee arthroplasty BMI > 35 kg/m2 congnitive or phychiatric history refusal of general anesthesia contraindication to laryngeal mask airway insertion contraindication to peripheral nerve block (localized infections, sepsis, coagulopathy, bleeding diathesis or preexisting lower extremity neurological abnormality) allergy to the drugs used

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: H group<br>H group stands for High concentration group. A single bolous of 20 ml ropivacaine 0.2% in ultrasound-guided femoral nerve block (FNB) before the TKA surgery, followed by continuous femoral nerve block (CFNB) using ropivacaine 0.2% (5 ml/h) for postoperative analgesia which started right after surgery. After surgery, all patients received multimodal analgesia of 200mg celecoxib every 12 hours. All subjects received anothother intravenous patient-controlled analgesia pump (IV-PCA pump), which included 50 mg morphine in 50 ml saline: bolus 2 mg; lock out time, 15 minutes. | Procedure: ultrasound-guided femoral nerve block<br>* ultrasound-guided femoral nerve block, a single bolous of 20 ml ropivacaine (concentration 0.2% for H group or 0.1% for L group) before surgery followed by continuous femoral nerve block using an infusion rate of ropivacaine 0.2% 5 ml/h for postoperative analgesia started right after surgery<br>* Other names: FNB;Device: intravenous patient-controlled analgesia pump with morphine<br>* All subjects received intravenous patient-controlled analgesia (IV-PCA) pumps to measure additional morphine consumption, which included 50 mg morphine in 50 ml saline: bolus 2 mg; lock out time, 15 minutes.<br>* Other names: IV-PCA pump;Procedure: Continuous femoral nerve block<br>* All the continuous femoral nerve block infusion regimes in the pump were connected to CFNB catheter, which contained only ropivacaine with different concentrations (ropivacaine 0.1% for L group and LD group; ropivacaine 0.2% for H group, 5 ml/h).<br>* Other names: CFNB;|
| Experimental: L group<br>L group stands for low concentration group. A single bolous of 20 ml ropivacaine 0.1% in ultrasound-guided femoral nerve block (FNB) before the TKA surgery, followed by continuous femoral nerve block (CFNB) using ropivacaine 0.1% (5 ml/h) for postoperative analgesia which started right after surgery. All subjects received anothother intravenous patient-controlled analgesia pump (IV-PCA pump), which included 50 mg morphine in 50 ml saline: bolus 2 mg; lock out time, 15 minutes. | Procedure: ultrasound-guided femoral nerve block<br>* ultrasound-guided femoral nerve block, a single bolous of 20 ml ropivacaine (concentration 0.2% for H group or 0.1% for L group) before surgery followed by continuous femoral nerve block using an infusion rate of ropivacaine 0.2% 5 ml/h for postoperative analgesia started right after surgery<br>* Other names: FNB;Device: intravenous patient-controlled analgesia pump with morphine<br>* All subjects received intravenous patient-controlled analgesia (IV-PCA) pumps to measure additional morphine consumption, which included 50 mg morphine in 50 ml saline: bolus 2 mg; lock out time, 15 minutes.<br>* Other names: IV-PCA pump;Procedure: Continuous femoral nerve block<br>* All the continuous femoral nerve block infusion regimes in the pump were connected to CFNB catheter, which contained only ropivacaine with different concentrations (ropivacaine 0.1% for L group and LD group; ropivacaine 0.2% for H group, 5 ml/h).<br>* Other names: CFNB;|
| Experimental: LD group<br>LD group stands for low concentration group with dexmedetomidine. A single bolous of 20 ml ropivacaine 0.1% plus 2 μg/kg dexmedetomidine in ultrasound-guided femoral nerve block (FNB) before the TKA surgery, followed by continuous femoral nerve block (CFNB) using ropivacaine 0.1% (5 ml/h) for postoperative analgesia which started right after surgery. All subjects received anothother intravenous patient-controlled analgesia pump (IV-PCA pump), which included 50 mg morphine in 50 ml saline: bolus 2 mg; lock out time, 15 minutes. | Drug: Dexmedetomidine<br>* Dexmedetomidine added to lower concentration of ropivacaine for postoperative analgesia in FNB<br>Procedure: ultrasound-guided femoral nerve block<br>* ultrasound-guided femoral nerve block, a single bolous of 20 ml ropivacaine (concentration 0.2% for H group or 0.1% for L group) before surgery followed by continuous femoral nerve block using an infusion rate of ropivacaine 0.2% 5 ml/h for postoperative analgesia started right after surgery<br>* Other names: FNB;Device: intravenous patient-controlled analgesia pump with morphine<br>* All subjects received intravenous patient-controlled analgesia (IV-PCA) pumps to measure additional morphine consumption, which included 50 mg morphine in 50 ml saline: bolus 2 mg; lock out time, 15 minutes.<br>* Other names: IV-PCA pump;Procedure: Continuous femoral nerve block<br>* All the continuous femoral nerve block infusion regimes in the pump were connected to CFNB catheter, which contained only ropivacaine with different concentrations (ropivacaine 0.1% for L group and LD group; ropivacaine 0.2% for H group, 5 ml/h).<br>* Other names: CFNB;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change of manual muscle testing (MMT) over 72 hours postoperatively | The MMT grading was recorded from 0 to 5 to measure muscle strength at 6, 12, 24, 36, 48 and 72 hours after surgery. | 0-72 hours postoperatively | 
| Change of Timed Up and Go test (TUG) over 72 hours postoperatively | TUG test was used to assess the patient's mobility that requires both balance and static. It was measured at 24, 48 and 72 hours after surgery. | 0-72 hours postoperatively | 
| Change of numeric rating scales (NRS) over 72 hours postoperatively | NRS was used to evaluate postoperative pain control. They were measured at 6, 12, 24, 36, 48 and 72 hours after surgery. | 0-72 hours postoperatively | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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femoral nerve blockade, dexmedetomidine, ropivacaine, anesthesia