Dexmedetomidine as an Adjuvant for Femoral Nerve Block and Functional Recovery After Total Knee Arthroplasty

Study Overview
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Brief Summary
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Femoral nerve block (FNB) is a first-line analgesic technique for multimodal analgesia after total knee arthroplasty (TKA). Recent studies and meta-analysis indicate that dexmedetomidine combined with local anesthetics for FNB can prolong the analgesic duration, improve the analgesic efficacy, inhibit local inflammatory response, and reduce narcotic consumption. The investigators hypothesize that dexmedetomidine combined with ropivacaine for FNB can also improve functional recovery in aged patients after TKA.

Detailed Description
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Many patients following total knee arthroplasty (TKA) complain moderate to severe postoperative pain. Multimodal analgesia, a combination of different techniques and analgesic agents, plays an increasingly important role to relieve pain after TKA. Femoral nerve block (FNB) is a first-line analgesic technique for multimodal analgesia after TKA. But local anesthetics alone often exert limited potency of analgesia and are insufficient to avoid supplemental opioid usage. Dexmedetomidine, a selective alpha 2-adrenergic receptor agonist, is widely used in clinical settings due to its properties of sedation, anxiolysis, analgesia, and sleep promotion. Recent studies and meta-analysis indicate that dexmedetomidine combined with local anesthetics for FNB can prolong the analgesic duration, improve the analgesic efficacy, inhibit local inflammatory response, and reduce narcotic consumption. The investigators hypothesize that dexmedetomidine combined with ropivacaine for FNB can also improve the functional recovery in aged patients after TKA.

Official Title
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Impacts of Dexmedetomidine as an Adjuvant for Femoral Nerve Block on Functional Recovery in Aged Patients After Total Knee Arthroplasty: a Randomized, Double-blinded, Controlled Trial

Conditions
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Elderly, Total Knee Arthroplasty, Femoral Nerve Block, Dexmedetomidine, Functional Outcome

Intervention / Treatment
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* Drug: Dexmedetomidine
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age ≥65 years but <90 years; Scheduled to undergo unilateral total knee arthroplasty; Planned to use femoral nerve block and patient-controlled intravenous analgesia (PCIA) for multimodal analgesia. Exclusion Criteria: Scheduled for bilateral total knee arthroplasty or revision surgery; Contraindications to femoral nerve block; Preoperative history of schizophrenia, myasthenia gravis, inability to communicate because of coma, severe dementia, or language barriers; Preoperative history of hemorrhagic disease or coagulopathy; Preoperative obstructive sleep apnea (diagnosed sleep apnea syndrome or a STOP-Bang score ≥3 combined with a serum bicarbonate ≥28 mmol/L); Sick sinus syndrome, severe sinus bradycardia (< 50 beats per minute), or second-degree or above atrioventricular block without pacemaker; Severe hepatic dysfunction (Child-Pugh class C), severe renal dysfunction (requirement of renal replacement therapy before surgery), or American Society of Anesthesiologists physical status >III; Preexistent delirium (diagnosed by Three-Dimensional Confusion Assessment Method); Under treatment with dexmedetomidine or clonidine.

Ages Eligible for Study
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Minimum Age: 65 Years
Maximum Age: 89 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: Prevention
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Dexmedetomidine group<br>Patients in the dexmedetomidine group receive single-shot femoral nerve block preoperatively using a mixture of 0.375% ropivacaine and 1.0 μg/kg dexmedetomidine, in a total volume of 20 ml. Postoperatively, patient-controlled intravenous analgesia is provided for at least 48 hours. The formula is sufentanil (1.25 μg/ml), diluted with normal saline to 100 ml. 5-HT3 receptor antagonist is added when necessary. The pump is programmed to deliver 2-ml boluses at 6 to 8-minute lockout intervals with a background infusion rate at 1 ml/h. | Drug: Dexmedetomidine<br>* Patients in the dexmedetomidine group receive single-shot femoral nerve block preoperatively using a mixture of 0.375% ropivacaine and 1.0 μg/kg dexmedetomidine, in a total volume of 20 ml.<br>* Other names: Dexmedetomidine hydrochloride;|
| Placebo Comparator: Control group<br>Patients in the control group receive single-shot femoral nerve block preoperatively using a mixture of 0.375% ropivacaine and normal saline, in a total volume of 20 ml. Postoperatively, patient-controlled intravenous analgesia is provided for at least 48 hours. The formula is sufentanil (1.25 μg/ml), diluted with normal saline to 100 ml. 5-HT3 receptor antagonist is added when necessary. The pump is programmed to deliver 2-ml boluses at 6 to 8-minute lockout intervals with a background infusion rate at 1 ml/h. | Drug: Placebo<br>* Patients in the control group receive single-shot femoral nerve block preoperatively using a mixture of 0.375% ropivacaine and normal saline, in a total volume of 20 ml.<br>* Other names: Normal saline;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Quality of life at 3 months after surgery-mental component summary score | Quality of life is assessed with 12-item short-form (SF-12, it is summarized into physical and mental component summary scores, each ranges from 0 to 100, with higher scores indicating better quality of life). | At 3 months after surgery | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Incidence of delirium within the first 3 days after surgery | Delirium is assessed with the Three-dimensional Confusion Assessment Method (3D CAM) twice daily (8:00-10:00 and 18:00-20:00) over the first 3 postoperative hospital days. Patients with endotracheal intubation will be assessed with the Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) twice daily during the same period. | The first 3 days after surgery | 
| Length of stay in hospital after surgery | Length of stay in hospital after surgery | Up to 30 days after surgery | 
| Incidence of non-delirium complications (including all-cause mortality) within 30 days after surgery | Incidence of non-delirium complications (including all-cause mortality) within 30 days after surgery | Up to 30 days after surgery | 
| Quality of life at 3 months after surgery-physical component summary score | Quality of life is assessed with 12-item short-form (SF-12, it is summarized into physical and mental component summary scores, each ranges from 0 to 100, with higher scores indicating better quality of life). | At 3 months after surgery | 
| The overall subjective sleep quality at 3 months after surgery | Evaluated by the Pittsburgh Sleep Quality Index, which estimates overall subjective sleep quality in the past 30 days. Overall score ranges from 0 to 21. A higher score indicates worse sleep quality, and a score greater than 5 indicates poor sleep quality. | At 3 months after surgery | 
| The severity of arthritic symptoms at 3 months after surgery | Assessed with WOMAC osteoarthritis index (score ranges from 0 to 96, with higher score indicating more severe symptoms). | At 3 months after surgery | 
| Cognitive function at 3 months after surgery | Evaluated with the modified Telephone Interview for Cognitive Status (TICS-m), a 12-item questionnaire that provides an assessment of global cognitive function by verbal communication via telephone. The score ranges from 0 to 48, with higher score indicating better function. | At 3 months after surgery | 
| Event-free survival at 3 months after surgery | Time from surgery to new-onset diseases or all-cause death, whichever comes first. New-onset disease indicates those that required hospital admission and/or interventional procedure. | At 3 months after surgery | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Elderly, Total knee arthroplasty, Femoral nerve block, Dexmedetomidine, Functional outcome