Adductor Canal Block With Continuous Infusion Versus Intermittent Boluses and Morphine Consumption

Study Overview
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Brief Summary
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The investigators believe sufficient spread to all nerves within the adductor canal-and thereby sufficient analgesia-can only be obtained by bolus injections and not by continuous infusions via a catheter. The aim of the study is to investigate whether an adductor canal block performed as repeated intermittent boluses provides superior pain relief to continuous infusion. The investigators hypothesize that adductor canal block performed as intermittent boluses via a catheter will reduce morphine consumption and pain as well as enhance ambulation and muscle strength compared with continuous infusion.

Official Title
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Adductor Canal Block With Continuous Infusion Versus Intermittent Boluses and Morphine Consumption: A Randomized, Triple-masked, Controlled Study

Conditions
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Postoperative Pain

Intervention / Treatment
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* Drug: ropivacaine 0.2%


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients scheduled for total knee arthroplasty in spinal anesthesia Patients who gave their written informed consent to participating in the study after having fully understood the contents of the protocol and restrictions American society of anesthesiologists 1-3 Ability to perform a timed up and go test preoperatively Exclusion Criteria: Patients who cannot cooperate Patients who cannot understand or speak Danish. Patients with allergy to the medicines used in the study Patients with a daily intake of strong opioids (morphine, oxycodone, ketobemidone, methadone, fentanyl) during the last 4 weeks Patients suffering from alcohol and/or drug abuse - based on the investigator's assessment Rheumatoid arthritis BMI > 40 Neuromuscular pathology in the lower limbs Pregnancy

Ages Eligible for Study
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Minimum Age: 18 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: Intermittent bolus<br>ropivacaine 0.2%, 21 ml every 3 hours | Drug: ropivacaine 0.2%<br>* Adductor canal block. Placed immediately postoperative. Intervention stops on POD2 12PM<br>|
| Active Comparator: Continuous infusion<br>ropivacaine 0.2%, 7ml/h | Drug: ropivacaine 0.2%<br>* Adductor canal block. Placed immediately postoperative. Intervention stops on POD2 12PM<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Total opioid consumption | Difference in total opioid consumption (patient controlled analgesia pump and any potential rescue administration) between groups, from end of surgery until 12 pm on postoperative day (POD) 2. | 2 days postoperative | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pains scores during knee flexion as assessed by the Visual analogue scale (VAS) | Visual analogue scale (VAS) pain scores (0-100 mm) during 45 degrees active knee flexion analyzed using a linear mixed model with the inclusion of all time points (Day of surgery (DOS): 8 pm, POD 1: 8 am, 12 pm, 8 pm, POD 2: 8 am and 12 pm). | 2 days postoepratively | 
| Pain at rest as assessed by the VAS pain scores | VAS pain scores (0-100 mm) at rest analyzed using a linear mixed model with the inclusion of all time points (DOS: 8 pm, POD 1: 8 am, 12 pm, 8 pm, POD 2: 8 am and 12 pm). | 2 days postoperatively | 
| Pain during the Timed Up and Go test as assessed by the VAS | Worst pain (VAS, 0-100 mm) during the Timed Up and Go test at 12 pm on POD 1 and 2. | 1 and 2 days postoperatively | 
| Quadriceps strength assessed as maximum voluntary isometric contraction in percentage of preoperative baseline values at 12 pm on POD 1 and 2 | Quadriceps strength assessed as maximum voluntary isometric contraction in percentage of preoperative baseline values at 12 pm on POD 1 and 2. | 1 and 2 days postoperatively | 
| Timed Up and Go test | Time (seconds) to perform the Timed Up and Go test at 12 pm on POD 1 and 2. | 1 and 2 days postoperatively | 
| Number of patients able to perform the Timed Up and Go test | Number of patients able to perform the Timed Up and Go test at 12 pm on POD 1 and 2. | 1 and 2 days postoperatively | 
| 6 min walk test | Distance ambulated (m) during the 6 min walk test performed at 12 pm on POD 1 and 2. | 1 and 2 days postoperativley |