Ultrasound-guided Selective Blockade of the Saphenous and Obturator Nerves Following Total Knee Arthroplasty

Study Overview
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Brief Summary
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The investigators aimed to evaluate the efficacy of selective low volume ultrasound-guided blockades of the saphenous and obturator nerves on dynamic and rest pain 24-hours post-operatively for patients undergoing unilateral primary total knee arthroplasty.

Detailed Description
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A femoral nerve block is the recommended strategy in many surgical centers to supplement multimodal analgesic regime following total knee arthroplasty (TKA) (i.e. both for spinal and general anesthesia). However, a femoral nerve block will often result in quadriceps paralysis, and this will increase the risk for the patient to fall as long as the femoral block have effect. Thus, the search for sensory nerve blocks to stop pain after TKA is a very interesting topic. The saphenous nerve is a purely sensory nerve, and the posterior branch of the obturator nerve is a mixed nerve, where the motor component only affects part of the adductor major muscle.

Official Title
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Selective Blocks for Total Knee Arthroplasty

Conditions
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Knee Arthroplasty, Total

Intervention / Treatment
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* Drug: nerve block with ropivacaine
* Drug: nerve block with ropivacaine and with saline
* Drug: nerve block with saline


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: American Society of Anesthesiologists' physical classification I-III Age ≥ 18 years undergoing primary unilateral total knee arthroplasty Exclusion Criteria: Inability to cooperate Inability to speak and understand Danish Allergy to any drugs used in the study Drug or alcohol abuse Pregnancy or nursing Opioid abusers

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: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: Saphenous and obturator nerve block<br>5 ml of ropivacaine 0.75% for the saphenous nerve and 10 ml of ropivacaine 0,75% for the obturator nerve block. Ropivacaine 0.75% for nerve blockades for both nerves mentioned. | Drug: nerve block with ropivacaine<br>* Ultrasound guided nerve blocks of the saphenous and obturator nerve, posterior branch with ropivacaine 0.75% for both nerve branches<br>* Other names: Saphenous and obturator nerve block with ropivacaine;|
| Active Comparator: Saphenous nerve block<br>5 ml of ropivacaine 0.75% for the saphenous nerve and 10 ml of isotonic saline for the obturator nerve block. Ropivacaine 0.75% for the saphenous nerve block and saline for the obturator nerve block | Drug: nerve block with ropivacaine and with saline<br>* nerve blocks of the saphenous nerve with ropivacaine 0.75% and obturator nerve, posterior branch with saline<br>* Other names: Saph block with ropivacaine and obtur block with saline;|
| Placebo Comparator: Placebo nerve block<br>5 ml of isotonic saline for the saphenous nerve and 10 ml of isotonic saline for the obturator nerve block. Saline for nerve blockades for both nerves mentioned. | Drug: nerve block with saline<br>* Ultrasound guided nerve blocks of the saphenous and obturator nerve, posterior branch with saline for both nerve branches<br>* Other names: saphenous and obturator nerve block with saline;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Dynamic pain (pain upon movement) quantified as area-under-the-curve (AUC) 24-hours post-operatively | NRS 0-10 | 24 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain at rest quantified as area-under-the-curve (AUC) 24-hours post-operatively | NRS 0-10 | 24 hours | 
| Total opioid consumption | mg | 24 hours | 
| Nausea and vomiting | NRS 0-10 | 24 hours | 
| Time to first mobilization | hours | 24 hours | 
| Length of stay in recovery and hospital | hours | 72 hours | 
| Number of clinical complications | total number | 72 hours |