Ultrasound-guided Blocks for Ambulatory Knee Arthroscopy

Study Overview
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Brief Summary
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In this study, we wish to investigate the effect of ultrasound (US) -guided block of the saphenous nerve (SN) and the posterior branch of the obturator nerve (ONP) on postoperative pain and the use of opioids (morphine-like pain medicine) in the first 24 hours following ambulatory knee arthroscopy. We wish to investigate the analgesic effect of these two blocks compared to placebo (injection of local anesthetic with known pain blocking properties compared with injection of a saline solution), when used as a supplement to conventional oral analgesics. We hypothesize that patients receiving the active treatment may experience less pain during the first 24 hours after their operation than patients receiving the placebo treatment, and possibly require less opioid analgesics, experience less opioid related side effects and have a higher function level in this period than patients receiving the placebo treatment.

Official Title
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Ultrasound-guided Block of the Saphenous Nerve and Obturator Nerve, Posterior Branch, for Postoperative Pain Management After Ambulatory Knee Arthroscopy

Conditions
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Postoperative Pain, Postoperative Nausea and Vomiting, Postoperative Function Level

Intervention / Treatment
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* Procedure: Block of the SN and ONP
* Procedure: Placebo block
* Drug: Paracetamol
* Drug: Morphine
* Drug: Ondansetron
* Drug: Metoclopramide


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Planned ambulatory knee arthroscopy, except cruciate ligament surgery American Society of Anesthesiologists (ASA) class 1-3 Exclusion Criteria: Cannot cooperate Do not speak or understand Danish Daily use of opioid analgesics Allergy towards any of the drugs used in the investigation Medicine abuse (at the investigators discretion) Alcohol abuse, as defined by the National Board of Health General anesthesia contraindicated, or the patient wants spinal anesthesia Visualization of necessary structures by ultrasound not possible, or block not possible for other technical reasons

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: Block arm<br>Ultrasound guided block of the SN and ONP with 7.5 ml of Ropivacaine 7.5 mg/ml injected at each site, respectively, immediately prior to induction of general anesthesia. Standard postoperative analgesia with paracetamol 1 g every 6 hours and Morphine 5 mg as needed. Ondansetron or Metoclopramide as needed for nausea. | Procedure: Block of the SN and ONP<br>* 7.5 ml of Ropivacaine 7.5 mg/ml injected at each site<br>* Other names: Naropin;Drug: Paracetamol<br> <br> * Other names: Acetaminophen;Drug: Morphine<br>* 5 mg as needed<br>Drug: Ondansetron<br>* 4 mg i.v. as needed in the PACU<br>* Other names: Zofran;Drug: Metoclopramide<br>* 10 mg tablet as needed in the postoperative period after discharge from the PACU<br>* Other names: Primperan;|
| Placebo Comparator: Placebo arm<br>Ultrasound guided placebo block of the SN and ONP with 7.5 ml of isotonic saline solution injected at each site, respectively, immediately prior to induction of general anesthesia. Standard postoperative analgesia with paracetamol 1 g every 6 hours and Morphine 5 mg as needed. Ondansetron or Metoclopramide as needed for nausea. | Procedure: Placebo block<br>* 7.5 ml of isotonic saline solution 154 mmol/l injected at each site<br>* Other names: NaCl;Drug: Paracetamol<br> <br> * Other names: Acetaminophen;Drug: Morphine<br>* 5 mg as needed<br>Drug: Ondansetron<br>* 4 mg i.v. as needed in the PACU<br>* Other names: Zofran;Drug: Metoclopramide<br>* 10 mg tablet as needed in the postoperative period after discharge from the PACU<br>* Other names: Primperan;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain on knee flexion | VRS (Verbal Rating Scale) score 0-10 on active flexion of the knee to 45 degrees, measured at 0, ½, 1, 2, 3, 4, 6, 8, 12 and 24 hours postoperatively and analyzed by area under curve (AUC) analysis. | 24 hours postoperatively | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Pain at rest | VRS (verbal rating score) 0-10 at rest, measured at 0, ½, 1, 2, 3, 4, 6, 8, 12 and 24 hours postoperatively and analyzed by area under curve (AUC) analysis. | 24 hours postoperatively | 
| Time to opioid intake | First time the patient needs to take supplementary opioids in the postoperative period | 24 hours postoperatively | 
| Total opioid intake | Total dose of opioids taken in the first 24 hours postoperatively | 24 hours | 
| Nausea | VRS score 0-10, measured at 0, ½, 1, 2, 3, 4, 6, 8, 12 and 24 hours postoperatively and analyzed by area under curve (AUC) analysis. | 24 hours postoperatively | 
| Vomiting | Number of times the patient has vomited in the first 24 hours postoperatively. | 24 hours | 
| Use of antiemetics | Total dose of antiemetics taken during the first 24 hours postoperatively | 24 hours | 
| PACU length of stay | Total length of stay in the post anesthetic care unit (PACU) after the operation. | 24 hours | 
| Function level: Barthel Index/100 | Modified Barthel Index/100 score 24 hours after the operation. | 24 hours | 
| Function level: Short form (SF) -8 | Short form (SF) -8 questionnaire 24 hours postoperatively | 24 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Nerve block, Ultrasound, postoperative pain, Saphenous nerve, Obturator nerve