The Effect of Subsartorial Saphenous Block on Postoperative Pain Following Major Ankle and Hind Foot Surgery

Study Overview
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Brief Summary
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The study investigates the effect of a ultrasound-guided subsartorial saphenous block on postoperative pain following major ankle and hind foot surgery.

Detailed Description
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Major ankle and hind foot surgery causes intense postoperative pain. Implementation of continuous sciatic catheters has been a great success in reducing postoperative pain following these operations, but despite an effective sciatic catheter patients still report moderate to severe pain from the anteromedial side of the ankle. According to cadaver dissection studies the saphenous nerve innervates the anterior and medial parts of the ankle and talonavicular joint, and even though a saphenous block is standard procedure in many departments of anesthesiology worldwide, scientific evidence regarding the effect of the saphenous block on postoperative pain is lacking. This study investigates the effect of a selective, ultrasound-guided subsartorial saphenous block on postoperative pain following major ankle and hind foot surgery.

Official Title
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The Effect of Subsartorial Saphenous Block on Postoperative Pain Following Major Ankle and Hind Foot Surgery

Conditions
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Arthrosis, Arthritis

Intervention / Treatment
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* Drug: Bupivacaine-epinephrine
* Other: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Elective ankle or hind foot surgery either: (1) total ankle arthroplasty, (2) ankle arthrodesis (3) subtalar arthrodesis or (4) triple arthrodesis Age ≥ 18 American Society of Anaesthesiology Classification I-III Informed consent both orally and in writing after the patient has fully understood the protocol and its limitations. Exclusion Criteria: Communication problems or dementia Allergies to any medical product used in the study Neuropathy of the sciatic or femoral nerve prior to the operation Morbus Charcot-Marie-Tooth disease, diabetic neuropathy, peripheral vascular disease Daily use of opioids Coagulation disorders Infection at the site of injection or systemic infection

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 85 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: Bupivacaine-epinephrine<br>10 mL of 5 mg/mL bupivacaine with 5 μg/mL epinephrine = 50 mg bupivacaine and 50 μg epinephrine | Drug: Bupivacaine-epinephrine<br>* 50 mg bupivacaine and 50 μg adrenalin<br>* Other names: Marketing Authorisation number: 10213;|
| Placebo Comparator: Placebo<br>10 ml normal saline water (sodium chloride solution, 0,9%) | Other: Placebo<br>* 9 mg sodium chloride pr. ml (0,9 %)<br>* Other names: Sodium chloride solution;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Frequency of patients who experience significant pain at rest (change from no significant pain to significant pain) | Pain scores evaluated using NRS (numeric rating scale). Significant pain is defined as NRS > 3 from the anterior and/medial side of the ankle joint. In case of significant pain, patients receive a rescue saphenous block with 10 ml bupivacaine-adrenaline. | Arrival at the Perioperative Section (within 30 minutes after surgery) and at t = 30 min, t = 45 min, t = 60 min, t = 75 min, t = 90 min, t = 105 min, t = 120. The beginning of the observation period (t0) is the registered time for the end of surgery. | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Sensory testing, infrapatellar branch (nociception is tested using a standardized Neuropen) | Test of nociceptive response in the cutaneous innervation area of the infrapatellar branch (branch of the saphenous nerve). The test is performed in an area from the medial femoral condyle to the midline between the apex of patella and tibial tuberosity. | At the time point when the patients report a change to significant pain during the observation period. In case of no significant pain during the observation period, sensory testing is conducted at t = 120 min. | 
| Sensory testing, sciatic nerve (nociception is tested using a standardized Neuropen) | Test of nociceptive response in the sciatic cutaneous innervation area to confirm full sensory block of the sciatic nerve. | Sensory test is conducted at arrival at the Perioperative Section (within 30 minutes after surgery) |