The Effect of Popliteal Plexus Block on Pain After Total Knee Arthroplasty

Study Overview
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Brief Summary
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The study aims to investigate the effect of the Popliteal plexus block (PPB) on postoperative pain after total knee arthroplasty

Detailed Description
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Cadaver dissection studies have shown a spread of dye to the popliteal fossa and colored the popliteal plexus by injecting in the distal part of the adductor Canal. The popliteal plexus is formed by contribution from the tibial and the obturator nerves. Investigators hypothesized that a PPB may reduce postoperative pain after total knee arthroplasty.

Official Title
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The Effect of Popliteal Plexus Block on Postoperative Pain After Total Knee Arthroplasty

Conditions
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Popliteal Plexus Block, Total Knee Arthroplasty

Intervention / Treatment
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* Drug: Bupivacaine-epinephrine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: patients undergoing total knee arthroplasty in spinal anesthesia age > or = 18 years American Society of Anesthesiologists (ASA) status I-III Informed consent Exclusion Criteria: Patients unable to cooperate Patients not able to speak Danish Pregnancy Contraindication towards ana Medical product used in the study Preoperatively reduced sensation on the medial and lateral part of the lower leg Patients with diabetic requiring Medical treatment Preoperative daily intake of opioids

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: Non-Randomized
Intervention Model: Parallel Assignment
Interventional Model Description: Pilot Study
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Popliteal plexus block<br>Patients with an FTB, reporting postoperative pain (NRS > 3) will have a popliteal plexus block | Drug: Bupivacaine-epinephrine<br>* Popliteal plexus block with 10 mL of bupivacaine-epinephrine 5 mg/mL + 5 microgram/mL.<br>|
| No Intervention: No intervention<br>Patients with postoperative pain NRS < or = 3 | |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The percentage of patients with postoperative pain NRS | Evaluated as the percentage of patients with postoperative pain NRS >3, dropping in pain score to NRS = or < 3 after the PPB | 0 - 60 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of patients having a femoral triangle block(FTB) reporting NRS > 3 | Percentage of patients having a FTB, reporting postoperative pain NRS >3 | Pain scores every 15 minutes (from end injection FTB to NRS>3 or 3 hours after full sensation of the leg) | 
| Onset time of PPB | Time from end of injection of PPB to NRS = or < 3 | NRS every 5 minutes after PPB (From 0 - 60 minutes after PPB) | 
| Turn off time of spinal anesthesia | Time from arrival in PACU to normal cutaneous sensation (measured by a neuro-pen, sensation=point 2) on the lateral part of the thigh and lateral part of the lower leg | Time from arrival in PACU and during maximum 6 hours | 
| Correlation between normal cutaneous sensation and developing of pain | Correlation between normal cutaneous sensation (measured by a neuro-pen, sensation=point 2) and developing of pain (NRS>3) | From arrival in PACU and during maximum 6 hours | 
| The effect of the PPB on cutaneous sensation | Tested on the lateral part of the lower leg | NRS every 5 minutes after PPB (From 0 - 60 minutes after PPB) | 
| The effect of the PPB on muscle strength of the foot | Dorsal flexion and plantar flexion in the ankle joint, measured with a handheld dynamometer | Baseline and 1 hour after PPB |