Popliteal Plexus Block for Postoperative Pain After ACL Reconstruction

Study Overview
=================
Brief Summary
-----------------
The study aims to investigate the effect of the popliteal plexus block (PPB) on postoperative pain in patients undergoing anterior cruciate ligament (ACL) reconstruction.

Detailed Description
-----------------
Postoperative pain following ACL reconstruction can be alleviated with an ultrasound-guided femoral triangle block (FTB). However, it is the investigators' observation that 10-20 % of the patients still complain of intense pain localized in the center of the knee. Cadaver dissection studies have shown that an injection into the distal part of the adductor canal will spread to the popliteal fossa, and one dissection study showed consistent spread to the popliteal plexus. The study team hypothesized that a PPB will reduce the postoperative pain, when it is used as a supplement to the FTB in patients undergoing ACL reconstruction.

Official Title
-----------------
The Effect of the Popliteal Plexus Block on Postoperative Pain After Reconstruction of the Anterior Cruciate Ligament

Conditions
-----------------
Anterior Cruciate Ligament Injury, Postoperative Pain

Intervention / Treatment
-----------------
* Procedure: Popliteal plexus block


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Patients undergoing ACL reconstruction on one of the two trial sites Age ≥ 18 American Society of Anesthesiologists (ASA) status I-III Informed consent Exclusion Criteria: Patients unable to cooperate Patients not able to speak Danish or with other communication problems Pregnancy Contraindication towards any medical product used in the study Preoperatively reduced sensation on the medial and lateral part of the lower leg Patients with diabetes requiring medical treatment Preoperative intake of opioids (dosed > once daily) ACL revision

Ages Eligible for Study
-----------------
Minimum Age: 18 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

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: Patients with postoperative pain, NRS >3<br>Patients reporting postoperative pain (NRS >3) localized to the center of the knee (10 patients) will receive a popliteal plexus block | Procedure: Popliteal plexus block<br>* 10 mL Marcain-adrenalin 5 mg/mL + 5 microgram/mL. Ultrasound-guided injection into the distal part of the adductor canal<br>|
| No Intervention: Patients with postoperative pain, NRS ≤ 3<br>(approx. 90 patients) | |

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| The effect of the popliteal plexus block (PPB) | Evaluated as the percentage of patients with postoperative pain NRS >3, dropping in pain score to NRS ≤ 3 after the PPB | Pain scores (NRS): 15, 30, 45 and 60 minutes after PPB | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Percentage of patients with central knee pain | The percentage of patients with FTB reporting pain (NRS >3) localized in the center of the knee in the observation period | Pain scores: 15, 30, 45 and 60 minutes after arrival at the post anesthesia care unit (PACU) | 
| Onset time for PPB | Time from withdrawal of the needle until patient reports NRS ≤ 3 | Pain scores (NRS): 15, 30, 45 and 60 minutes after PPB | 
| The effect of the PPB on cutaneous sensation | Tested on the lateral part of the lower leg (pinprick test) | Baseline, 30 and 60 minutes after PPB | 
| The effect of the PPB on muscle strength | Dorsal flexion and plantar flexion in the ankle joint, measured with a handheld dynamometer) | Baseline, 60 minutes after PPB | 

 Terms related to the study
=================
Keywords Provided by Centre Hospitalier Valida
-----------------
Peripheral nerve block, Ultrasound