Genicular Nerve Blocks for Anterior Cruciate Ligament Knee Surgery

Genicular Nerve Blocks for Arthroscopic Anterior Cruciate Knee Surgery: a Randomized Controlled Trial

The purpose of this randomized controlled trial is to assess a new analgesia regimen that includes the addition of genicular never blocks to our current standard regimen of peripheral nerve blocks, which includes an adductor canal block (ACB) and interspace between the popliteal artery and capsule of the posterior knee block (IPACK). The main questions it aims to answer are: Does addition of genicular nerve blocks to standard peripheral block regimen significantly reduce the mean opioid consumption by 33% in the first 24 hours? Does genicular nerve blocks reduce NRS pain scores? Does genicular nerve blocks facilitate earlier discharge? Does genicular nerve blocks last longer than 24 hours? Does genicular nerve blocks improve pain management? Eligible patients are those undergoing an anterior cruciate ligament repair at the Hospital for Special Surgery and participants will be randomized to receive the intervention (genicular nerve block) or the standard of care.

Genicular nerve blocks have been shown to provide effective analgesia for chronic osteoarthritis knee pain. There are several publications supporting its use for chronic knee pain but there is a scarcity of literature in its use in the perioperative period. Recently, it has been shown to provide effective analgesia for total knee arthroplasty. This will be a novel application for it to be used for anterior cruciate ligament surgery. There are only a couple of prospective and retrospective studies that showed promising analgesic benefits for anterior cruciate ligament repairs. There are currently no randomized controlled trials published investigating the use of genicular nerve blocks for anterior cruciate ligament surgery. Researching novel innovative motor-sparing and opioid-sparing peripheral nerve blocks for have been the focus of research. Studies have investigated the motor sparing benefits of the adductor canal block, the effective analgesic benefits of the IPACK block, the phrenic sparing benefits of the superior trunk block, and the analgesic benefits of the pericapsular nerve group block and lateral femoral cutaneous nerve. Genicular nerve blocks would be a potential additive block that may further enhance the recovery of patients undergoing knee surgeries, including unicondylar, total knee and anterior cruciate ligament repair patients.

The patient, research assistants, and biostatisticians are blinded to whether the patient was randomized to the control or intervention group.

Patients randomized to this group will receive an adductor canal block (ACB) and Infiltration between the Popliteal Artery and Capsule of the Knee (IPACK) nerve block.

Patients randomized to this group will receive an adductor canal block (ACB), Infiltration between the Popliteal Artery and Capsule of the Knee (IPACK) nerve block, and the genicular nerve block (intervention). The genicular nerve block is a total of 20cc of 0.25% bupivacaine with 2mg of preservative free dexamethasone applied to the superomedial genicular nerve, superolateral genicular nerve, inferomedial genicular nerve, and nerve to vastus intermedius.

A genicular nerve block is a peripheral nerve block that temporarily anesthetizes the sensory terminal branches innervating the knee joint by injecting local anesthesia. This results in anesthesia of the anterior compartment of the knee. The genicular nerve block consists of 20cc of 0.25% bupivacaine with 2mg of preservative free dexamethasone and will be applied to the superomedial genicular nerve, superolateral genicular nerve, inferomedial genicular nerve, and nerve to vastus intermedius. Bupivacaine - Drug class: Sodium channel blocker Dexamethasone - Drug class: Glucocorticoid

IV and PO opioid consumption at 24 hours after surgery will be recorded. The average consumption across all participants will be reported.

IV and PO opioid consumption up to 168 hours after surgery will be recorded from the medical record and patient reported phone calls Although recorded at different timepoints, the average opioid consumption will be calculated and reported.

PACU(PACU arrival time to removal from board), 48,72,96,168 hours after time zero (PACU arrival time)

Patient scores at rest and with movement will be recorded. Scale of 0 to 10, with 0 meaning "no pain" and 10 meaning "worst pain imaginable". Lower score means less pain, higher score means greater pain. Although recorded at different timepoints, the average pain score will be calculated and reported.

total number of opioid pills taken will be recorded up to 168 hours after surgery. Although recorded at different timepoints, the average number of opioid pills will be calculated and reported.

sum of opioid used from 0-24 hours, 0-48 hours, and 0-72 hours, 0-96 hours, and 0-168 hours post-operative

This questionnaire will assess severity of pain, impact of pain on daily function, location of pain, medication intake, and amount of pain relief at 24 hours, 48 hours, and 96 hours after surgery. Questions are rated on a scale of 0 to 10, with 0 meaning "no pain" and 10 meaning "pain as bad as you can imagine". Although recorded at different timepoints, the average pain score will be calculated and reported.

patient satisfaction with study and pain treatment will be assessed in the post-operative care unit (PACU), 24 hours, and 48 hours after surgery. Although recorded at different timepoints, the average satisfaction score will be calculated and reported.

From the time patient arrived in the post-operative care unit (PACU), at 24 hours, and at 48 hours post-operative

To assess when the patient believe the analgesic block wore off and they regain sensation in their leg. Although recorded at different timepoints, the average will be calculated and reported.

numbness in the saphenous distribution will be assessed in the PACU by an anesthesiologist or research assistant

The time the patient arrived in the post-operative care unit (PACU) assessed up to 24 hours after surgery.

The duration from PACU arrival time to recovery complete time. The average time (in minutes) that it took for the patient to be discharged will be calculated and reported.

From the time the patient arrived in the post-operative care unit (PACU) arrival time to the time the patient is discharged(discharge ready time = recovery complete time) assessed up to 24 hours after surgery.

The duration from PACU arrival time to patient removed from board time. The average time (in minutes) will be calculated and reported.

From the time the patient arrived in the post-operative care unit (PACU) arrival time to the time they leave the PACU assessed up to 24 hours after surgery.

Incidence of neuropraxia (neurological symptoms over 3 days), local anesthetic systemic toxicity (LAST), and infection. The average number of adverse events will be calculated and reported.

Inclusion Criteria: Age 18 - 80 English speaking American Society of Anesthesiologists (ASA) I - III BMI < 35 Scheduled for ambulatory arthroscopic unilateral anterior cruciate ligament repair surgery with bone tendon bone autograft Exclusion Criteria: History of chronic pain syndromes Chronic opioid use (daily morphine milligram equivalents > 30 mg for at least 3 months) Contraindication to peripheral nerve blocks Contraindication to neuraxial anesthesia History of peripheral neuropathy or pre-existing neurological deficits Psychiatric or cognitive disorder that prohibit patient from following study protocol Allergy to local anesthetic or study medications Multi-ligament surgery History of substance abuse Infection at the site of injection

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