Adductor Canal Block With IPACK Versus Genicular Nerves Block With IPACK for Post-operative Analgesia

Effective perioperative pain treatment has been documented to facilitate accelerated rehabilitation and recuperation, hence providing improved functional outcomes among individuals following knee surgeries. As a result, there has been a need to create multimodal analgesic regimens that include the usage of both regional anesthetic and systemic analgesics (Society, 2012).

Management of pain for knee surgery has been challenging, where various methods like epidural, peripheral nerve block (PNB), Local Infiltration Analgesia (LIA), intravenous (IV) analgesics like opioids, non-steroidal anti-inflammatory drugs (NSAIDs) and intra-articular (IA) injections, have been used (Tian et al., 2020).

In knee surgeries, the most difficult factor to control is pain, but early movement following surgery can be facilitated by motor-sparing regional anesthetic blocks and ultrasound-guided nerve blocks (Leung et al., 2018).

Perioperative multimodal analgesic strategies, consisting of "motor-sparing" regional anesthetic techniques combined with systemic nonopioid medications that target various pain pathways, have been developed to mitigate this risk; they confer improved pain scores and patient satisfaction, reduced opioid consumption and opiate-related adverse effects, early postoperative ambulation, shortened hospital stay, and fewer surgical complications (Kandarian et al., 2019).

The adductor canal block (ACB) is a regional anesthesia technique used to provide analgesia to the anterior and medial areas of the thigh and the knee (El-Boghdadly et al., 2021).

The ACB targets the nerves that pass through the adductor canal. The primary nerve target of the ACB is the saphenous nerve, a branch of the femoral nerve. The saphenous nerve is responsible for the sensitive innervation of the leg's medial section, from the knee to the ankle. In addition to the saphenous nerve, the ACB may also block the anterior branches of the obturator nerve and the medial femoral cutaneous nerve, which supply sensation to the medial section of the thigh (Woodworth et al.,2023).

Often, it is challenging to adequately anesthetize the posterior knee through regional technique for postoperative analgesia. Local anesthetic infiltration of the interspace between the popliteal artery and capsule of the posterior knee, known as the IPACK block, can be used to reduce pain after knee surgery. The IPACK block is a novel regional technique developed to provide analgesia to this area without compromising motor function (Elliott \& Thobhani, 2014).

The IPACK, combined with ACB, involves blocking the sensory nerves of the anterior, medial, and posterior knee, preserving motor function to encourage early ambulation and expedited rehabilitation (Sankineani et al., 2018).

The genicular nerves include branches from the femoral, common peroneal, saphenous, tibial, and obturator nerves which innervate the knee capsule (Kim et al., 2018).

The superolateral, superomedial, and inferomedial branches of the genicular nerve were reported to be in proximity to the periosteum of tibia and femur, and the superolateral, inferolateral, superomedial, and inferomedial quadrants of the anterior knee joint were shown to be innervated by superior lateral, inferior lateral, superior medial and inferior medial branches of the genicular nerve, respectively alongside the branches of peroneal and femoral nerves (Tran et al., 2018).

A genicular nerve block specifically targets these branches for postoperative analgesia in knee surgery.

First analgesic request (to evaluate the efficacy of combined ultrasound-guided IPACK with adductor canal nerve block versus ultrasound-guided IPACK with genicular nerves block on postoperative pain in knee arthroscopy) is the primary outcome of the study.

VAS score (dynamic and static), Hemodynamics (heart rate, blood pressure and SpO2), Total analgesic requirements, Time Up and Go test (for calculating time of postoperative movement) and Complications as (Nausea, vomiting, Allergy, Tachycardia, Hypotension or Local anesthetic toxicity) are the secondery outcomes.

Neurological deficiencies prior to surgery, Severe Cardiovascular, renal, hepatic comorbidities, Hematological disorders, abnormal coagulation parameters, Psychiatric illnesses, opioid addiction or Allergies to any of the medications will be utilized in the study will be excluded.

A prospective randomized controlled clinical study will be conducted in anesthesiology and intensive care department at Minia University Hospital (MUH) on 72 adult patients of both genders, aged between 20 years to 70 years old, ǀ and ǀǀ classification of The American Society of Anesthesiologists (ASA) planned to undergo elective unilateral knee surgeries under spinal anesthesia.

Patients will be divided into 3 groups, each group includes 24 patients: