ACB Versus IA Analgesia in Knee Arthroscopy

Adductor Canal Block Versus Intra-articular Analgesia for Postoperative Pain After Arthroscopic Anterior Cruciate Ligament Reconstruction: a Randomized Trial

Reconstruction of the anterior cruciate ligament (ACL) of the knee is a painful procedure, and effective postoperative analgesia is important for early return of patient activity.

Reconstruction of the anterior cruciate ligament (ACL) of the knee is a painful procedure, with postoperative analgesia providing patient comfort, early mobilization, and discharge within 24 hours. Various methods for postoperative analgesia management are available, such as systemic opioids, epidural local anesthetic, peripheral nerve block and local anesthetic infiltration analgesia. Use of systemic opioids can cause adverse effects that may affect functional rehabilitation, such as nausea, vomiting, pruritus, sedation and respiratory depression. Hypotension, urinary retention, and pruritus are more common in patients with epidural analgesia. In addition, use of long-acting intrathecal opioids causes adverse effects such as bilateral motor block, tremor and hypotension. Systemic and intrathecal methods for postoperative analgesia are gradually being abandoned because of these negative effects. The saphenous nerve is the largest contributor to sensory perception around the knee, while the adductor canal contains the nerve to the vastus medialis, the medial femoral cutaneous nerve, the medial retinacular nerve, articular branches from the posterior division of the obturator nerve and occasionally the anterior branch of the obturator nerve. Although adductor canal block (ACB) can contribute towards motor blockade of the periarticular musculature, its effect on functional weakness of the quadriceps has been reported to be minimal, compared with femoral nerve block (FNB). Intra-articular (IA) local anesthetic agents have been used either alone or in combination with other agent. However, it was observed that use of combination of drug is better than single drug for prevention of postoperative pain, providing synergistic effect and reducing side effects compared to high dose of single drug. Levobupivacaine, the S-enantiomer of bupivacaine is a comparatively newer local anesthetic agent introduced into clinical practice and it also possesses less cardiac and neural toxicity. Levobupivacaine has been shown to be safe and effective for epidural and spinal anesthesia and blockade of the brachial plexus. Dexamethasone is a potent and highly selective glucocorticoid with minimal mineralocorticoid effect. It blocks the nociceptive impulse transmission along the myelinated C fibers. Dexamethasone prolongs the duration of regional blocks, when combined with local anesthetics.

Patients will receive ultrasound-guided (USG) ACB with levobupivacaine and dexamethasone 30 minutes before spinal anesthesia and sham intra-articular normal saline.

Patients will receive intra-articular levobupivacaine and dexamethasone at the end of surgery and sham USG-ACB with normal saline.

Patients will receive ultrasound-guided (USG) ACB with levobupivacaine and dexamethasone 30 minutes before spinal anesthesia and sham intra-articular normal saline

Patients will receive intra-articular levobupivacaine and dexamethasone at the end of surgery and sham USG-ACB with normal saline

Inclusion Criteria: Patients undergoing elective arthroscopic reconstruction of the anterior cruciate ligament (ACL) under spinal anesthesia, aged from 18 to 65 years old Exclusion Criteria: Contraindications to peripheral nerve block (e.g. allergy to local anesthetics, coagulopathy, infection in the area) History of cardiovascular, cerebrovascular, and respiratory diseases Preexisting neuropathies Chronic pain syndrome Opioid dependence Patients with diabetes mellitus, sever hypertension, hepatic or renal dysfunction Pregnancy Preoperative inability to perform the mobilization test (TUG test) Not willingness to participate.