Local Anesthetic-Induced Myotoxicity After Continuous Adductor Canal Block

Objective: Local anesthetic-induced myotoxicity occurs consistently in animal models, yet is reported rarely in humans. Herein, we describe 3 sentinel cases of local anesthetic myotoxicity after continuous adductor canal block (ACB). Case Report: Three patients underwent total knee arthroplasty that was managed with subarachnoid block plus ACB induced with 1.5% lidocaine or 1.5% mepivacaine bolus followed by 0.2% ropivacaine at 8 mL/h. Although initial postoperative recovery was normal, each patient on either postoperative day 1 or 2 developed progressive, profound weakness of the quadriceps muscles. Clinical course, imaging, and neurophysiologic studies were consistent with myositis. The patients experienced partial to full functional recovery over the ensuing weeks to months. Conclusions: Clinically apparent local anesthetic-induced myotoxicity has been documented rarely in humans undergoing non-ophthalmic surgery. We report 3 sentinel cases associated with continuous ACB.