Efficacy of systemic lidocaine versus ultrasound-guided adductor canal block for patients undergoing total knee arthroplasty: a randomized, double-blinded, non-inferiority study

Why clinicians should know about it

• Picked for Orthopedics and Sports Medicine (top studies of the week, 2 August 2026).

Abstract

BACKGROUND: Total knee arthroplasty (TKA) is associated with significant postoperative pain; therefore, adductor canal block is commonly used as part of multimodal analgesia. Intravenous lidocaine may provide a practical alternative when regional anesthesia is not feasible. This study compared intravenous lidocaine with ultrasound-guided adductor canal block for postoperative opioid consumption, pain scores, and quality of recovery within the first 24 hours after outpatient TKA. METHODS: In this non-inferiority trial, 120 patients undergoing TKA were randomized 1:1 to receive either a single injection adductor canal block with saline infusion or intravenous lidocaine infusion with sham block. The primary outcome was opioid consumption 24 hours after surgery, with a prespecified non-inferiority margin of 30 mg oral morphine equivalents (OME). Secondary outcomes included pain scores, time to first analgesic request, quality of recovery, and patient satisfaction. RESULTS: Median OME consumption was 57.5 mg (IQR 37.5-77.5) in the lidocaine infusion group and 52.5 mg (IQR 30-77.5) in the adductor canal block group, with a median difference of 5.0 mg (95% CI -11.2 to 16.2), below the prespecified non-inferiority margin. In post-anesthesia care unit (PACU), median opioid consumption and pain scores at discharge were lower in the adductor canal block group than in the lidocaine group, with a median difference of 10 mg OME (95% CI 1.0 to 11.2; p=0.02) and two points (95% CI 0.33 to 4; p=0.02), respectively. There were no study-related adverse events. Time to first analgesic request, quality of recovery, and patient satisfaction were similar between groups. CONCLUSIONS: Continuous intravenous lidocaine was non-inferior to adductor canal block for postoperative analgesia at 24 hours after TKA. Although adductor canal block provided better immediate PACU analgesia, both strategies were comparable thereafter, supporting lidocaine as a useful option when regional anesthesia is not feasible.

Abstract as published, via PubMed.