Evaluating the Efficacy of Dexmedetomidine as an Adjunct to Local Anesthetics in Adductor Canal Blocks for Adult Patients Undergoing Primary Total Knee Arthroplasty: A Systematic Review and Meta-Analysis.

Over 700,000 total knee arthroplasties (TKAs) are performed in the United States annually. Long-term functional recovery following TKA depends heavily on early ambulation and rehabilitation, which requires effective pain management. Adductor canal blocks (ACBs) offer targeted analgesia while preserving quadriceps strength. However, postoperative pain often outlasts single-shot peripheral nerve blocks. This analysis evaluated whether perineural dexmedetomidine added to local anesthetics increased the efficacy and duration of ACBs in patients undergoing TKA. This systematic review and meta-analysis examined adult patients undergoing primary TKA under general or spinal anesthesia and ACB. Five randomized controlled trials examining 445 patients met inclusion criteria. Patient ages ranged from 18 to 85 years and demonstrated similar comorbidities. Pooled analysis showed that patients receiving dexmedetomidine reported lower pain scores at rest (mean difference [MD] -0.35; P = .009) and during activity (MD -0.40; P < .0001). Opioid consumption decreased by an average of 8.91 mg (P = .05). Time to first rescue analgesia increased by 1.54 hours, and ambulation outcomes consistently showed improvement in the dexmedetomidine group. This analysis supports the use of dexmedetomidine as an adjunct for ACB in TKA. However, significant heterogeneity among studies limits applicability of this analysis's findings. Clinicians are advised to consider this when making practice decisions.