Total knee arthroplasty is increasingly common worldwide, but many patients still struggle with moderate to severe postoperative pain. Femoral nerve block is a widely used strategy to manage this pain, and interest has grown in whether adding dexmedetomidine—a sedative-analgesic agent—can further improve outcomes. Across six randomized trials, dexmedetomidine as an adjuvant offered small but consistent reductions in pain during movement and modest benefits at rest, along with lower opioid requirements. These improvements, however, did not exceed minimal clinically important thresholds. Safety outcomes were similar between groups, with no increase in hypotension, bradycardia, or nausea. Overall, adding dexmedetomidine appears to enhance analgesia without added risk, though the clinical impact remains modest and more high-quality research is needed.