Many patients following total knee arthroplasty (TKA) complain moderate to severe postoperative pain. Multimodal analgesia, a combination of different techniques and analgesic agents, plays an increasingly important role to relieve pain after TKA. Femoral nerve block (FNB) is a first-line analgesic technique for multimodal analgesia after TKA. But local anesthetics alone often exert limited potency of analgesia and are insufficient to avoid supplemental opioid usage. Dexmedetomidine, a selective alpha 2-adrenergic receptor agonist, is widely used in clinical settings due to its properties of sedation, anxiolysis, analgesia, and sleep promotion. Recent studies and meta-analysis indicate that dexmedetomidine combined with local anesthetics for FNB can prolong the analgesic duration, improve the analgesic efficacy, inhibit local inflammatory response, and reduce narcotic consumption. The investigators hypothesize that dexmedetomidine combined with ropivacaine for FNB can also improve the functional recovery in aged patients after TKA.
Femoral nerve block (FNB) is a first-line analgesic technique for multimodal analgesia after total knee arthroplasty (TKA). Recent studies and meta-analysis indicate that dexmedetomidine combined with local anesthetics for FNB can prolong the analgesic duration, improve the analgesic efficacy, inhibit local inflammatory response, and reduce narcotic consumption. The investigators hypothesize that dexmedetomidine combined with ropivacaine for FNB can also improve functional recovery in aged patients after TKA.