One hundred and one patients undergoing elective total knee arthroplasty under spinal anaesthesia were randomized to receive either intranasal dexmedetomidine (n=49) or intranasal saline placebo (n=52). The primary outcome was postoperative pain measured using the numerical rating scale (NRS) during the first 24 hours. Secondary outcomes included postoperative opioid requirements, additional intraoperative sedation, perioperative haemodynamic stability, postoperative nausea and vomiting, and patient satisfaction at 30 days. Overall, the results showed that the dexmedetomidine group had significantly lower pain scores at 3 hours postoperatively, reduced intraoperative midazolam use, and higher patient satisfaction in the ward. However, cumulative 24-hour opioid requirements and other secondary outcomes did not differ significantly. These findings suggest that intranasal dexmedetomidine may reduce early postoperative pain and improve short-term satisfaction in TKA patients without significant haemodynamic or adverse effects.