1. Eligible patients are randomly divided into experimental and control groups；
2. The experimental group is given esketamine combined with dexmedetomidine，while the control group is given normal saline；
3. The patients' sleep, pain, and cognition are followed up after surgery.

One day before surgery, the investigators collect baseline data from patients at the bedside. Preoperative sleep quality is assessed using Pittsburgh sleep quality index(PSQI); Three-Minute Confusion Assessment Method(3D-CAM)is used to assess the incidence of delirium; cognitive function is assessed using Montreal Cognitive Assessment(MoCA); The Hospital Anxiety and Depression Scale (HADS) is used to assess patients' mood; Wong-Baker faces pain scale revision(FPS-R) and Numeric Rating Scale(NRS) are used to assess the patient's pain score at rest and during activity, and laboratory tests (Hb, Alb, K, NA, Cr, Alb, e-GFR) are recorded.

On the day of surgery, after successful neuraxial anesthesia, in the experimental group ，0.125mg/kg esketamine and 0.3ug/kg dexmedetomidine are diluted into 30ml of normal saline and continuously pumped for 20 minutes, followed by a micropump: 15ug/kg/h esketamine 0.02ug/kg/h dexmedetomidine to 96ml saline, continuous amount: 2ml/h, continuous pumping for 48h. Morphine 1 mg is given epidural at the beginning of surgery；while in the control group, same amount of normal saline is given. The patients are followed up for sleep quality, pain and delirium incidence after surgery. Long-term telephone follow-up of patients are focused on their cognitive function and recovery quality.

Inclusion Criteria:

• Age≥ 65 years old;
• Hip fracture surgery under neuraxial anesthesia;
• Signed informed consent.

Exclusion Criteria:

• ASA classification≥ Class V;
• Presence of neuraxial anesthesia contraindications: coagulation dysfunction, thrombocytopenia, neuraxial mass, puncture site infection, etc.;
• Patients with contraindications to esketamine (such as allergies, intracranial aneurysms, hyperthyroidism and glaucoma);
• Patients with contraindications to dexmedetomidine (allergies);
• Patients with severe cardiovascular diseases such as sick sinus syndrome, severe sinus bradycardia (heart rate < 50 beats/min), atrioventricular block grade II or above without pacemaker, unstable angina, severe valvular heart disease, severe arrhythmia, severe macrovascular disease with New York Heart Association class III patients, etc.;
• Obstructive sleep apnea syndrome (STOP-BANG score > 3 points);
• Patients with severe hepatic and renal insufficiency (such as Child-Pugh score III, creatinine clearance < 35 mL/min, preoperative dialysis);
• Those who have delirium, dementia, moderate to severe cognitive dysfunction and psychiatric disorders before the start of the trial and are unable to communicate and cooperate with the investigator.