Anesthesia and Perioperative Neurocognitive Disorders in the Elderly Patients Undergoing Hip Fracture Surgery Platform Trial (ANDES Platform Trial)

Inclusion Criteria:

1. Aged 65 years and older.
2. Patients with unilateral hip fracture (including femoral neck, femoral head, intertrochanteric and subtrochanteric fractures) are scheduled for surgical treatment.
3. American Society of Anesthesiologists (ASA) physical status IV or below.
4. The patients or family members provide written informed consent.
5. Additional inclusion criteria may pertain to specific interventions and will be described in relevant sub-protocols.

Exclusion Criteria:

1. Patients with multiple trauma or fractures (excluding trauma that the researcher judges will not affect the patient's overall recovery, such as simple spinal compression fractures, mild soft tissue contusions, fractures of hands and feet, etc.);
2. Two or more anesthetic surgeries are required.
3. Patients with an obvious history of head trauma (such as loss of consciousness for more than 5 minutes, post-traumatic amnesia, etc.);
4. Patients who the researcher believes are unable to complete the assessment of primary outcome;
5. Additional exclusion criteria may pertain to specific interventions and will be described in relevant sub-protocols.

Additional exclusion criteria for the nerve block randomization:

1. Contraindications to nerve block, including allergy to local anesthetics, other contraindications specified in the applicable prescribing information, infection at the puncture site, or refusal to receive nerve block;
2. The investigator considers the participant unsuitable for nerve block because of conditions such as a history of severe peripheral neuropathy or severe coagulation dysfunction;
3. Receipt of nerve block before randomization during the current hospitalization.

Additional exclusion criteria for the intravenous lidocaine randomization:

1. Allergy to lidocaine;
2. Severe hepatic impairment or renal insufficiency for which the investigator considers the participant unsuitable for enrollment.

Eligibility Criteria for nonsurgical cognitive control participants:

A nonsurgical cognitive control cohort may be recruited from emergency departments, outpatient clinics, inpatient wards, or the community for standardization of neurocognitive assessments. These participants will be matched as far as possible to surgical participants by age and education level. Except for criteria related to hip fracture surgery and trial interventions, the same general inclusion and exclusion criteria will apply. Nonsurgical cognitive control participants must not undergo surgery or anesthesia during the observation period; participants who undergo surgery during follow-up will be excluded from the nonsurgical cognitive control cohort.