The aim of this study was to evaluate whether perioperative probiotics can reduce the incidence of postoperative cognitive dysfunction and postoperative delirium.

Inclusion Criteria:

1. . Age is greater than or equal to 65 years old
2. . Can communicate normally
3. . Selective knee ankle, hip replacement or lumbar open reduction and internal fixation under general anesthesia
4. . ASA graded at I-II level
5. . Patient or family informed consent

Exclusion Criteria:

1. . Have a brain disease, or have a history of brain disease
2. .MMSE check of less than 24 points.
3. . History of neurological and psychological disorders including AD, stroke, psychosis
4. . Serious hearing or visual impairment
5. . Preoperative systolic blood pressure >190mmhg, or diastolic blood pressure >100mmhg
6. . The patient or family refuses