Limitations
delirium, fracture
1. This study restricted the study population to elderly hip fracture patients undergoing hip arthroplasty under spinal anesthesia. For other relevant populations, such as elderly patients undergoing surgery under general anesthesia or undergoing internal fracture fixation, the results of this study may be applicable, but further studies are needed. 2. The evaluation of postoperative analgesia was based on the subjective feelings of patients. The data of post-operative opioids consumption were not collected. 3. This study was followed up to 48 h after the operation. Further research is needed on the impact of a longer time, such as the impact on the incidence of postoperative cognitive function and postoperative delirium.