4. Discussion
postoperative pain, nausea and vomiting, pain, urinary retention, TKA, drug dependence
CHRONIC PAIN, RESPIRATORY DEPRESSION, POSTOPERATIVE COMPLICATIONS
Perioperative pain management is key to the smooth implementation of enhanced recovery after surgery (ERAS), which has rapidly become a popular concept in the field of orthopedics. Although the combined application of various postoperative analgesia methods can improve the postoperative acute pain of TKA patients, many still suffer from moderate or even severe pain [Preemptive analgesia is an important part of multimodal analgesia, and its value is increasingly recognized by clinicians and researchers. Some studies have found that preemptive analgesia can further improve postoperative pain in TKA patients [In the present study, we observed that the combination group had better improvement in pain scores at rest and upon movement than the other three groups. The pain scores at rest in the combined group were always low level within 48 hours, and unlike the placebo group, there were no large fluctuations in pain scores, which indicated that the analgesic effect of the combination regimen was stable and relatively durable. However, the pain upon movement was more significant than that at rest because all of the patients need to exercise as soon as possible after TKA to enhance recovery. In the study of Lee et al. [Currently, analgesia after TKA mainly involves a variety of opioids, such as sufentanil, tramadol, and morphine. Opioids mainly act on opioid receptors in the pain center of the brain to inhibit the generation and amplification of pain signals. However, opioids have significant side effects, such as nausea and vomiting, drug dependence, urinary retention, excessive sedation, and respiratory depression. The majority of TKA patients are elderly patients, and the incidence of opioid side effects is significantly higher in elderly patients than in young and middle-aged patients [The key core of preemptive analgesia is to reduce the degree of peripheral and central pain sensitization and to improve the pain threshold of patients in advance [Our study has some limitations. First, our research was limited to within 72 hours after surgery, so we cannot be sure whether control of acute postoperative pain can promote long-term knee function recovery and reduce the possibility of long-term chronic pain. Second, we did not accurately estimate sample size, which may affect the efficacy of the present study. Third, according to the relevant study [Last, in terms of postoperative complications, our sample size was too small to comprehensively and objectively evaluate the safety of analgesia programs.