Abstract:To investigate the post-operative pain variance between patients receiving total knee replacement and total hip replacement.?Methods?A longitudinal study design was used with a sample of 150 subjects at a medical center in our hospital. The subjects were divided into two groups: one group received total knee replacement (TKR) and the other group had total hip replacement (THR). Structured questionnaires, pain assessment records regarding adverse effects due to pain and visual analog scale (VAS) were utilized for data collection and analysis for three post-operative days.?Results?The level of pain and occurrence of adverse effects due to pain decreased by time (P?0.05). The TKR group's pain level was higher than that of the THR group after surgery. Although the patients with minimally invasive surgery (MIS) had higher levels of pain compared with those who received traditional surgery during the post-operative 24 hours, the patients with MIS had significantly lower levels of pain 48 and 72 hours after surgery than the patients who had traditional surgery. In summary, patients with MIS had lower levels of pain. The main adverse reactions of pain in both groups were not to turn over, and the incidence of postoperative pain in THR group was higher than that in TKR group (t?=?15.62,P?=?0.000).?Conclusion?VAS can be used for patients' pain assessment after TKR and THR surgeries with the proper care measures provided.