With an increasing prevalence of osteoarthritis, total knee (TKA) and hip (THA) arthroplasty are the second-and third-most common surgeries in Canada. Although these procedures improve pain and function for a majority of patients, some patients report persistent postoperative pain. Opioids are conventionally used for these patients even though they are associated with addiction, falls, overdose, and death. Recently, many strategies have been proposed to decrease reliance on opioids after TKA and THA, including opioid-free and opioid-reduced multimodal protocols for pain management. Our findings demonstrate that Canadian patients’ receptivity to opioid-free or reduced postoperative protocols is associated with their perception of the efficacy and safety of opioids compared to non-opioid alternatives, and current opioid use. More patients are open to opioid-reduced postoperative care as they perceive that pain will be intolerable without opioids. This overlaps with many Canadian surgeons’ perception that opioids cannot be completely eliminated from postoperative pain management regimens and that patients expect an intolerable level of pain after surgery, warranting opioid use. This highlights a need for enhanced patient education on the safety and efficacy of opioids and alternatives, while managing patients’ expectations of postoperative pain control. Most Canadian and Dutch surgeons reported that they prescribe opioids to nearly all of their patients postoperatively. However, our cross-sectional study indicates that 40% of Canadian patients would be open to receiving no opioids postoperatively. In contrast, Japanese surgeons believed that opioids are unnecessary for managing postoperative pain. Variations observed among orthopaedic surgeons in Canada, the Netherlands, and Japan can be attributed to differences at the surgeon-level (individual practices and beliefs), patient-level (patient characteristics and preferences), and system-level (regulatory frameworks and healthcare systems). Further research is required on surgeon-centered approaches to mitigating opioid use, focusing on education and guidelines/policies for opioid prescribing. / Thesis / Master of Science (MSc) / Opioid analgesics are routinely prescribed to manage pain after total knee and hip replacement surgery. However, opioids are not typically more effective than alternatives and are associated with addiction, overdose, and death. This thesis aims to understand the perceptions of patients and orthopaedic surgeons on opioid use after total knee and hip replacement surgery. The findings demonstrate that more patients are open to receiving opioid-reduced surgery compared to opioid-free surgery, with receptivity being associated with patients’ perceptions of opioid efficacy and safety and current opioid use, highlighting a need for improved patient education. Additionally, orthopaedic surgeons identified challenges and facilitators to postoperative opioid reduction in six key areas: opioid prescribing practices, patient factors, collaborative care, policies/guidelines, surgeon education and training, and personal perceptions/beliefs. Compared to Canadian and Dutch surgeons, Japanese surgeons heavily relied on non-opioid medications as they believed that opioids are unnecessary for managing postoperative pain.