PROJECT SUMMARY Osteoarthritis of the knee is one of the most common causes of chronic pain in the US, and a common reason that patients take long-term opioids for pain. Total knee arthroplasty is often used to treat advanced knee osteoarthritis, with nearly a million patients undergoing total knee arthroplasty in the US each year. Many patients who undergo total knee arthroplasty are taking opioids preoperatively. However, preoperative opioid use is associated with worse postoperative pain, higher complication rates, and higher postoperative opioid use. Even low dose opioids can induce dependence and hyperalgesia, so postoperative pain can be harder to control in patients who have been taking chronic opioids, which can then lead to more difficult rehabilitation after surgery. Tapering opioids preoperatively holds potential to improve outcomes in total knee arthroplasty by counteracting these negative effects of opioids. However, the existing literature on preoperative opioid taper is limited. Several small retrospective studies have suggested a benefit, but detailed preoperative taper protocols have not been published, and high quality prospective studies have not been conducted. This proposal looks to advance the field of preoperative opioid tapering. Aim 1 will develop and refine a preoperative opioid taper protocol for patients undergoing total knee arthroplasty. Aim 2 will assess the feasibility of preoperative opioid taper intervention in a pilot randomized trial. At the completion of the pilot trial in Aim 2, the intervention will be ready to be tested for efficacy in a multicenter randomized control trial as the next step in this research. The overall goal of this 4-year Mentored Patient-Oriented Research Career Development Award (K23) proposal is to support Kevin Riggs, MD, MPH to become an independent investigator in the field of improving arthroplasty outcomes, with a focus on pain and opioid use. This award will provide comprehensive mentoring, training, and research experience to facilitate Dr. Riggs’s progression toward becoming an independent investigator. Specifically, Dr. Riggs will gain expertise in developing interventions, clinical trial design, and evaluation of functional status and other patient-reported outcome measures. This will position Dr. Riggs to become a leader in improving surgical outcomes for patients undergoing arthroplasty.