PROJECT SUMMARY Insufficient and poor sleep is pervasive among individuals with shoulder conditions requiring surgical intervention. Impaired preoperative sleep has been shown to induce hyperalgesia, predict the onset of painful episodes, and result in worse postoperative pain outcomes. Given the contributing role unmanaged acute pain has on developing chronic pain, patients with s hortened sleep and increased sleep disturbances (e.g., inefficient sleep) may be at greater risk for developing chronic post-surgical pain. Research shows the utility of pain trajectories to predict the development of chronic post-surgical pain, yet there is a dearth of research examining how changes in sleep contribute to the development of chronic post-surgical pain, despite evidence showing sleep impacts pain. One pathway through which poor sleep may contribute to chronic pain is through increased systemic inflammation. Shortened sleep and increased sleep disturbances induce an outsized inflammatory reaction, including upregulating cytokines, which sensitizes the nociceptive response and may increase susceptibility for developing chronic post-surgical pain. As many as 1 in 5 patients undergoing shoulder arthroplasty require prolonged opioid therapy for pain management. To date, postoperative opioid utilization has been assessed predominantly using patient self-report or dispensing records, with little known regarding real- time postoperative opioid use trajectories. This prospective study seeks to elucidate sleep presentations, as well as underlying inflammatory changes, that catalyze the acute to chronic pain transition after shoulder arthroplasty. This will be accomplished by leveraging actigraphy sleep-related data and medication utilization data collected daily using electronic monitoring from participants pre- and postoperatively and pairing those data with biopsychosocial outcomes and inflammatory markers up to 3-months later. This study aims to characterize and classify sleep trajectories prior to and after shoulder arthroplasty via actigraphy devices. Additionally, this study will examine the development of chronic post-surgical pain and real time opioid utilization, captured using Medication Event Monitoring Systems (MEMS) caps, across sleep trajectories. Finally, this study will compare longitudinal changes in inflammatory markers and subsequent development of chronic pain. These research aims reflect the PI’s career development objectives to develop expertise in the areas of cytokine research, implement actigraphy devices and MEMS into prospective studies for real-time objective data collection, analyze and visualize longitudinal data, and to develop vital leadership skills. This research, conducted under the guidance of an interdisciplinary team of mentors, will aid the PI in cultivating skills needed to advance as an independent scientist conducting clinical research optimizing symptoms to prevent chronic pain and prolonged opioid use postoperatively.