Leveraging Large Language Models to Automate and Improve Accuracy of Medical Registry Curation - ABSTRACT Registries are by far the most important source of data for orthopedics, particularly joint replacement. The importance of registries surpasses even randomized clinical trials (RCT) due to the long duration of postoperative surveillance, the substantial costs associated with the procedures and implants under investigation, and the heterogeneity that exists across institutions, regions, and countries. Unfortunately, building a large-scale and comprehensive registry is difficult. On one hand, comprehensive datasets usually result from expensive small cohort projects such as the Osteoarthritis Initiative (OAI). Universal implementation of this model is not feasible as smaller institutions might not have the resources to employ the required personnel or build the extensive initial infrastructure. On the other hand, nationwide registries such as Medicare databases are comparatively sparse and unhelpful. In orthopedics, large-scale registries like the American Joint Replacement Registry (AJRR) face challenges of data contribution. Participation is currently voluntary and the fractionated nature of the US healthcare system limits the data quality of contributions. Thus, the balancing act in registry construction is between comprehensive depth and participation/completeness. If data points are too onerous to abstract, participation will be low; if completeness is prioritized, interesting data points are difficult to include. To solve both these problems and take the next step in national-scale registry construction, we will develop automatic methods of data abstraction. The potential time and cost benefits of an entirely automated abstraction pipeline are immense, in addition to allowing for registries to easily scale to accommodate the records produced by the millions of arthroplasties performed nationwide. Our central hypothesis is that large language models, with proper fine-tuning, grounding, and prompting, can acquire trustworthy orthopedic-specific performance enabling them to interpret clinical notes for data extraction and complex synthesis tasks. Successful completion of this aim will yield fine-tuned LLMs capable of 1) efficiently and accurately extracting critical data for automated orthopedic registry curation, and 2) interpreting clinical notes for patient-specific phenotyping. These advancements are anticipated to reduce barriers to clinical registry construction and increase the comprehensive depth of registry data, encouraging cross-institutional collaborations on significant health issues. Additionally, increased registry participation will facilitate the integration of pragmatic and nested RCTs within registries, enabling prospective data collection and generation of high-level evidence to refine surgical techniques and implant design, ultimately improving patient outcomes.