BACKGROUND: Use of clinical and administrative databases in orthopaedic surgery research has grown substantially in recent years. It is estimated that approximately 10% of all published lower extremity arthroplasty research have been database studies. The aim of this review is to serve as a guide on how to (1) design, (2) execute, and (3) publish an orthopaedic administrative database arthroplasty project. METHODS: In part I, we discuss how to develop a research question and choose a database (when databases should/should not be used), detailing advantages/disadvantages of those most commonly used. To date, the most commonly published databases in orthopaedic research have been the National Inpatient Sample, Medicare, National Surgical Quality Improvement Program, and those provided by PearlDiver. General advantages of most database studies include accessibility, affordability compared to prospective research studies, ease of use, large sample sizes, and the ability to identify trends and aggregate outcomes of multiple health care systems/providers. RESULTS: Disadvantages of most databases include their retrospective observational nature, limitations of procedural/billing coding, relatively short follow-up, limited ability to control for confounding variables, and lack of functional/patient-reported outcomes. CONCLUSION: Although this study is not all-encompassing, we hope it will serve as a starting point for those interested in conducting and critically reviewing lower extremity arthroplasty database studies.