National Trends and Geographic Disparities in Hip and Knee Arthroplasties in Brazil During 2021-2024: A Descriptive Epidemiological Comparison of Public and Private Healthcare Systems

Background: Hip and knee arthroplasties are among the most commonly performed orthopedic procedures worldwide.However, there is a significant gap in the understanding of their epidemiology in Brazil, particularly regarding geographic variation, differences between healthcare systems, and demographic patterns.Methods: This descriptive observational epidemiological study analyzed national administrative data from both the public healthcare system (Unified Health System (SUS)) and the private healthcare sector.All hip and knee arthroplasties performed in Brazil between January 2021 and December 2024 were included.Data were evaluated according to age, sex, geographic distribution, procedure type, and underlying diagnosis, with comparisons between public and private systems.Results: A total of 322,611 arthroplasties were identified, including 207,670 hip and 114,941 knee procedures.The most affected age group was 70-79 years, with a predominance of female patients.Hip arthroplasties were more frequent overall.The distribution between public (48.09%) and private (51.91%) sectors was relatively balanced.Notable differences were observed between systems: hip arthroplasties predominated in the public sector, largely associated with fracture-related cases, whereas knee arthroplasties were more common in the private sector.Substantial geographic variability was identified across Brazilian states.Conclusions: Arthroplasty utilization in Brazil differs markedly between the public and private healthcare systems and across regions.Hip arthroplasty predominated overall, driven disproportionately by publicsector trauma cases, while the private sector showed a more balanced hip-knee distribution, a pattern that differs from high-income countries.These descriptive findings, which were not adjusted for age, sex, disease burden, or differences in population coverage between sectors, should be interpreted as observed utilization patterns rather than established evidence of access disparities.