How Evidence Transforms the Funding of Lower-Extremity Arthroplasty Implants in Chile: Costs and Clinical Variability Under the Diagnosis Related Groups System

OBJECTIVES: Lower extremity arthroplasties (LEA) have increased in frequency and complexity, reflecting technological advances and their growing viability as treatment options. The Diagnosis-Related Groups (DRG) system shows limitations in capturing their clinical and financial heterogeneity. This study assessed the balance between actual hospital costs and DRG reimbursements to evaluate sustainability METHOD: A descriptive observational study was conducted in 617 patients undergoing LEA at a traumatology specialized institution in Santiago, Chile, in 2023. Three clusters were defined based on age, diagnosis, DRG severity, length of stay (LOS), implant type, hospitalization costs, and DRG payments. Expenses were estimated using national health system records and implant dispatch records. RESULTS: The study population included 85.3% primary arthroplasties, 8.7% revisions, and 6.0% tumoral resections. Three clusters were identified: hip fractures in older adults (median LOS 9 days, mean cost $9936 United States Dollar [USD]); osteoarthritis with scheduled admissions (median LOS 2 days, mean cost $4544 USD); and bone tumors or complications (median LOS 10 days, mean cost $26 330 USD). Implant costs represented 48.1% of total expenses. A global financial deficit of 12.4% was observed, concentrated in cases of fractures, complications, and oncologic conditions. CONCLUSIONS: LEA showed negative margins under DRG-based funding. Evidence demonstrated how clinical and economic variability can drive funding reforms, leading Chile's National Health Fund to incorporate differentiated payments for primary, revision, and oncologic cases.