Geographic Variability in Medicare Hospital Reimbursement for Primary Total Hip and Knee Arthroplasty Episodes of Care From 2013 to 2023.

Background: Medicare is the largest payer of total hip arthroplasty (THA) and total knee arthroplasty (TKA) in the United States, yet reimbursement has shifted substantially in the past decade. We described and compared state- and region-level trends in Medicare inpatient reimbursement for primary THA/TKA from 2013 to 2023. Methods: This study retrospectively analyzed the Medicare Inpatient Hospitals by Provider and Service database for diagnostic-related group 470 (major hip/knee replacement without major complication or comorbidity) from 2013 to 2023. Extracted fields were hospital-submitted charges and Medicare facility payments, inflation adjusted to 2023 US dollars. State means were discharge-volume-weighted to reflect the average beneficiary; states were aggregated to US Census regions (Northeast, Midwest, South, and West). Regional differences were compared, and longitudinal trends were estimated using linear mixed-effects models, including year, region, and their interaction. Results: In total, 3,724,353 primary THA/TKA discharges were billed to Medicare. Annual inpatient volume fell 84.1% (451,603 to 71,939). Inflation-adjusted reimbursement per discharge declined from $15,808 to $13,696 (-$2113; -13.4%), whereas charges rose from $71,469 to $85,675 (+$14,206; +19.9%). No state experienced an inflation-adjusted increase. Regional declines ranged from -19.1% (Midwest) to -10.1% (West). Mixed-effects modeling showed an overall decline of approximately -$285 per discharge per year ( Conclusions: Inflation-adjusted Medicare inpatient reimbursement for THA/TKA decreased nationwide with consistent but heterogeneous declines across states and regions. The steepest reductions occurred in the Midwest and the smallest in the West, underscoring persistent geographic variability with implications for access to arthroplasty care and sustainable payment models.