Upper extremity (UE) trauma -specifically, hand and wrist trauma -is a substantial public health issue representing a common presentation to the emergency department. [1][2][3][4][5][6][7] Injuries at different levels in the UE affect hand and wrist function and include wounds and vascular, nerve and musculoskeletal injuries. The frequency of these injuries is increasing secondary to population growth and aging and associated with rising health care costs for acute and ongoing care. 3 Large volumes of UE trauma have the potential to create a sizable impact on the health care system. Although existing data report the health system cost of acute trauma care for UE, [1][2][3]6 little is known about longitudinal health care costs.Longitudinal cost estimates of UE trauma provide evidence for hospital administrators, policy decision-makers and researchers assessing novel prevention strategies and care pathway models. The primary objective of this populationbased study was to determine the attributable long-term direct health care costs and utilization after UE trauma that required acute surgical intervention, with a specific emphasis on hand, wrist and UE peripheral nerve injuries. We employed an attributable cost methodology, which provides the most accurate representation of health care cost. 8,9 Further, we sought to identify key high-cost populations for targeted needs assessment and program development and the impact of patient-specific factors on health care utilization and cost.