The purpose of this study was to compare the number and types of extremity injuries treated at civilian trauma centers (CIV CENs) versus military treatment facilities (MTFs) participating in the Major Extremity Trauma Research Consortium (METRC) and to investigate the potential benefits of a clinical research network that includes both civilian trauma centers and MTFs. Two analyses were performed. First, registry data collected on all surgically treated fractures at four core MTFs and 21 CIV CENs over one year were compared. Second, actual numbers and distribution of patients by type of injury enrolled in three METRC studies were compared. While MTFs demonstrated higher percentages of severe injuries including open fractures, traumatic amputations, vascular injuries, contamination, and injuries with bone, muscle, and skin loss when compared to CIV CENS, the CIV CENs treated a substantially higher number and, more importantly, enrolled patients in almost all categories. Comparison of service members to civilians was challenged by several differences between the two patient populations including mechanism of injury, the medical care environment, and confounding factors such as age, social setting and co-morbidities. Despite these limitations, in times without active military conflict, clinical trials will likely rely on civilian trauma centers for patient enrollment; only when numbers are pooled across a large number of centers can requisite sample sizes be met. These data demonstrate the benefits of maintaining a military-civilian partnership to address the major gaps in research defined by the Military.