BACKGROUND: Intramedullary nails provide no clear outcomes benefit in the majority of patients with intertrochanteric hip fracture, yet their use in the United States continues to increase. Non-patient factors that are associated with intramedullary nail use among Medicare patients have not been examined. The goal of this study was to identify the surgeon and hospital characteristics that were associated with the use of intramedullary nails compared with plate-and-screw devices among elderly Medicare patients with intertrochanteric hip fractures. METHODS: Medicare beneficiaries who were sixty-five years of age or older and underwent inpatient surgery to treat an intertrochanteric femoral fracture with use of an intramedullary nail or a plate-and-screw device were identified from the United States Medicare files for 2000 to 2002. Surgeon and hospital characteristics from the Medicare provider enrollment files were merged with the claims. Generalized linear mixed models with fixed and random effects modeled the association between surgeon and hospital factors and intramedullary nail use (compared with plate and screws), controlling for patient age, sex, and race; subtrochanteric fracture; Charlson comorbidity score; nursing home residence; and Medicaid-administered assistance. The adjusted odds ratios of receiving an intramedullary nail by year, surgeon, and hospital factors are reported. RESULTS: There were 192,365 claims for surgery to treat an intertrochanteric hip fracture that met the inclusion criteria and matched with surgeon and hospital information. There were 15,091 surgeons who performed intertrochanteric hip fracture surgeries in Medicare patients in 3480 hospitals between March 1, 2000, and December 31, 2002. The surgeon factors associated with intramedullary nail use include younger surgeon age (less than forty-five years old), an osteopathy degree, and operating at more than one hospital. The hospital factors associated with intramedullary nail use include a higher volume of intertrochanteric hip fracture surgeries, teaching hospital status, and having resident assistance during surgery. Surgeon factors improved the model fit more than hospital factors. CONCLUSIONS: The use of intramedullary nails was strongly associated with early-career surgeons and surgeon training programs. Our findings suggest that orthopaedic faculty at teaching hospitals and younger surgeons may be selecting orthopaedic implants on the basis of factors other than clinical outcomes evidence. We expect that intramedullary nail use will continue to increase as long as new surgeons are preferentially trained in intramedullary nailing procedures and surgeon reimbursement remains insulated from the treating hospital's burden of their choices for higher cost devices under the Medicare payment system.