This study analysed the effects of reaming and intramedullary nailing and thoracic injury related to development of ARDS and multi-organ failure in multiply injured patients. Sixty patients were entered into a retrospective follow-up study. Twenty-one patients with thoracic injury and femoral shaft fracture, treated by intramedullary nailing, were compared with 17 patients with a femoral shaft fracture without thoracic injury, and with 22 patients without femoral shaft fracture but with major thoracic injury. The incidence of ARDS, multiple organ failure (MOF) and the mortality rate in the groups was analysed, using chi 2 and Fisher exact tests. No significant differences in age, sex and ISS existed between the groups. There were no statistically significant differences with regard to the incidence of developing ARDS (P > 0.5), MOF (P > 0.5) and mortality rate (P > 0.2) after injury. The results of this study suggest that reaming of the femoral shaft as part of an intramedullary nailing procedure is not a major cause in developing ARDS and MOF in patients with femoral shaft fractures and thoracic injury. Conventional intramedullary nailing can be considered as a safe procedure in femoral shaft fractures in multiply injured patients, as well as in the presence of major thoracic injury.