The use of open reduction and internal fixation, by choice, is vindicated in selected fractures of the shafts of the tibia and femur, and in certain compound fractures of these bones. In this study, good results were found to be much more dependent upon the way the materials for internal fixation were used than upon their composition. Fixation rigid enough to make possible a maintenance of physiological function throughout healing most nearly accomplished the primary aim of all fracture therapy, —to restore the patient to his usual activities as soon as possible and in a condition as nearly normal as possible.