Nails of various types, either round or square, have been used for internal fixation of intracapsular fractures of the neck of the femur with varying success. This type of treatment has been abandoned because it brought about partial and temporary fixation only. Since the fixation was only partial, immobilization by means of a plaster cast had to be superimposed on the open operation until repair was far enough advanced to stand the strain of function. Since early function is the most important principle in the treatment of any joint fracture, this type of treatment necessarily fell short of the ideal. The type of nail previously used brought about temporary fixation only. This was due to the fact that the nail was massive; it displaced so much bone that it actually created pressure necrosis surrounding it. Due to this necrosis, within a short time the nail became loose and ceased to