A small cannulated bone screw is provided having an optimized combination of strength, cannula size and thread depth. Cannulated screws are inserted where the neck of femur has been fractured and where there is a good chance that it will heal if held in place by internal fixation. Cancellous cannulated screws come in small and large sizes.A cannulated screw for cancellous bone should be self-tapping and self-cutting.
https://www.siiora.org/cannulated-screws/