A short nail ends where it ends — and anything below its tip is unprotected bone. When the fracture extends into the subtrochanteric region, when the canal is wide or the bone is metabolically weak, the long nail earns its place by carrying the fixation past the isthmus and giving the whole femoral shaft a load-sharing internal splint.
The cephalomedullary principle is shared with the short nail: a lag element crosses the neck into the femoral head and slides as the fracture settles, while the nail body bears the bending loads of the shaft. The long version adds distal locking and full-length protection against fracture propagation in fragile bone. Fracture classification, entry point and implant length remain decisions for the operating surgeon.
