The butterfly fragment in comminuted femoral shaft fracture may be movable following intramedullary nail treatment.

The gap among fracture fragments is an important factor which influences the healing of bone fracture, and it may be changeable during the early phase of bone healing. In this letter, we pointed out our view that the gap between the butterfly fragment, and the shaft in femoral shaft fractures can easily be changed, so it is hard to study the potential correlation between the size of the gap and fracture healing.