As it is mentioned in many studies that one major advantage of the backward sliding mechanism of lag screw is controlled compression of fracture with weight bearing which helps in healing of fracture.

There were no significant differences in fracture alignment, hip screw position, tip-apex distance, union rate, time to healing or complication rate.

The utility model belongs to a medical bone wall reamer which is suitable for reaming a bone wall before extracting a left screw after the healing of all kinds of fracture damage.