How to treat a broken leg

If skin is broken, do not touch or put anything on  the wound.
You must avoid infection. If the wound is bleeding severely, try to stop the flow of blood by applying steady pressure to the affected area with sterile bandages or clean clothes.

Do not move the injured leg—you need to put a splint on  the wound to stabilize the injured area.

Find two stiff objects of the same length—wood, plastic, or folded cardboard—for the splints.

Put the splints above and below the injured area – under the leg (or on the side if moving the leg is too painful).

Tie the splints with string, rope, or belts—whatever is available.
Alternatively, use clothing torn into strips. Make sure the splint extends beyond the injured area.

Do not tie the splints too tightly; this may cut off the circulation of blood.
You should be able to slip a finger under the rope or fabric. If the splinted area becomes pale or white, loosen the ties.

 
Have the injured person lie flat on their back.
This helps blood continue to circulate and may prevent shock.