Spicoli, how did you know it's a hairline fracture, only x-rays can tell, if not done, well we are just guessing.

A thorough medical history and physical exam by a physician provides enough information to determine if further testing is necessary.

What will be the harm in getting x-ray? It could be a Linear Fracture instead. Linear fracture runs parallel to the bone's axis or direction of the bone's shaft.

Your Tibia needs rest to provide healing instead of supporting heavy load of your body, casting can also be done or just plain rest.