While many people believe that a fracture is a "hairline break," or a certain type of broken bone, this is not true. A fracture and a broken bone are the same thing!
Both of these words mean that the normal bone architecture has been disrupted. This does not imply a certain type of treatment, but in general, bones heal best when immobilized. Therefore treatment often involves casting of the broken bone (or fracture) and may require surgery to fix the bone into place (see O.R.I.F.).
For more information: Broken Bones