I know nothing about little ones with broken legs...but I would take her to an orthopedic doctor to be sure to do whatever will give her the best chance to heal properly, especially being so tiny. They have to be extra cautious, you'll want someone that does this type of surgery on little ones all the time, they really will know what's best, get a consult, maybe casting is the right thing for her...but don't wait any longer...do it now. Best wishes to your baby for a full and speedy recovery!!!
__________________ As Ever, Kathy 
Intruducing Bentley  Winston and Spencer: RIP My Sweet Angels |