Suggest Treatment For Tibia Spiral Fracture In My Leg

hii doc im 14 and i had a tibia spiral fracture to my left leg first the doctors said that i have to undergo a surgery but i ended up with a long leg cast now what my problem i cant bend my left leg knee it is very tight and tomorrow im going for physio do i need to do any excersises plzz sugest sum excersises for me and if needed sum tablets