Looking the limited x rays it appears she has a non union which can be confirmed via further imaging if wanted.  I know she is only 14 but it needs to heal and get her length and alignment back.  I personally would excise the non union and compress with a circular frame and do bone callous distraction through the frame to regain the length you lose with the resection of non healthy bone.  

Good luck

o eliminate pseudarthrosis and restore the length of the limb is best with use of the Ilizarov method in Kurgan scientific center named after G. A. Ilizarov in Russia

looks most probably pseudoarthrosis, needs removal of implant,excision of pathological fragments,fixation with circular fixator, compression followed by distraction to achive the required length

I think that is could remove the implant, placed a nail locked  associated with graft and a month after a dose of 5 mg zoledronic acid IV.