Hi.
I've gone through your query and I can understand your 
anxiety. 
From the mentioned features like growth retardation, flared ribs & bowed legs in the history & the age group is paediatric (children), the condition can be 
RICKETS. 
Most common condition resulting from vitamin D deficiency in childrens would be rickets & adults is 
osteomalacia. 
If treatment is started in the right timings, the underlying vitamin D defect & other manifestations & deformities can be corrected. 
I Suggest you to, 
- have a word with the 
pediatrician to decided the dosage of vitamin D supplements. It can be low dose taken on Daily basis or high doses can be taken monthly or annual injections. 
- Additional calcium and phosphate supplements are also needed. 
- If your child is having 
bone deformity such as bowed legs or curvature of the spine, then along with the supplements, a brace or surgery is needed to correct it at the earliest. 
Hope I have answered your query. Let me know if I can assist you further. Take care. 
Regards, 
Dr. Yogapriya V, General and family physician.