Sir,
vitamin D deficiency is a common finding now a days seen in Orthopedic practice. It's chiefly related to under-exposure to sunlight (which obviously has other side-effects). First of all, I would like you not to worry about the condition.
In practice we try to find out the cause for this deficiency by other biochemical investigations. Like
thyroid profile, parathyroid assay, mineral assay etc.
Considering your other parameters within normal limit, your treatment should start with oral supplement of Vitamin D.
I would suggest you to take Cholecalciferol (vitamin D3) tablet of 60000 IU weekly for 8 weeks and continue this as a single monthly dose for the next 10 months. (Total of 18 tablets in one year)
Along with this, you can take
Calcium + Calcitriol preparation for 3 months at least provided you have a normal renal profile.
Next Steps
Repeat
vitamin D estimation after 3 months to see any improvement in the level.