Dear Doctor, My mother is 47 yrs of age, . About a fortnight ago, she suddenly developed swelling in her right leg (knee downwards), accompanied with pain & discomfort while walking. This continues till date. X-ray was done which showed no abnormality, except for superficial swelling, and diffuse osteoporosis, normal for her age. The swelling now also appears to be in both her legs. One of the doctors has advised that it could be due to Vitamin D deficiency, and has advised that 1 dose of Arachitol 6L injection (intramuscular) could be beneficial. My question is are there any possible side effects of this injection that we should be aware of, and your advise about this treatment.