What do you think is the most likely diagnosis?
This is a classical case of rickets.
Why is the growth plate widening seen in the case?
Rickets is primarily a mineralization defect, and excess of non-mineralized osteoid gets accumulated at growth plate, resulting in its widening.
Which other similar condition, may have widening of growth plate as well as widened anterior end of ribs (rosary)?
Scurvy (vitamin C defiicency) may present with similar findings.
Extensive osteoporosis, remodeling, cupping, fraying and bone age nearly less than 2 years.