4 yr old boy buckle break . broken ulna and radius in growth plate clean break no shifting what are chances of having to get pins put in?

Likely just casting: If it is displaced, likel he will only need casting for a few weeks. 4 year old often heals very well and so not likely to need pinning/surgery. My son had a buckle fracture when he was almost 2 and needed casting for about 4 wks. He healed completely. Consult doc. Good luck.

Minimal: Assuming minimal to no displacement of the fracture fragments (aka buckle fracture), typically these fractures heal within 4-6 weeks in this age group.