Advice please? my 9yr old son has a closed fracture of his thumb. will ortho cast it or leave it splinted?

Variable: Some types of fractures are more like dents in a tubular structure like a soda can, these need no cast but might benefit from a splint or cast for control of discomfort. Some closed fractures will cross through a growth plate at that age and might need surgery to pin the pieces in proper position, followed by casting.Your doc will decide.