If a baby has a spiral fracture to the arm would it be visible on future x rays?

Possibly: Although the body's ability to heal & remodel a broken bone is amazing (especially in an infant) evidence of an old fracture may show on radiograph (x-ray) especially if the fracture fragments are not in perfect alignment. Thus the bone should be x-rayed, aligned, & cast/braced by orthopedic surgeon to prevent deformity or decreased function.