Each of these routinely used treatments has potential advantages and disadvantages.
Resting the arm in plaster cast for up to 4 weeks, to allow it to heal by itself:
The benefit is avoiding surgery. However, the main risk of this is that healing is less reliable, which may lead to an unstable elbow causing pain, stiffness and/or clunking and may rarely need more complex surgery later on.
Surgery to fix the bone, usually with a screw and a splint or cast for up to 4 weeks:
The benefit is more reliable healing. There are however risks of surgery, which include those associated with an anaesthetic (low risk), wound healing problems, pain or stiffness, injury to nerves supplying the fingers and breakage of the bone or metal. There is commonly the need for a second surgery to remove the screw once the bone has healed.
Dan, SCIENCE study doctor