Not 100% on this but I suspect some screws may be removed and a few may remain.. I know a couple folks who have had them left in after surgery, a lot of it may depend on their palcement and potential to re-aggravate the affected area.
His galloping days are over, but ya never know, he is young yet and may heal well enough that he may be able to lope around. He and the jockey did a good job of stopping when the injury occurred, this could have been worse were a rupture of skin or vessel to have happened..
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YES, SIR!
I really appreciate your concern for this animal!