There are two risk factors for testicular torsion. The first is that there's probably a genetic component in some patients because family history of men having testicular torsion increases a subsequent generation male risk of having torsion. The second is a previous history of torsion. If there's been an episode of torsion in the past, the person is prone to torsion in the future. That's why when one side is affected, typically surgery will secure the other side to prevent from twisting in the future because both sides are felt to be at risk.
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