Are retinal detachments common after getting hit in the eye. how can this be fixed?

No: But it definitely happens. If you have floaters, flashes or change in vision, see an ophthalmologist asap.

Not common, fixable: Minor to moderate trauma to the eye rarely causes retinal tears and detachment. When it occurs, retinal reattachment surgery with vitrectomy or scleral buckle (types of surgery) can fix retinal detachments. When the trauma is severe, retinal detachments are more common, and the success rate decreases with increased severity of the trauma. It all starts with an exam by an eyemd.