Falling over and not able to get back up does not sound related to a wing injury. That sounds like something else.
Is she using the wing to try to stabilize herself like a crutch? That likely isn't a wing injury but a balance issue.
Birds with a wing injury may have a droopy wing, but they run around just fine. They simply can't fly or flap well.
We would need to know more information such as age, how suddenly this came on, any other appearance of illness.
It could be anything from vitamin deficiency, weakness due to severe anemia from worm overload (usually stop laying at that point), or illness such as Marek's or MS.
Again, we'd need to know more information.
LofMc