Is there a level of foot drop where it is safe to wear heels?

Not safe: Sorry, but a foot drop already means that your toes are touching the ground first before the rest of your foot. To wear high heels is accentuating that toe touch, and will greater predispose to tripping, falling and injuring yourself.

Intersting question: Because of extensor weakness in dropfoot one could wear a heeled shoe to accommodate the plantar flexion of the foot. The problem lies in the ability to swing through the dropfoot side in swing phase of gait. This could prove to be dangerous and a fall could easily occur. You would be better of with a fasionable AFO ankle foot orthosis that would prevent plantarflex of your foot and allow clear.

Foot drop: Foot drop is associated with l5, sciatic, or peroneal nerve injuries. The muscles intreated by these are the stabilizers of your ankle. The most unstable position of the ankle is the place you put yourself into wearing a high heel. Absolutely not safe!