Billy you DO have issues in the SPINE. That's why you have drop foot! Your knees and ankles do NOT cause drop foot. Your spine causes that.
So ask your Neurosurgeon what his plan of action is going to be. You don't want drop foot to become permanent, right? Something in the spine is causing this.!!!
So ask for further tests or whatever needs to be done. This can't just be left "as is." Hugs, Lee