Interesting that the blocking is partial. I didn't know that. In discussion I've ever had about riding horses after nerving, it has been my [false] assumption that the heel and the whole foot was numb.
My vet's wife had a horse she rode in dressage for years after nerving for navicular. The precision of movement and soundness demonstrated in dressage tells me that it is quite possible for them to 'find their feet' and still have good sound movement. All the best to you and Winnie and your daughter.
They just numb the heel area, the horse is still aware where the foot is landing. This procedure is not without risks, though. The horse can get a nail in the frog and never know it so you have to be vigilant about checking their feet. Also, there is a risk of the cut nerve growing what they call "neuromas" and they also cause pain and can be a complication. I'm gonna have to take the risk, I got a hurtin' horse right now so I need to try anything that might work.
By the way, a neurectomy is a salvage procedure. Afterwards, this mare will only be worth the killer or broodmare price. I am keeping her as a broodmare, if I can keep her comfortable.
I wouldn't be dealing with this at all had I been smart enough to get Winnie a pre-purchase exam. I wouldn't have bought her after seeing the x-rays. I knew better than to trust anyone selling a horse but I was sick of looking and Winnie was nice and the seller seemed honest.