At times like this management has to come into it. Is there any possible way to build a run or such on the furtherst point away from the fence line with the cows?
While your knee is being operated on also seriously try and find someone to take her.
Distance is the key to any fear or reactive training. They have to be aware but still able to be brought out of it or back to you with a treat or ball or whatever is their "thing".
I don't like the citronella collars because after a couple of sprays it remains on the dogs coat, kind of defeats the purpose, that's why I recommend either the puff of air or the electric, but not for fear. Fear or aggression problems are not solved by use of aggressive methods. And I use aggressive for want of a better word.
Would it pay to even move the hidden fence on the side with the cattle to keep her further away? Actually scrap that she barks in the house.
Have you tried a combination of training and medication?