I'm sorry that your dogs our fighting
I know how you feel - two of our larger dogs used to fight frequently. It is so scary.
Eventually we tried a pet whisperer... it was free so I figured "why not". At that point I was willing to try anything, regardless of what I believed. Our case was a little different, as it didn't appear to be a jealousy issue but more or less an alpha dog thing. Lucy was the only child until Sammie came along. It seemed to help. There has only been one fight since then, it was back in May and there was a cause behind it. When before there would be no cause and it would start in a blink of an eye.
Maybe it has something to do with the surgery? Maybe Kikki feels she needs to protect you when you are weak? I'm no expert on animal behavior, and before you sell Kikki, perhaps see an dog behavioral specialist?