@Pheebs52, that was an interesting conversation. I'm a writer, and a medical writer also (long story), so I could tell at our initial conversation that he was evaluating me--just as I was evaluating him. On Monday, he said he could tell I would do well with BTKR. And I pounced on that and asked, "How could you tell?" Because, like you, I'm inherently curious about such things.
He said it was because I was tough. Now, if you met me, you would not think that. I'm 60s, overweight (okay, officially obese), avoid exercise, and have a pretty soft life. I work from home. I'm a snowflake. A writer. My health is only good: I have diabetes, high blood pressure, and gastric reflux. I am, however, strong (very active youth and middle age, so heavy bones and lingering good muscle tone), curious (I told him I'd researched him, TKR, and recovery options), determined (he asked why I wasn't using a cane or in a wheelchair already with the degree of bone on bone in both knees), and was willing to work through pain (ditto). I'd remained active even with horrible knees. So he figured I was tough enough and determined enough to tough out a BTKR recovery.
He did say it's not for everyone. I didn't ask how he determined who he would dissuade from BTKR.
I went to him hoping for a BTKR. That entered into it also. I was mentally "there."