I should add that surgery is good at some things but not very...

I should add that surgery is good at some things but not very effective at fixing tendon tears. ATI is far better. In my case a bit of tendon was taken during the surgery and the plan was for tenocytes to be produced from it.
I was given the option of leaving that on hold (the biopsy can be stored but not the tenocytes) after surgery to see how things worked out but I decided to give the go ahead and had the implantation a few weeks later when the tenocytes were available. My thinking was that as the SL tears were still there, and I had paid OCC up front, I wanted to get everything done. I did cop 2 lots of physio, one after the surgery and one for the implantation.
My case is unusual in that ATI was an adjunct to surgery but there must be cases where that is the right approach if you can find the right surgeon.