I get a new knee tomorrow.

I don't know, I think you should have shopped around for a surgeon that draw a straight line. Funny how different yours is than mine - my scar is straight and just a bit under 7" long.
It's surprising how common this surgery is becoming. But I still think it's remarkable how they basically cut your leg in half and glue some new parts in to create a new knee. The prosthetic knee I got was developed a few years ago by my surgeon and his partner and mimics natural knee motion. Rather than just a hinged joint, I can actually swivel a bit on it just like a real knee.
Jokingly I told my kids to make sure they salvage it when I'm gone. Who knows what the value of titanium is going to be? They were not amused.