I thought Aviva meant that she didn't go into how awful the accident was and the details of it very often.
In her version of it on the show, she briefly got back into the emotions and a more immediate memory of what happened. That didn't last very long and she quickly shifted into a more artificial mode of retelling. She usually talks about it as a certain type of narrative, which isn't that moving. And by the time she said that she didn't talk about it with her friends, she was already back in as a self-dramatizing narrator. she likes to present the injury in a sort of blase way, like 'oh I had an accident when I was a child... " and just shock people a little by how casual she is about the artificial leg. She can blow it off, and surreptitiously watch them suppress a certain horror or discomfort. Oor in the alternative sometimes she plays it up as a melodramatic scenario, as she started to-- but she probably doesn't go back into the memory itself, which she did for a few moments on the show.
With memories like that, you can talk about them til you're blue in the face without really talking about them, which is what Aviva usually does. But the moments that are genuine are very rare.