And I still don't think he refers to the MRI scan. I think he meant that procedure he took regarding putting something into the knee to help it heal (sorry, I can't quite remembered the whole thing). I read that last year when Jo injured his knee, the paper talked about Jo getting that procedure just like Gilles had earlier for his knee problem.
The only procedure I know of that Gilles ever mentionned is the infamous Zamar, a cryotherapy machine he had to wear around his leg. Jo and Gael used it too but it's nothing remotely close to a surgery.
Jo had some infiltration done for his knee, basically a blood injection, which is the risky "shock" treatment to avoid having to rest for months. Clearly, Gilles didn't choose that option.