The Cavs said that they wanted to take a look at Embiid's post op records and film, but I haven't heard anything further about this. One would think we would be hearing something about this, good or bad, even if they are just rumors.
I'm sure they'll get some helpful info soon if they haven't already, but it's a tough call when it comes to these type of injuries. If I remember correctly, Z had multiple surgeries fail before having pins placed in his foot, and fortunately for him that treatment saved his career. Yao had pins placed in his foot only to have it ruin his career.
If you consider that stress fractures are prone to reoccur given the very nature of the term - thin cracks that are caused/inflamed by pressure - coupled with the fact that there are now multiple screws in his foot, there's no guarantee his surgery will be a success. I'm sure he's receiving world-class care, but if the screws aren't placed perfectly, if the bone doesn't re-grow and heal properly, if he manages to apply too much pressure too soon and re-aggravate the injury - there's a major problem going forward. Being 7'1 and having developed a stress fracture in your back a few months prior is not a good sign no matter how you slice it; regardless of how fluid of an athlete he is, he'll always be more prone to injury than the average person due to his size/length.
Typically, this type of surgery is a "what else can we do" measure rather than the norm. I'm not a doctor obviously, but I've had re-occuring stress fractures in my foot and I have several screws placed throughout my leg; from everything I've learned and read over the years for my own benefit, in addition to my curiosity in Embiid's situation, if the stress fracture wasn't serious, there were no need for the pins - he'd have a cast/brace and be told to keep off it for a couple of months. It's possible that stress fractures on 7 footers are treated with the upmost caution and the go-to option for these scenario's nowadays is always heal-via-pins, and it's possible that professional athletes undergo different procedures - I have no idea.
He'll be asked to keep off of his foot for 6-8 weeks either way. His healing progress will be evaluated throughout and following that time-span, and he'll continue to be monitored for months after he steps back on the floor in case the healing process didn't go as planned.
Odds are the surgery will go well if he's not prone to these type of injuries, but based on recent history, it's hard not to wonder if he is. That will be the game-changer, and I'm not sure it's something our med staff will be able to confidently predict. Most surgeries are successful, but the navicular bone in particular is prone to re-injury given it's location in the foot.
We'll see on draft day. Someone's going to take a gamble on him, but the cause for concern is legitimate no matter what the post-op records show.