Not good?
He has chronic knee problems, potentially in both knees, but definitely his left. He will have to be carefully managed the rest of his career.
However, I highly doubt he retires. He is under contract for the next three seasons and has a $69 million player option for '28-29. I don't think he will leave $248 million on the table, no matter how bad his knees are. Insurance could cover the contract but he would need to be ruled medically unfit to play and that doesn't happen often.
The bigger question is what is the 76ers future? Embiid looks like being a liability at $248 million over 3 years, Paul George has been bad this year and is owed $162 million over the next 3 years and Maxey has $168 million remaining over four years. While Maxey is very good, he can't carry the team on his own especially with $168 million tied up in those three guys in '27-28 when the other two may not even be useful players!