That injury destroyed him for mow. Thiem is in the same situation as Murray just cant get back to that elite level like he was. He lost 10+ games in a row and that cannot happen to a grand slam winner. Murray at least after injury won some matches and is doing the maximum at this moment. But Thiem finally got his wins
Not sure what was the problem with Thiem, but as far as I know, he did not have anything that serious. It is more of a case of lost form/confidence than actual physical handicap.