A third patient is "still in early rehabilitation, and a longer period of convalescence and rehabilitation is to be expected," a spokeswoman for the University Clinic of Würzburg told AFP.
Overall, the condition of all four had "greatly improved," she said, adding that she could not give further details due to confidentiality reasons.
All four victims were members of the same family who were travelling on a Bavarian train when they were caught in an axe rampage by a refugee who had claimed to be from Afghanistan.
Terror group Isis later claimed the attack, in which a total of five people were injured. It was one of two attacks claimed by Isis in Bavaria within six days in July, the other being a bomb attack on the town of Ansbach which killed the attacker and wounded 15 others.
The teenage assailant was shot dead by police.