All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad  is His slave and Messenger.
  is His slave and Messenger. 
If the ears are protruding beyond the usual condition in a way that they are considered as a deformity, like bat ears, then this is a (physical) defect, so it is permissible to treat them with cosmetic surgery provided the operation does not lead to another harm.
For more benefit, please refer to fataawa 83177, 87848 and 190645.
Allaah Knows best.