A Polish toddler found unconscious in freezing temperatures in November has left hospital after months of treatment that saved his life and restored limb functions.

Just weeks ago the toddler, Adam, was near death, with almost no heart beat and a body temperature of 12.7C.

Today he left the hospital, walking by his mother's side, his life saved by a string of professionals.

"We feel extremely lucky that we can go back home with our son, who is almost fully able-bodied again," said the boy's mother, identified only as Paulina.

Adam, aged two and a half, still needs rehabilitation at home, but his condition is "all that we were hoping for", said Janusz Skalski, a children's heart surgeon who oversaw bringing the boy back from deep hypothermia at the children's hospital in Krakow, southern Poland.

Adam "plays, frolics, runs, he can even be unruly", the doctor told reporters. "He behaves exactly the way he should behave."

He said Adam's ordeal did not affect his intellectual development.

At a news conference before leaving the hospital, Adam walked by himself - some movements a bit exaggerated - and played with small toys and a mobile phone, even though his fingers are still a little cramped.

Rehabilitation was needed to restore his ability to walk and hold objects that was lost when the freeze damaged his nerves.

Anna Swierczynska, the head of the rehabilitation team, said a lot of work was put into Adam's rehabilitation. The arduous exercises had to be done in the form of games and play to make the lively boy repeat them, she said.

Adam's heartbeat was one every 30 or more seconds when he was brought to the children's hospital on November 30.

A policeman found him, with almost no clothes on, lying unconscious by a creek. He apparently sneaked out at night from his grandmother's house in the village of Raclawice, near Krakow.