The male animal, weighing around 200 kg, was voluntarily turned in by the family living in Phuc Tho District.
Now named Uno, it is among the first bears in Hanoi to be voluntarily handed over and sent to the Vietnam Bear Rescue Center in the northern Vinh Phuc Province, according to Animals Asia.
It was sedated, taken out of the cage and checked.
Rachel Sanki, veterinary surgeon at the Vietnam Bear Rescue Center, said Uno suffers from a curved spine, possibly due to arthritis, which prevents it from being able to lie down properly, she added.
It also has plaque on his teeth and bald patches from rubbing on iron bars.
The rescue was also aided by the Hanoi Forest Protection Department and the Dan Phuong District Forest Protection Department.
There are around 170 bears kept in farms, around 140 of them in Phuc Tho District.
Thus far Animals Asia has managed to rescue 220 moon bears and sun bears from several places around the country. Around 188 of them are being taken care of at the center.
Both species are classified as vulnerable by the International Union for Conservation of Nature.
Vietnam banned bile extraction in 2005, but farmers who owned bears prior to the ban were allowed to keep them.