Double-hand transplant recipient eight-year-old Zion Harvey smiles during a news conference Tuesday, July 28, 2015, at The Children's Hospital of Philadelphia (CHOP) in Philadelphia. Surgeons said Harvey of Baltimore who lost his limbs to a serious infection, has become the youngest patient to receive a double-hand transplant. (AP Photo/Matt Rourke)

Surgeons in Philadelphia have performed a double-hand transplant on a boy believed to be the youngest patient to undergo the procedure.

Eight-year-old Zion Harvey's forearms are still heavily bandaged but his new hands were visible as he joined at a news conference Tuesday.

The was conducted earlier this month at The Children's Hospital of Philadelphia.

Zion thanked his family and doctors for helping him on a "bumpy road."

The boy is from the suburban Baltimore community of Owings Mills.

His hands and feet were amputated years ago because of an infection. But leg prosthetics let him become an active child, and he learned to eat, write and play video games even before the double-hand transplant.

He will spend several weeks in physical rehab before returning home.

THIS IS A BREAKING NEWS UPDATE. Check back soon for further information. AP's earlier story is below.

An 8-year-old Baltimore boy who lost his limbs to a serious infection has become the youngest patient to receive a double-hand transplant, surgeons said Tuesday.

Zion Harvey received the hands earlier this month at The Children's Hospital of Philadelphia, though doctors did not publicly disclose the 11-hour operation until now.

A 40-person medical team used steel plates and screws to attach the old and new bones. Surgeons then delicately reconnected arteries, veins, muscles, tendons and nerves.

Double-hand transplant recipient eight-year-old Zion Harvey smiles during a news conference Tuesday, July 28, 2015, at The Children's Hospital of Philadelphia (CHOP) in Philadelphia. Surgeons said Harvey of Baltimore who lost his limbs to a serious infection, has become the youngest patient to receive a double-hand transplant. (AP Photo/Matt Rourke)

Zion, a bright and precocious child, contracted an infection years ago that resulted in the amputation of his hands and feet. It also necessitated a , an organ he received from his mother.

Leg prosthetics have allowed Zion to be very active, including walking, running and jumping; he attends school and has learned to use his forearms to write, eat and play video games. Physicians hope his new hands will enable many more milestones, including his wish to throw a football.

Several adults in the U.S. have received double-hand or double-arm transplants in the past few years. Hospital officials in Philadelphia believe Zion is the youngest person to undergo a double-hand transplant, which requires a lifetime of immune-suppressing drugs to ensure the body doesn't reject the new limbs.

Zion has already been taking anti-rejection drugs because of his donated kidney, making him a good candidate for the , doctors said.

Doctors say Zion will spend several weeks in physical rehab at the hospital before returning home to Baltimore.

Details on the donor and the operation's cost were not immediately available.