Pup Tries Out New 3-D-Printed Paws "He was so happy,” owner says of dog's reaction to prosthetic paws and legs.

 -- One lucky dog is getting his stride back after being fitted with custom 3-D printed paws and legs.

Derby, a mutt believed to be mostly husky, was born without fully formed front legs. Instead, the dog had small “elbows” that left him pitched forwards as he tried to run and play with other dogs.

“He was scooting around on these nubs and chest,” said Melissa Hannon, who rescued Derby through her organization, Peace and Paws.

After taking in Derby from his original owners in Alabama, Hannon placed the pup with a foster owner, Tara Anderson, a director of product management at a company focused on developing 3-D products called 3-D systems.

From the first day that Hannon matched Derby with Anderson, she hoped they could figure out a way to get Derby fully on his feet.

“I think it was a vision,” Hannon said of the plan to create 3-D printed prosthetic legs for Derby. “No one knew if it would work or if it would take.”

As Anderson cared for Derby, she also started to work with people at her company to design prosthetics for Derby.

“We start him off very low so it wouldn’t be too drastic,” Anderson said of Derby’s first model on the 3D Systems website.

This summer, Derby was matched with his permanent owners, Sherry and Dom Portanova in Harrisburg, Pennsylvania. The couple said Derby could get around using a wheeled cart, but because it replaced his front legs it was hard for him to move around or interact with other dogs.

When Derby was given his first prosthetic caps, they were little more than “caps” to cover and protect his “elbows” as he scooted around.

“He took to those immediately,” Sherry Portanova told ABC News. “They have cushion inside. That meant he could go run on driveway and concrete.”

Anderson kept working with engineers at 3D Systems to fine tune the prosthetic limbs. One model looked like “peg legs” according to Portanova, and didn’t quite work when Derby tried to run around.

However the next model, Anderson designed -- a long looping prosthetic -- seemed to be just right for the energetic Derby.

As soon as Derby tried them on, Portanova said the dog just took off.

“The first time he was put on them and he took off running, he was so happy,” she said in a video for 3D Systems. “I was absolutely amazed at how well he did.”

Now, the dog runs every day with the couple, Portanova told ABC News. She hopes Derby's story encourages owners to adopt disabled pets.

"He’s such a good dog and he lives a full life," she said. "He’s very special. Everybody who sees him just loves him."