You might remember Derby, a dog who was born with a congenital deformity but last year received a 3D-printed prostheses that enabled him to run for the first time. Well, it's onward and upward for Derby and his carers, who have now crafted an upgraded set of custom prostheses allowing him to walk proudly with a straight back and even sit like a healthy dog.

Derby was born with very small forelegs and no front paws. His condition landed him in the hands of a New Hampshire-based dog rescue group called Peace and Paws, and eventually in the home of Tara Anderson. As it turned out, Anderson was an employee at 3D printing company 3D Systems, who quickly got to work using the firm's technology to carve out a solution.

This resulted in a set of prostheses consisting of attachment cups, rubber treads and rigid spokes, allowing Derby to run across all surfaces for the first time ever, albeit while very low to the ground. Not content with this, Anderson set about making new and improved prostheses that would allow Derby to go about his daily activities in a more comfortable fashion.

After sifting through many new designs of varying sizes, Anderson arrived at an iteration she likens to the human knee, in that it had just the right amount of give and take. She then crafted the new prostheses using selective laser sintering and fitted it to Derby's front legs, where he seemed to take them in his stride.

His new prostheses allow him to sit like a healthy dog and walk at his proper height, both of which he's never been able to do.

You can see Derby take his new prostheses for a spin in the video below.

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