Derby’s Got Legs, He Knows How to Use Them

There’s just something about the holidays and man’s best friend that brings out the best in people. [Tara Anderson], Director of CJP Product Management at 3D Systems, fostered a husky mix named Derby.  Derby was born with a congenital defect: his forelegs were underdeveloped with no paws.  This precluded the poor fellow from running around and doing all of the things dogs love to do.  [Tara] had fitted him with a wheel cart, but she still felt that Derby deserved more mobility and freedom.  Deciding that 3D-printed prosthetics was the answer, she turned to her colleagues and collaborated with Derrick Campana, a certified Animal Orthotist, to create a new set of forelegs for Derby.

The design is different from typical leg prosthetics; Tara felt that the typical “running man” design would not work for a dog, since they’d just sink right into the ground. Instead, the “loop” design was used, allowing for more playful canine antics. They were constructed using MultiJet Printing on the 3DS’ ProJet 5500X.  MultiJet Printing enabled the prosthetics to be printed with firm and soft parts, both needed for comfort and durability.

The first set they designed is lower, to help ease the dog into using the prosthetics and strengthening his muscles.  As he grows more accustomed to his newfound mobility, newer ones will be printed that will gradually increase in height.  Derby has taken a shine to his new legs, happily gallivanting around and in some cases outrunning his new owners!

This is a very neat variation on prosthetics; we are impressed with the novel design and efficacy. We would love to see this MultiJet concept explored in the Maker community with open-source platforms and materials, as well as more unconventional designs made possible by 3D-printing. We never get tired of seeing the many ways people have already created amazing prosthetics for men, women, and children. No matter your personal opinion on 3D Systems, you can’t deny that Derby is having a blast with his awesome gams.

If you are interested in following his story, Derby has a Facebook page.  You can also check out the Peace and Paws dog rescue that saved Derby from euthanization.

21 thoughts on “Derby’s Got Legs, He Knows How to Use Them

  1. Love this story, but I was thinking, shouldn’t the pups front legs be a bit taller? Seems like he doesn’t walk/run on the level. The look on his face in the videos is amazing though!

    1. Yeah, here is how it should have went down: Legs affixed to dog. “Oh, shit, those legs are WAY to short for this dog”. Guy scales them up in Maya and reprints them. “Wow, that was a big improvement! Now we can make a video where this dog won’t be criminally hunched forward.”

    2. I think they wanted to ease him into it; since he’s never been able to use his forelegs and deltoids like this before, it would have been too drastic for him and could cause injury to those muscles. It wouldn’t surprise me if they have him on level ones within a year.

      I’m amazed at the resilience animals can have. I currently own a parakeet (along with 2 other birds and cats) that I found with a crushed foot in a pet store cage. I told them I’d buy it if they saved him; long story short, he lived, is missing some toes, but climbs, perches, walks, and flies like a champ. He also freestyles the Super Mario Bros. theme when he’s happy :)

    3. In the video Tara quickly mentions the height. It’s because Derby is used to being low to the ground, so that it isn’t such a huge change. I also think it helps mobility and balance having them lower to the ground. Imagine standing on really tall stilts vs short stilts. Not to mention there’s a shorter distance to the ground so if Derby stacks it it won’t do as much damage. I think the prosthetics would need to be widened at the base if they were to be made taller.

    4. In the video they talk about how the first set of prosthetics were intentionally left short to allow the dog to get used to them.

      I recently watched a program on TV that showed a dog with a similar deformity, and similar prosthetics. In that case they also started low and gradually worked the dog into taller prosthetic legs.

  2. Wow, that is amazing, hope they do give the dog “longer” legs as he gets as he gets used to using, once the muscles in the forelimbs adjust to walking more natural stance would be better for his back. Oh yea, and what a cute little son of a bitch (yea, I said it! :)

  3. Longer prosthetics exert greater leverage on the dog’s stubby legs. Most joints in people (it’s the only model I can practice with) depend on making sure there’s an alignment between the bones and the load to be carried. The difficulty for this prosthetic is that there isn’t a muscular connection to make sure the prosthetic is aligned to keep it aligned with the leg. On the other hand, there is a large adaptability in the brain to cope with such disconnects, so I would not rule it out. This is where cart solutions can shine, though they limit mobility over uneven terrain, like stairs.

    1. Thanks, that’s along the line of thoughts I had. Although I love the love those people put in this project, I know from experience with handicapped animals that it’s a lot harder for them to make GOOD use of prosthesis, because they don’t hold themselves back while exercising. It takes time to build up muscle and cartilage to cope with the (considerable!) additional weight and the drain on the shoulder joints MAY (but does not need to) lead to pain and lameness.
      Not trying to be over-critically here, but the pace at which modern videos on such projects are cut and edited make the audience believe it’s a matter of days or weeks. It’s not. I have seen fully healthy dogs getting worn out by the wrong type of “sport” from to high expectations by their owners. And this one here has an even harder task to cope with than “just sports”.

      Good luck!

      P.S. To turn this into a bit more of a positive comment: The work done here could and should be transferred to animals that loose limbs or have them shortened at a higher age, with fully developed muscle-, cartilage- and bone-structures, they could benefit a lot from it.

      1. Had a good chat about this this morning with the SO. For me, one of the greatest things about the new “at home manufacturing” tools is how much it can reduce the cost and turn-around time of iterating, especially for one-offs like this. Come up with a design and do it up in CAD, run it through conversion software, and hit “print”. Couple hours later, you’ve got a prototype that you can try out. Find out that the curvature is wrong, or that it’s too heavy, or whatever? Well, make the design changes tomorrow morning and have another prototype ready to go tomorrow afternoon.

        1. @vonskippy Everyone who fabricated something before “3d hype zoinks OMG printers”, did so without imagining fabricating with 3d printers. Its called clay/ styrofoam carving or machining. Then you make a mold and inject or cast the mold. It is faster to make a pepakura object and lay up composite on it, and then you have a tougher product.

    1. Given that she’s employee at the company, I bet it went more like this:

      – Hey, I’ve adopted a dog with stumpy legs. I work at a 3D printing company. I wonder if there’s something we could do to help my little buddy out
      – Hey boss, do you mind if we spend a weekend fooling around trying to make prosthetic legs for my dog?
      – Boss: Go for it!

      – Hey boss, check this out!
      – Boss: Woah! Let’s put that on youtube! It’ll be good marketing, and a good demo of the way 3d printing can change lives!

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