New LL Nail Design - Optimized

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Hello everyone, I’m an engineer and have personally undergone limb lengthening (LL). From my experience, I realized that the design of the nail plays a crucial role in the LL process — it not only affects recovery efficiency but also accounts for a significant portion of the total cost.

That’s why I’m developing a new nail design with the following criteria:

• Low cost, similar to solid nails, to make limb lengthening more accessible to a wider group of people.
• Fully mechanical operation, yet smooth and reliable like the Precice nail.
• Fully internal, eliminating the need for an external fixator.
• Made from common materials like stainless steel, but with strength comparable to Betz or Solid nails.

I hope my design can provide a practical and affordable option for the LL community without compromising on performance or safety.

Do you think a nail like this could actually exist? Please share your ideas and suggestions here!

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Quote from: Unknown on July 11, 2025, 06:46:43 AMIdeally a titanium nail that has more biocompability with the body, otherwise a good quality stainless steel that allows for nail reversal for times of non union to reverse lengthening. Not sure if possible with mechanical nail though.

Thank you! Titanium is definitely a great option. Grade 5 titanium has better hardness than many types of stainless steel. However, there are certain stainless steels that are even harder than Grade 5 titanium and are also more affordable. When prototyping, I plan to use several different alloy types to test their real-world strength and determine the most optimal material choice.

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The design of this nail is nearly complete. I'm currently preparing the necessary machining equipment to create the first prototype. After that, I plan to apply for a patent. Mass production may take some time, but I believe it won't take more than five years.
The pricing may depend on various factors such as initial investment costs, production volume, and more. However, I believe it will still be more affordable than current internal designs, even though it offers more advantages. During the first year of production, there will be several pricing incentives and discounts available.

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Quote from: Charizard on July 12, 2025, 03:18:47 PMHow it will do the lengthening? Twisting?

I believe the Twist design has already been patented.

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This nail operates with a completely new mechanism. You guys should also come up with a cool and impressive name for it.

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Quote from: Harry99 on July 12, 2025, 05:01:16 PMWhich country are you from, USA? My man

Man, I’m not American and I don’t live in the U.S. right now either. Why did you think that? Does my English sound American or something?

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Quote from: Harry99 on July 13, 2025, 05:49:05 AMYour writing skills and correct grammar make you sound better. As good countries have good engineers and u retired early, so it possible in USA with good salary.,

I’m from Vietnam. I stopped working from 2019. Salary there are quite low, though I did get some well-paid short-term project offers from European and American companies. In Vietnam, if you're really good at something, they often find a way to move you into a completely different field — basically forcing you to start over from scratch.

Thankfully, in 2018, I had the opportunity to leave Vietnam — specifically, I moved to Japan. Even though I didn’t speak much Japanese, I was fortunate enough to succeed outside of my main job. I did extremely well in software business and cryptocurrency, which made me financially independent — and I’ve been retired ever since. I didn’t know much Japanese, so I ended up going back to Vietnam — right around the time COVID started.

After COVID, I used the money I earned to invest in various fields, including the research and development of this nail design. I’m also planning to move to a developed country — possibly the U.S. — especially with Trump’s incentives for products manufactured in America. The things I’ve been investing in and researching are quite difficult to implement in Vietnam.

Of course, before I retired, my English was already decent. But now, after years of not using it regularly, I use chatbots to help correct my grammar so it’s easier for you all to read.

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Quote from: Body Builder on July 13, 2025, 08:37:29 PMWish you the best. We truly need a good nail who doesn't need a fortune to operate with. LL is ridiculously expensive, no other cosmetic surgery comes even close  and the nail cost play a huge role to that. I am not a fan of mechanic nails but if the lengthening mechanism is not something barbaric like albizzias and the price is good, why not.

A good name would have been something like "mechastrong" (from mechanic nail and strong built). If you like it I can give you the copyright in exchange of some free nails to do femurs 

Thank you for your copyright. The nails will be free for the first people undergoing limb lengthening with this type of nail.

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Quote from: Pan Island Expressway on July 14, 2025, 01:29:35 PMI had to learn all about these nails in engineering school and honestly, from a technical perspective I don't think there's need to reinvent the wheel as the current generation of intramedullar nails have pretty good function already.

What I think would make your nail stand out is cost. At the moment Precice is dominating the market. It'll be great if you can create a nail to give patients/surgeons another brand option that isn't something from Nuvasive. Don't forget that lengthening nails are used in many trauma/deformity cases too, and the cost right now is really bad. And many of these patients really need it to regain their quality of life.

Btw titanium is not used for hardness but rather biocompatability. You're not fixing a metal beam but a dynamic human bone which is constantly remodeling. If it's too hard bone may not grow due to stress shielding. Some degree of deformation is apparently good for bone growth.

I think that you are at the patenting stage. Do you have any plans for clinical trials? The whole approval process is usually the part that takes quite long.

I have no intention of creating this nail to compete with existing manufacturers. I am a limb lengthening patient myself, and my goal is to develop something that truly addresses the needs of other LL patients.

If you believe cost is the only advantage, I encourage you to revisit the engineering behind successive generations of SpaceX engines:


LL nails typically remain in the body for a limited period, so my primary focus has always been on the durability of the materials. Even SS420 stainless steel with titanium coating has been under consideration, Of course, whether it's made of titanium or stainless steel, the price will still be competitive. Everything will undergo rigorous validation — from simulation to real-world testing — before reaching the market.

I have not filed a patent application yet, but this is something I plan to complete within the year, prior to prototype development. My target is to bring the product to market within the next five years.

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Quote from: Pan Island Expressway on July 14, 2025, 02:45:00 PMI hope you realise that the moment you develop a medical device that fulfills the same goal as another device preexisting in market, you will be competing with the existing manufacturers. I hope you also realise that SpaceX does have cutting cost as a consideration when they design, it's just that space travel is inherently expensive so a certain high cost is expected and cannot be reasonably cut.

You will also need to do preclinical trials and an ethics review and then the actual clinical trials, phase 1, 2 and 3 which will take more than 5 years to market. Unless you are creating an undermarket unaccredited device that you sell in your backyard to shady "surgeons". Which maybe you are...I guess I shouldn't judge if your nail still helps people.


It seems to me that you might have some connection to a manufacturer. And yes, it’s possible that my innovation poses a threat to your interests. However, trying to prevent people in your own country from accessing something they deserve — simply because of that — isn’t the right thing to do.

I understand your frustration. I’ve been in your position at least twice myself. But I also believe that better things lie ahead for you. After all, we didn’t stick with Nokia phones forever, did we?

Thank you for sharing information about the procedures — I will look into the necessary regulations and legal steps required in each country.

Quote from: Pan Island Expressway on July 14, 2025, 02:45:00 PMSubmit his words to an AI detector. He is definitely using some kind of AI to write it. His writing style is very chat gpt sounding. But I do know many non native speakers use AI to translate, so it's not necessary a bad thing.

Quote from: nvafee on July 13, 2025, 10:05:24 AMBut now, after years of not using it regularly, I use chatbots to help correct my grammar so it’s easier for you all to read.