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Materials will play a crucial role in orthopedics as OEMs design smaller, more intricate parts and adopt new manufacturing techniques. As orthopedics advances, adopting additive manufacturing, robotics, minimally invasive surgery, etc., it’s likely that OEMs will leverage the primary materials in use today. What should OEMs consider when they think about marrying today’s materials with future orthopedic applications?
In April, BONEZONE hosted a webinar focused on discussing the ever-evolving trends, challenges and changing regulations associated with orthopedic device materials. The webinar was sponsored and led by Carpenter Technology’s Brent Marini, Medical Strategic Business Developer. The panelists included:
- Gaurav Lalwani, Ph.D., Medical Applications Development Engineer, Carpenter Technology
- Gordon Hunter, Ph.D., Principal Manager of Materials Science, Smith+Nephew
- Chuck Hansford, Director of Advanced Development Center of Excellence, Tecomet
- Dale Tempco, Industry Consultant
The panelists shared insight into what they’re seeing day and day out, specifically when it comes to developing products for robotic-utilized procedures and minimally invasive surgeries (MIS), as well as leveraging additive manufacturing.
Materials for MIS and Robotic Applications
With MIS and robotic surgery predicted to explode in growth over the next decade, Chuck Hansford of Tecomet stressed the need for companies to fully comprehend the end results of their goals, but also what role materials will play in order to achieve them.
“Products are getting smaller and smaller and tolerances are getting tighter and tighter,” Hansford said. “Looking at manufacturing methods to make these parts, your tooling has got to be small, right? The materials have to be able to yield to whatever sized tool that you can get in there to use. As we move forward, we need to understand the end result and whether technology can keep up with the need. It’s going to be the biggest issue that I see.”
Hansford stressed the need for companies to step outside of their usual methods and preferred material usage in order to accommodate the unique needs of MIS and robotic surgeries. He specifically cited plastics as a material that might not “hold up” to the rigidity of these complex and technologically sophisticated surgeries.
“The trend of robotics and minimally invasive surgeries is here to stay, and it’s growing,” said Dr. Gaurav Lalwani of Carpenter Technology. “With that, there’s going to be more and more focus on tight tolerance and instrumentation applications, and parts with very fine features and dimensions. From a materials perspective, the way we see that playing out is that in addition to elevated properties with respect to high yields and high activities, to be able to achieve these fine features there’s also a big shift in manufacturing methods. You see all the advancements and CNC, milling and machining. Now, that’s coming out with these next-generation systems with all the focus on industry 4.0 with lights-out manufacturing, with one operator trying to run the entire shop floor. I think it becomes very important for a material supplier like Carpenter to actually understand these trends and try and support them to the best of our ability.”
Dr. Lalwani mentioned that several of his customers in the robotics industry reported difficulties in machining small surgical tools.
“They would essentially run 40%, 50% scrap in some cases. So how do you come up with a solution to that?” he said. “We’ve been taking a good hard look at the production processes of these materials––the way we produce and treat them along with the metallurgical knowledge that we have with respect to all of the different alloys that we may have across different industries. We’re trying to learn from those areas and understand how we can apply something here to come up with a solution for this trend that is definitely going to stay and become more prominent as we move forward.”
Materials for Additive Manufacturing
The conversation then shifted to additive manufacturing. When asked why over 90% of FDA-cleared 3D-printed devices were made from either Grade 23 or Grade 5 titanium, the panel noted that the materials were uniquely suited for medical purposes.
“The materials lend themselves perfectly for the medical environment. I think the material of choice would be the Grade 23 because of the low oxygen content,” he said. “A lot of companies that I’ve dealt with have migrated to Grade 5 because of not being able to control the oxygen content through the development process of the additive machine. Oxygen tends to grow in that environment. Grade 23 would probably be the material of choice. In the medical environment, those are materials that have shown the best end result going through the additive process. But from an additive manufacturing standpoint, titanium is one of the hardest materials to actually grow in the process because of residual stress and some of the effects that happen during the welding process. But I will tell you that in the past 20 years, titanium has been the number one material used in my environment, and it’s only because of the quality of the product and the ability to grow and control.”
Dale Tempco has noted that the popularity of using titanium for additive manufacturing is due to the longevity and familiarity of using it in orthopedics. There are a number of “exotic alloys” available for additive manufacturing purposes, and while there are opportunities to use other materials, the orthopedic industry doesn’t rely on them because it’s risk averse.
“I think what you’re going to see, as trends evolve and the acceptance of additive manufacturing as a production option grows, is a bigger trend into different material applications,” Hansford said. “But that also is going to require the F42 committee to develop the ASTM standards around those materials. I think you could have a huge market today in 17-4 stainless steel instrumentation if there were a standard created to support that.”
Hansford went on to highlight various benefits of 17-4 stainless steel materials before presenting what he saw as a major obstacle keeping it and other materials from adoption by orthopedic technology companies.
“We’re so focused on what we’ve always done and how we’ve always done it,” he said. “And we forget to look at how we can improve it and move forward with the new technologies and materials.”
Adoption of New Materials
Multiple market forces have orthopedic manufacturers considering different materials, but few are developing new materials. In various points throughout the discussion, the panelists addressed why that is.
In talking about the reporting changes for cobalt chrome under the new EU Medical Device Regulation, Dr. Hunter of Smith+Nephew was asked whether new alloys could be developed for the orthopedic device market.
“It is hard to justify the introduction of a new material when the ones we have, including cobalt chrome moly, work so well already,” he said. “The cost of entry is very high. Unless there is a really strong driving force toward alternative alloys and alternative materials, it’s not going to happen in the current regulatory environment except in extraordinary circumstances.”
Dr. Hunter played a key role in Smith+Nephew’s development of Oxinium, an oxidized zirconium material, and noted the nearly-decade long timeline. While he didn’t foresee a sea change in the industry regarding alternative alloy materials, he predicted that biological solutions would be the driving force in the market over the coming decades.
In discussion, the panel highlighted the lack of volume as a significant challenge facing the creation of new materials in the orthopedic device industry. Industries like automotive and aerospace, where large amounts of materials are used, will see a faster evolution in materials.
Ultimately, the panelists said that it will take all portions of industry – device companies, contract manufacturers and materials suppliers – to work together to better understand how to advance materials science for future orthopedic applications.
