With the demographic changes in the world, especially a growing elderly population, the clinical need for better-performing implants and improved osseointegration is increasing rapidly. “This translates to an increased commercial focus as the orthopedic industry designs new devices for implant treatments,” said Ulf Brogren, chief commercial officer for Promimic, a provider of nanoengineered bioactive surface treatments for implants with headquarters in Gothenburg, Sweden, and processing operations in Warsaw, Ind. “In this important work, surface treatments have a crucial role to play for improved clinical outcomes.”

In the orthopedic field, “surface modifications and coatings are pivotal in enhancing the functionality and longevity of implants,” added Francesco Bucciotti, head of global business and business development at Lincotek Medical, a global solution provider for medical device manufacturers (MDMs). 

A significant research focus is improving osseointegration—the bonding between bone and implant—by utilizing materials such as hydroxyapatite coatings, and titanium and its alloy Ti6Al4V. Advanced methods such as plasma spraying, physical vapor deposition, and chemical vapor deposition ensure these materials are optimally integrated. Implant manufacturers have a special interest in coatings that address multiple performance aspects simultaneously, such as wear resistance and antibacterial properties, which may aid faster patient recoveries and reduced infection risks.

“The exploration of such technologies reflects the strong, ongoing demand for innovative surface treatments that can offer distinct advantages in an increasingly consolidated and competitive market,” said Bucciotti. 

Another driver of surface enhancements is the rapidly expanding minimally invasive device market. “Most of these devices rely on surface modifications to improve delivery and navigation, while also enabling combination benefits, such as anti-infection properties or drug-delivery capabilities,” said Joe Anderson, marketing manager for Minneapolis, Minn.-based Harland Medical Systems, a global provider of medical coating technologies.

Aesthetics and coloration are also key considerations in surface treatments—for example, different anodized colors make it easier for surgeons to identify tools and instruments in the operating room. Anodization can also be done on 3D-printed titanium porous structures, delivering all the key anodization properties and leaving no residues, thereby preserving the integrity of interconnected porous structures in 3D-printed implants. 

“We have very high requirements on the topographic properties of such implant surfaces, but also on the visual side,” said Michael Striebe, global process and sales expert, medical and aerospace, for Rösler Oberflächentechnik GmbH Germany/Rosler Metal Finishing in Battle Creek, Mich., which provides surface finishing solutions for mass finishing, shot blasting, and AM solutions. “Some surgeons want special surface effects like very high gloss shine on femoral knee implants.Others prefer a matte finish to reduce glare in the operating room.”

“Ultimately, the need for coatings and surface treatments in the medical device industry is critical for the end result—improved patient outcomes—whether the need is adding fatigue strength, lubricity, osseointegration, or is purely cosmetic,” said Kathy Siri, sales manager for Warsaw, Ind.-based Danco Medical, a provider of surface treatments and related services to MDMs and their manufacturing partners. 

Applications and Trends

Applications for surface treatments continue to expand. For example, HA^nano Surface treatment, a Promimic technology that Danco Medical offers through its joint venture Nano Processing, improves ossseointegration of orthopedic and dental implants and even has soft-tissue applications, such as bioactive sutures that create a more tissue-friendly interface, thereby improving clinical outcomes. “This has been updated in our Masterfile with the FDA to make it easier for customers to get regulatory approvals and reach the market faster,” said Brogren.

Orthopedic device companies are looking for new antibacterial solutions. The need for infection management is driving advancements in both preventative and therapeutic solutions, such as biofilm-resistant materials. Nanometric silver particles can now be deposited throughout additively manufactured (AM) materials, providing effective antimicrobial properties over time without altering the structure’s integrity. Due to their nanoscale size and shape, these particles penetrate bacterial membranes directly, killing a wide range of pathogens. Antimicrobial coatings can also limit the growth of troublesome microorganisms beyond the operating room—for example, when applied to non-surgical equipment and surfaces, bed rails, and trays. 

Increased regulatory scrutiny on particulate generation of medical devices has resulted in more focus on low-particulate coating solutions. “Also, as invasive technologies become smaller and travel greater distances in the body, reducing friction has become critical to offset reduced column strength, while also supporting extended travel and improving trackability,” said Anderson.

Due to health issues (local toxicity, inflammation, and metal hypersensitivity) related to the shedding of ions from cobalt-chromium (Co-Cr) alloys commonly used in implants, the coatings industry is keen on developing new coatings as alternative solutions—for example, multilayer ceramic materials that improve wear resistance and significantly reduce ion release. These advanced coatings support bone integration and minimize allergic responses through encapsulation techniques that isolate Co-Cr surfaces—thus enhancing implant biocompatibility.

Anodization is a standard electrochemical process in manufacturing that coats machined metal parts with an oxide surface layer, making them stronger and providing an attractive finish. Aluminum, titanium, and magnesium are common metals that are anodized. Once only applied to machined parts, anodizing can now be applied to AM products as well.

For example, Danco Medical’s 3DGrowth-Color anodization process can be used on intricate AM components, achieving uniform coloration even in complex lattice structures. The anodization process penetrates porous titanium structures thoroughly, while still ensuring contact materials are properly removed through an internal processing step.

“These advancements demonstrate that while AM surfaces require specialized solutions, innovations in wet chemistry and anodization enable MDMs to overcome these challenges, optimizing the surface modifications that support both the functionality and aesthetic requirements for advanced medical devices,” said Tim Zentz, general manager at Danco Medical. 

“We developed our color titanium anodize process for additive product to support the evolving needs of MDMs and contract manufacturers for their titanium products,” said Siri. “Additive manufacturing techniques are growing fast in the orthopedic arena and post-processing can be a key bottleneck when using AM as an industrial process. In particular, color titanium anodization on AM porous parts plays a very important role from the cosmetic and identification perspective.”

What MDMs Want

For surface modifications and coatings, MDMs consistently prioritize solutions that are qualified, validated, and compliant with regulatory standards as essential requirements. “Ensuring coatings meet these rigorous benchmarks supports not only high performance, but also smooth market approval across multiple regions,” said Bucciotti.

One of the most popular surface treatments is electropolishing, a critical finishing process for the orthopedic industry that improves surface finish and overall product performance. Electropolishing boosts manufacturing efficiency, enhances product durability, makes parts easier to clean and sterilize, and increases corrosion resistance. Tiny (±0.0002 inches) surface defects and contaminants left behind by the machining process can be easily eliminated with microscopic precision, leaving critical metal parts free of microburrs, microcracks, and other defects, while enhancing durability and corrosion resistance. With the exception of precious metals, almost any metal alloy can be electropolished.

Another standard process is etching.

With the rapid growth of AM, Multi-Etch, a Clarkdale, Ariz.-based provider of etching services for the medical industry, uses its own etching process to remove unfused particles left on printed titanium parts. The process is also critical for prepping titanium for anodizing, plating, and welding. “Multi-Etch is easier to operate safely compared to hydrofluoric acid and easier to control the amount of material removed so as to maintain critical margins,” said CFO Antonio Giordano. “Since Multi-Etch is not as aggressive as hydrofluoric acid, it excels in removing amounts of titanium as thin as fractions of a micron. This allows for precise removal of material that is difficult to achieve with the blunt action of hydrofluoric acid.”

The company maintains a database of etch rates on its website for customers to reference when enhancing surface properties for titanium and other metals, including shape memory alloys.

A prominent area of MDM interest is the integration of 3D-printed porous structures with advanced surface treatments, such as nanostructured calcium phosphates. Nano calcium phosphate treatment enhances 3D-printed titanium or other implant surfaces by providing a bioactive layer that significantly improves osseointegration. The porosity of the 3D-printed structure supports bone ingrowth and mechanical stability, while the nano calcium phosphate coating accelerates the biological bonding process. “Together, these features meet the industry’s growing demand for implants that promote faster recovery, better stability, and long-term durability, making nano calcium phosphate coating-modified 3D surfaces an increasingly sought-after solution in the orthopedic field,” said Bucciotti.

MDMs are always looking for ways to reduce process times by finding surface treatments and coatings that streamline manufacturing without compromising quality or performance. One way is to use nondestructive testing methods, which are faster and less expensive than destructive methods. For example, Harland Medical Systems relies on a non-destructive inspection method for testing its Lubricent BrightView hydrophilic coating. Traditionally, because these ultra-thin, low-friction coatings are nearly transparent, “manufacturers had to rely on destructive staining tests to verify coverage,” said Anderson. “Our technology eliminates that challenge by viewing coatings under black light, enabling quick, reliable confirmation of coating presence on every device, without damaging the product.”

Ongoing Innovation

Since rapid launches of new products in the orthopedic industry create an increasingly competitive environment, MDMs need fast and reliable finishing solutions to maintain high product quality and throughput. This requires moving away from manual processes to embrace digital technologies, including Internet of Things, automation, and AI. 

“Very often we still see companies using manual deburring and finishing processes,” said Striebe. “However, we have more customers looking into automated finishing processes to gain higher quality levels, as well as improved reliability and repeatability. This leads to moving away from manual finishing to automation like our new Surf Finishing technology, part of our suite of tools called Rösler Smart Solutions.”

Surf Finishing is ideal for high-quality, delicate, and complex work pieces. It provides up to 40-fold higher processing intensity than vibratory systems. The combinable process steps (for example, pre-grinding, fine grinding, and polishing) can be automated and integrated into production cells.

“This new technology allows us to finish titanium femur implants within 20 minutes,” said Striebe. “No touch-up is necessary—combined with electropolishing, we are able to produce a perfect surface finish without micro-scratching. We are able to reduce the processing steps from three to two. Also, we are able to process internal surface areas from acetabular cups in a vibro finishing machine without manual work.”

The Lincotek R&D team prioritizes innovation with a clear focus on addressing clinical challenges, particularly through the development of solutions aimed at reducing infection risk, enhancing wear resistance, and minimizing ion release. “For example,” said Bucciotti, “Lincotek has designed and supports Bonepore through a Master File submitted to the FDA. This porous structure created via 3D-printed titanium is optimized to enhance implant integration and supported by rigorous documentation.” 

Visual inspection for quality control continues to improve through advances in computer vision, using AI and machine learning algorithms to detect aesthetic defects such as scratches on metals or stains and black spots on hydroxyapatite. For process control, it is essential that extensive data is collected in a systematic and correct manner, which is sometimes difficult to accomplish because real-world data usually comes from different sources (production machines, external sensors, or measuring systems).

“As with all AI systems, however, it is essential to develop the algorithms without creating unintentional biases, which would create false alarms, or conversely, miss important signals,” said Bucciotti. “Algorithm development requires a solid and well-specified data science and machine learning base.” 

When MDMs first approach Nanovis, a Columbia City, Ind.-based producer of nano surface technologies for orthopedic, spinal, and dental implants, about surface technologies, they usually inquire first about osseointegration. In most cases, the company’s nanoVIS Ti product fits well with their project needs. Backed by extensive data and validated by its FDA Nanotechnology Designation, nanoVIS Ti is an engineered, permanent nanotube surface technology applicable to any commercially pure titanium or titanium alloy implant that meaningfully accelerates osseointegration. “It also reduces bacterial colonization, increases vascularization, and improves inflammatory response,” said Kreigh Williams, director of research and development for Nanovis.

Promimic has developed a state-of-the-art nanotechnology that mimics nature, making it possible to create a unique bioactive surface on any implant. HA^nano Surface is a 20-nanometer-thin implant surface treatment composed of crystalline hydroxyapatite (HA) particles, which have the same shape, composition, and structure as HA found in human bone. HA^nano Surface has proven to accelerate bone growth in over 30 in-vivo and in-vitro studies. Faster and stronger osseointegration has been demonstrated through biomechanical, histomorphological, and biological evaluations, in combination with over 2.3  million clinical implantations to date.

Moving Forward

As medical technology advances, coatings will continue to play a foundational role in pushing those innovations forward. “The demand for high-performing solutions continues to grow, prompting research and development that brings better outcomes to patients and healthcare providers alike,” stated David Gasparik, director of engineering at Wheeling, Ill.-based Orion Industries, a provider of functional industrial coatings and applications to the medical device industry.¹

Engineered materials continue to advance. Titanium and ceramic materials are playing larger roles in the implant field. HA^nano Surface can now be applied to nearly all implantable materials, including machined titanium, additive titanium, cobalt-chrome, stainless steel, polyether ether ketone (PEEK), and additive PEEK, creating a super-hydrophilic surface that improves osseointegration of the implant. 

Medical engineers are intent on designing next-generation materials and implants that reduce friction and wear, improve biocompatibility, enhance performance, and maintain their functionality and accuracy over time. These improvements result in minimized particle release, better articulation, and longer life of components. With these advances, it is possible to “manufacture and deliver a medical implant, together with the needed specific surgery tooling, in four to six weeks,” said Striebe.

There is growing interest in diamond-like carbon (DLC) materials. DLC is a thin, hard coating made of carbon with properties similar to natural diamond. The durability of the DLC coating is achieved by making use of interlayers between the implant substrate (Ti6Al4V or Co-Cr or stainless steel), making DLC one of the most advanced surface treatments available in medical technology.

Lincotek’s proprietary DLC coating is specifically engineered for long-term implantation on both Co-Cr-based and Ti6Al4V-based orthopedic implants. “This coating technology allows us to fully encapsulate both on the articulating and bone in-growth region with an almost defect-free DLC layer to minimize corrosion/ion release in Co-Cr, enhance articulation on Ti6A surfaces, and allow bone in-growth in the coated porous region” said Mukesh Kumar, technology and R&D director for Lincotek Medical.

Innovation is on display as new surface treatments and coatings are announced. For example, a team of Massachusetts Institute of Technology engineers has developed a method for eliminating the accumulation of scar tissue around implantable devices. Medical devices that are implanted in the body usually trigger an immune response that leads to the growth of scar tissue. Known as fibrosis, this scarring can impair implant function, sometimes to the point of requiring surgical removal. The MIT approach uses adhesive hydrogel coatings that bind the device to the tissue, which prevents the immune system from attacking it.²

“This should help with the many scenarios in which people want to interface with foreign or manmade material in the body, like implantable devices, drug depots, or cell depots,” said Hyunwoo Yuk, a member of the research team and chief technology officer at SanaHeal, a bioadhesive technology firm in Cambridge, Mass.²

In another discovery, scientists at the University of British Columbia have invented a coating that vastly reduces the risk of thrombosis, or clot formation, after implant surgery, which can result in stroke and heart attack. Catheters coated with the new material showed a significant reduction in clotting on the implant or device surface. The new material, designed to mimic the natural behavior of blood vessels, “could be a transformative step in the development of safer medical devices,” said Jayachandran Kizhakkedathu, a professor of pathology and laboratory medicine at UBC.³

Looking ahead, surface nanotechnologies will advance to become a must-have standard of care for improved healing and patient outcomes. 

Williams believes that next-generation solutions cannot focus on osseointegration alone. They must also help fight the bacterial battle, improve vascularization, and support the right immune response. “These are the pillars we see as essential to advancing healing and delivering meaningful clinical outcomes,” he said. “With this approach, we are not just innovating for today, we are also shaping the future of surface science in orthopedics. We are excited about what is ahead and confident these innovations will continue to raise the bar for how surface technologies drive patient healing.”

Common Misconceptions 
MDMs often believe that surface modifications and coatings for cementless implants cannot achieve robust osseointegration and infection resistance without compromising the porous structure of 3D-printed components. This is not true—for example, “Lincotek’s proprietary TiGrowth technology provides a plasma spray coating that promotes both bone ingrowth and ongrowth on titanium,” said Francesco Bucciotti, Lincotek Medical.
For low-friction coatings, many MDMs underestimate how effective these coatings can be at enabling minimally invasive devices to navigate complex vasculature, or they assume it is better to select a naturally low-friction substrate rather than specify a coating. “In reality, “said Joe Anderson, Harland Medical Systems, “applying a well-engineered coating often delivers superior performance and consistency, while coating low-friction substrates can potentially be more challenging.” 
MDMs are often surprised by the compatibility between nanoVIS Ti and 3D printing. As AM becomes increasingly prevalent in orthopedics, it introduces complex geometries and lattice structures specifically designed to improve fixation. Engineers sometimes assume that applying nanotechnology to hidden or intricate geometries is not feasible and will occlude porosity. “However, because it is bath-based, nanoVIS Ti can be applied uniformly to a product, even within the most intricate lattice frameworks,” said Kreigh Williams, Nanovis.

References

1. tinyurl.com/odt251141
2. tinyurl.com/odt251142
3. tinyurl.com/odt251143

Mark Crawford is a full-time freelance business and marketing/communications writer based in Corrales, N.M. His clients range from startups to global manufacturing leaders. He has written for MPO and ODT magazines for more than 15 years and is the author of five books.