Turnkey=Survival

Turnkey=Survival

By providing more know-how, implant manufacturers can ensure their position in the supply chain.

Mark Crawford
Contributing Writer

Manufacturers and suppliers need to be quick on their feet to work in the implant business—the landscape is ever-changing, including increased regulatory scrutiny (metal-on-metal in hip implants, for example) and smaller, more complex implants that utilize more challenging designs and materials. Because of market changes, more OEMs are turning to just-in-time manufacturing and delivery, so big batch orders are down.

There also is the constant pressure to control and even reduce costs—which means that contract manufacturers need get involved in the earliest stages of development to contribute their insights regarding manufacturability of the design—what can be changed to make it easier to manufacture more quickly, and at less cost, without compromising quality?

One way orthopedic OEMs are controlling costs is by reducing their supply chains so they only deal with preferred vendors that can take on more services, from prototyping through production. Many OEMs still prefer to manufacture products in-house when it makes sense economically, especially when they have their own in-house foundries, manufacturing resources and expertise for hips and knees (smaller companies are much more likely to outsource manufacturing production).

Small-joint implants follow similar trends based on machine availability and in-house expertise. Even if they do have in-house resources, sometimes OEMs will outsource if they are building implants from materials that require special knowledge and equipment, such as ceramics or polyetheretherketone (PEEK).

“The big orthopedic companies do a lot of their knees and hips in-house since the capital investment is high, often due to the castings involved as well as secondary machining/polishing that is expensive and sensitive to achieve,” said Josh Sprague, vice president for Hoosier Inc., a Corona, Calif.-based manufacturer of metal and plastic parts for the orthopedic implant market.

“Hips and knees also have a mix of different materials such as ultra-high molecular weight polyethylene, titanium, and cobalt-chrome, not to mention the coating technologies, whereby the majority of spine implants, screws, plates and rods, are titanium or stainless steel and are easier to outsource,” added Brian McLaughlin, business development manager for Farm Design Inc., a full-service product development company headquartered in Hollis, N.H., with an office at the Global Cardiovascular Innovation Center at the Cleveland Clinic in Ohio.

Turnkey Is in High Demand

OEMs increasingly are focused on building relationships with turnkey partners—contract manufacturers and suppliers that can support various elements of their product life cycles. When OEMs outsource, they tend to outsource the complete implant—preferably to the fewest number of vendors as possible, which streamlines accountability, improves quality, lowers costs, and increases speed to market.

Turnkey suppliers must, however, have the right equipment and necessary talent to do the job. Some companies are investing in 8-, 10-, and even 12-axis machines to meet customer demands. Finite element analysis software allows engineering teams to quickly identify where the greatest stress/failure points will be for new implant designs, allowing them to make adjustments to increase longevity. Direct metal laser sintering and medical injection molding processes also are getting more attention from contract manufacturers.

Most machine shops use CNC Swiss-style lathe to perform thread whirling. During whirling the work piece rotates slowly while the tool rotates at high speed in the same direction. The thread pitch dictates the tool rotation rate and the bar feed rate. The helix angle (up to 25 degrees) is set by the angle of the cutter ring relative to the work piece.

New, more aggressive thread designs are a challenge for traditional machining.

“OEMs are always looking to maximize pull out strength in the bone/implant interface and minimize proximal migration and cross-threading within the locking cap mechanism,” said Joe Eisenbart, sales engineer for ASTRO Medical Devices in Mentor, Ohio, a contract manufacturer for spinal implants and small bone fixation.

Double-lead and triple-lead threads are becoming the norm in pedicle screw design—a double-lead screw will advance into bone twice the depth of a single lead thread with a single rotation of the driver; triple-lead threads will advance three times the depth.

“When you consider the quantity of pedicle screws that are employed in a scoliosis correction for curvature of the spine, this can translate to a significant savings in operating room time, which is big money,” he added.

Some thread designs, however, exceed the maximum degrees of inclination that can be achieved with Swiss machining.

“One of our roles when we work with OEM engineers is guiding manufacturability and keeping costs down,” adds Peter Randall, vice president of sales for Holmed Corporation, a surgical instrument designer and manufacturer in South Easton, Mass. “There are some new thread whirling tools that can cut threads in one-tenth the time of conventional machining. Although it costs about $12,000 to $15,000, once the technology is set up and running you can recover that cost quickly through faster and higher production, which of course customers like to see.”

OEMs prefer to give production work to turnkey suppliers.

“Staying on the leading edge has been a good thing for Hoosier and the other dominant contract manufacturers because the OEMs recognize this and provide us with more opportunities,” said Sprague. “However, good prices alone don’t cut it anymore. We have made investments in high-speed multi-axis machines that make parts in one operation complete, as opposed to typical 5-axis machining centers that make parts in two operations or more, plus have load time issues. We’ve also added automated deburring chambers to speed throughput after parts have made it past the machine finish line. Aside from capital equipment, we’ve also invested heavily in continuous improvement, our lean team, and we try to foster a creative atmosphere to find new innovative ways of manufacturing.”

The majority of OEMs outsource the manufacturing process for the entire implant family. Component-only outsourcing happens from some of the bigger players that have in-house manufacturing when they are overloaded or require a manufacturing process that doesn’t fit their core competency. Because of the quality control required, the majority of outsourcing for implantable devices remains in the United States and awarded to U.S. Food and Drug Administration (FDA)-registered and ISO 13485-certified shops.

“We’ve seen a major increase in quality and validation requirements from many of our OEMs over the past couple of years, which has changed the way our quality system operates,” Sprague said. “It’s no longer good enough to just have quality certifications; companies must also be industry-leading shops that lead not just by price, but also technology and quality infrastructure, while being both validation- and continuous improvement program-driven.”

Other implant products, such as spine, are easier to outsource because the control of the material is straightforward; these OEMs also are reluctant to invest in the equipment required for these implants that could be out of date six months from now, as the designs and market change.

“Shops like Hoosier and our strong competitors have a diverse equipment list that supports the changing market demands, but we also have a diverse customer base and can replace work on machines that used to be only spine,” continued Sprague. “This is why our capital investments are easier to justify for what could be a short-term (one to two years) life for a product, whereas OEMs might treat this investment differently, knowing that if the market demand changed their equipment could be left collecting dust.”

Metal on Metal: A Vanishing Act?

No orthopedic product has shown a greater swing in market demand than metal-on-metal hip replacement systems, thanks in part to the recall of DePuy’s ASR hip system in August 2010. On May 6, the FDA ordered 21 manufacturers of metal-on-metal (MoM) hip replacement systems to conduct postmarket surveillance studies, citing concerns for potential problems such as loosening, adverse local tissue reactions, and increased metal ion concentrations in the blood.

Data from published literature, as well as reports submitted to the FDA, indicate high blood concentrations of the metals used in the implants. Although this is troublesome, the FDA has stated that so far the data is insufficient to conclusively link increased metal ion concentrations of cobalt and chromium to rates of adverse events, including serious health conditions such as impaired kidney function and cancer.

The hip manufacturers have 30 days to file an outline of their plans with FDA, followed by collecting data on the frequency of implant failure, along with patient information such as blood samples that assess metallic ion levels. This order by the FDA is expected to further cool sales of MoM hip replacement systems. (Editor’s note: Please see “Metal-on-Metal Musings” in this year’s March/April issue of Orthopedic Design & Technology for more information about this subject.)

Delamination of the bone-in-growth coating on implants also could present a similar problem, according to Shane Collins, managing director for Directed Manufacturing Inc., a rapid manufacturing company in Pflugerville, Texas, that specializes in direct metal laser sintering.

“Although I am not aware of any plasma spray coatings or other types of surface treatment failing, it is possible,” he indicated. “However, by utilizing the additive manufacturing process, implant designers can eliminate the possibility of coating failure by using an engineered surface porosity, where the bone in-growth cellular reticulation is designed into the computer-aided design (CAD) model of the implant and built up in the additive manufacturing process, along with the structural part of the implant.”

Collins noted it virtually is impossible for the engineered surface porosity to become detached. Implant designers also have full control over reticulation size, shape, and depth. By controlling the cell structure with CAD, they can design a repeated, random, or even multimodal reticulation where the porosity changes depending on location or depth.

“The implant designer has control over how much osseointegration occurs and where it occurs,” said Collins. “Engineered surface porosity using additive manufacturing has been demonstrated on a number of different alloys, including Ti 6-4 and F75. There are several hip manufacturers in Italy using this process and the FDA has recently approved an additively manufactured device in the U.S. This should pave the way for more use of ESP for both knees and hips.”

C5 Medical Werks, a manufacturer of advanced ceramic components based in Grand Junction, Colo., recently has developed and launched a new high-strength biocompatible ceramic (alumina matrix composite) material for use in femoral head and acetabular cup devices, as well as femoral knee devices. According to the company, it provides high strength and high fracture resistance in combination with low wear characteristics, making it a good material for total hip replacement systems and next-generation knee and femoral resurfacing devices.

“In industry-standard femoral head burst tests, we are typically seeing values of greater than two times when compared to the FDA guidance figures,” reported Steve Hughes, orthopedic product manager for C5 Medical Werks. “For the patient, this greatly reduces the risk of failure in-vivo, without compromising biological and tribological performance.”

The inherent high strength and fracture toughness of this new material allows design teams more flexibility in exploring new concepts for knee and femoral resurfacing surgeries. “Ceramic is gaining in popularity over metal because of its mechanical strength, toughness, hardness, and fatigue properties,” added Andrew Nield, C5’s director of sales and marketing.
“More companies are also interested in using ceramic for resurfacing heads instead of metal—one of the big advantages with ceramic is that it creates fewer particles, and those that are produced are smaller in size and bioinert.”

More Advanced Materials

Contract manufacturers are getting more requests from OEMs to work with new polymers, carbon fiber, and other materials that exhibit radiolucent characteristics. The purpose is to give the orthopedic surgeon the ability to not dismantle a surgical site in order to take an X-ray, an option in the operating room that rapidly is growing in popularity.

“The challenge with these materials remains in the tooling and fixturing, as proper cutting tools are quite expensive,” said David Cabral, president of Five Star Companies in New Bedford, Mass., a manufacturer of general and orthopedic instruments. “Also, due to the high material costs, the cutting must be accurate and repeatable. We continue to work with our tooling suppliers to identify the best materials for speed, feed, and surface finish in order to reduce cycle times and eliminate excessive hand finishing.”

Invibio has created a porous PEEK material that could be an excellent substrate for enhanced bone growth. Although the greatest interest by OEMs so far in this material has been for the spine market, it easily could expand into other areas, such as knees and hips.

“For example, the current concern with metal-on-metal joints has highlighted the affect of imperfect clinical implantations, patient populations, wear debris, and metal ions,” said Marcus Jarman-Smith, technology leader for Invibio Inc. in West Conshohocken, Pa. “This means that these types of additional questions are now becoming pertinent for all new material candidates in this application, including biomaterials like PEEK.”

Fortunately, PEEK polymers have a long history of implantation (dating back to 1999) and successful use in regulatory approved devices. In May 2008, the U.S. Food and Drug Administration approved Invibio’s PEEK Vertebral Body Replacement System, a one-piece device to be used in the thoracolumbar spine to replace a collapsed, damaged, or unstable vertebral body during tumor or trauma management procedures. The system provides imaging visibility and allows for bone growth/fusion visualization and follow-up, as well as implant positioning checks.

“Although perceived as expensive, the material itself is only about two percent of the total cost of the device, and focusing on reducing these costs may not be the most impactful means of slashing the bottom line,” said Jarman-Smith. “As the demands on biomaterials have increased, their sophistication has also increased. This often also means that processing has moved further away from standard techniques and can sometimes be challenging for traditional vendors that are not familiar with the current state of the art.
Conversely, if a vendor is skilled in a particular material such as PEEK, then outsourcing can be beneficial and actually lower risk.”

Antimicrobial Coatings

One area of development that will have an impact on implants in the near future is antimicrobial coatings.

“This technology is somewhat of a buzz word in the industry right now because of the growing concerns around hospital-borne infections and their associated costs,” said McLaughlin. “But there is definitely merit in having a slightly more costly implant with a technology like this that could, in effect, prevent a six-figure issue for the hospital.”

The concept of an antimicrobial coating has existed for decades. Silver is well-known as an antibacterial agent and most antimicrobial technologies today rely on silver, at least in part. Several key drivers—recent changes in healthcare coverage, increasing bacteria resistance to antibiotics, and pressures on the healthcare system to be more cost-effective—have led to increased interest in preventing hospital infections, including the utilization of antibacterial coatings on implantable or inserted devices.

“Infections and other complications in hospitals are major issues, not only for hospitals, but insurance companies, device companies, and policy makers,” said Jonathan Brown, CEO for Axena Technologies Inc., a company in Providence, R.I., that has developed an antibacterial coating for medical devices to combat healthcare-associated infections.

Although hospitals have the most to gain by using this technology (reduced expenditures, improved quality of care), implant manufacturers also want to be part of this market.

“OEMs are definitely interested in coating technologies,” said Brown. “The use of a coating can greatly increase the value of a product. Although right now OEMs are seeking much lower volumes, there are some supplementary manufacturing technologies we can use to make smaller orders more viable.”

Brown indicated there are significant differences between various antimicrobial technologies and how they work.

“It’s often more than just laying down a material on a surface,” he said. “Many coatings have unique intellectual property surrounding their application. Our company has focused on creating a technology that facilitates standard manufacturing methods, where others have developed their own manufacturing as a result of a unique process. The majority of technologies have fairly complicated processes resulting in multiple patents, controlled processes and equipment. For most companies, owning the manufacturing is key to capturing the share of market value.”

Semprus BioSciences in Cambridge, Mass., is a venture-backed biomedical company spun out of the Massachusetts Institute of Technology about four years ago. The company is focused on developing technologies that will help eliminate more than 50,000 annual U.S. deaths and $11 billion in costs associated with complications that arise when medical devices are implanted in the body. Its research and development has now attracted the attention of the U.S. Department of Defense, which recently gave the firm $1 million to find ways to reduce infections and thrombus associated with orthopedic implants used to treat soldiers injured with high-impact wounds on the battlefield.

The company’s fundamental breakthrough is a novel surface modification that can be applied to devices implanted in the body (such as vascular access catheters, heart valves, artificial hips and knees, and breast implants), reducing platelet and microbial adherence after exposure to blood for multiple months. Instead of using a “big burst” of a drug coating at the beginning of the device’s lifespan(which is quickly depleted, leaving the device “at risk” for infection and blood clots)—the device is coated with a long-lasting, covalently bonded, non-leaching technology that keeps bacteria, fungus, platelets, and blood proteins from attaching to the surface of the device.

“Our goal is to help greatly reduce the ‘three Cs’ that are associated with medical devices—complications, costs, and complexities,” commented Semprus BioSciences chief technology officer Christopher Loose. “The adaptability of these unique biomaterials to diverse substrates such as polyurethane, silicone, and titanium creates broad opportunities for enabling next-generation products with improved clinical benefits across the medical device spectrum.”