01.24.07
Putting Orthopedic Devices to the Test
OEMs turn to contract testing partners to reduce risk and increase time to market.
Ursula Jones
Contributing Writer
Whether it’s business, research, sports—you name the endeavor—there’s very little reward without risk. Most people likely would consider that an axiom. Developing orthopedic devices is no exception to the rule. As increasingly complicated and innovative products are created, orthopedic companies take on enormous risks. One way to help mitigate a little of the risk is through rigorous testing and analysis. Done early on in the process, it can help maximize the odds for success.
Should an orthopedic company choose to partner with a contract testing firm, the earlier the testing company comes on board, the better the chances of achieving time and cost savings. “The sooner we get involved, the more we can impact the manufacturability and quality of the product,” said Bob Walden, manager of new business development for Incision Tech in Staunton, VA. “Proper testing leads to design choices that make sense in terms of higher performance, lower cost and products that provide better outcomes for patients.”
Medical device testing can involve a variety of processes and procedures. Photo courtesy of Nelson Laboratories. |
Not only can earlier involvement by the testing firm help with manufacturability and quality, but it also can speed the entire testing process. “If we’re brought into the picture early on in the R&D phase, we can help our clients outline their overall testing strategy,” explained Terry Langenderfer, global marketing director for Northwood, OH-based NAMSA. “We can often design an efficacy study to provide biocompatibility [safety] data as well.”
This process not only can save OEMs both time and money in reduced testing costs but also in opportunity costs by getting the product to market faster, industry experts said.
In an effort to get new products to market as quickly as possible, it’s tempting for some orthopedic companies to try to accelerate the testing and analysis phase; often, however, contract testing providers have to temper this sense of urgency. “The testing phase can be a challenge for new ventures—and even established companies, too—because sometimes the devices don’t hold up,” said John McCloy, president of Accutek Testing in Cincinnati, OH, a full-service fatigue and wear testing company.
Other challenges plague testing companies as well. For example, some OEMs will submit multiple iterations of products to their testing firm—particularly in the initial design phase—as a method of determining which material will work best. Comparative studies also may complement this search for the optimal material. While this strategy may not pay off for every project, there is some value in this approach: doing this can save valuable time if the first design or material doesn’t perform.
If the tests reveal a failure, it’s time to look more deeply at the results. Failure analysis is critical. “We use data acquisition to determine failure modes and to help clients that may need product development assistance,” McCloy said. “We’re not only able to test the device, but we’re also able to tell you why it failed.”
To do that, Accutek’s engineers will examine the grains of the device at a microscopic level. “There are a lot of problems that can be avoided if you do the proper evaluations,”
he added.
Efficacy Studies
As the orthopedic market matures, OEMs will require more testing to prove efficacy and superiority to other devices, especially as the Centers for Medicare and Medicaid Services (and other healthcare providers) require companies to prove their device is better than what’s currently on the market before granting reimbursement coverage.
Shown above and below are "ground sections" from resin (plastic) embedded blocks (samples). Photo courtesy of NAMSA. |
Langerderfer added, “If a new device is introduced that isn’t more effective than similar devices already on the market, or if the manufacturer wants to charge more for that product, there may be implications for the reimbursement strategy.”
Efficacy studies have other utility as well. One such use is putting a device through a functional test, which can prove claims about a device. “For example, we perform studies on bone-void fillers to see how well these materials stimulate bone formation,” Carraway said. “Any time device manufacturers make a claim, they have to be able to support thatwith some type of data.”
“We characterize a predicate device using these standard ASTM tests. Then we will test the new devices and compare them to the predicate devices,” he said. “We need to be able to demonstrate equivalence from a regulatory point of view.” (ASTM International—formerly known as the American Society for Testing and Materials [ASTM]—is one of the largest voluntary standards development organizations in the world for materials, products, systems and services.)
Because 510(k) devices typically don’t involve a new material and there are predicate devices already cleared by the FDA, biocompatibility tests aren’t always necessary. “A lot of materials out there are already well characterized. If you’re concerned about speed to market, introducing a new material typically precludes your ability to get to market very quickly,” explained Gerbec.
For the most part, efficacy studies tend to be done primarily for proof of concept. “If an OEM can prove a device is safe to use but it doesn’t perform the therapy that it’s intended to, then there’s really no point in bringing it to market,” Langenderfer said.
But efficacy studies aren’t just for implants. Often they are performed on instrument systems as well. For these tests, simulated surgeries will be performed in cadaver specimens. “This is key because without an efficient and robust instrument system to get it into the body, it may never get used,” Gerbec said.
Testing Spinal Implants
Perhaps the fastest growing segment of the orthopedic industry is the area of spinal motion preservation devices. “Up until recently, the standard of care for many causes of lower back pain has been to fuse the joint,” Gerbec explained. “The spinal industry is now moving more and more toward motion preservation.” As this market grows, companies that test implants or make testing equipment have to add a number of testing processes to their cadre of services.
A large number of ASTM test standards are used to characterize a wide variety of implants including fusion and motion preservation devices. Gerber noted that these may include static tests, which measure the static strength, or cyclic tests, which measure the extended life of a product under repeated loads. He added that new testing standards currently are being developed so that a variety of motion preservation devices can be adequately compared to one another.
A critical test for new spinal motion preservation devices is wear testing, which characterizes the debris that will be generated by articulating components. “Artificial discs and even some of the dynamic stabilization systems have articulating members, so you have to conduct wear tests to identify the volume of wear debris you are generating and also to characterize that debris to see what particle sizes you’re generating,” Gerbec explained.
NAMSA’s Carraway agreed. “With artificial joints going into the spine, there’s a concern over wear debris being generated,” he said. “Those particles get picked up by some of the macrophages, but they can also stimulate loosening of the joint where it attaches to the bone.”
He added that the FDA tends to be more concerned about the wear of artificial discs than it is with hips and knees. “A revision surgery for a hip or knee joint does not have the same degree of risk as a revision on the spine, so the FDA is much more cautious,” he said.
Other Tests
Along with efficacy studies and tests for spine technology, a variety of other analytic tools are being used in orthopedics.
One area of growth in the testing industry is the analysis of surface coatings. One of NAMSA’s orthopedic clients is looking at different surface coatings to enhance bone integration into that surface and improve bone attachment.
“The hydroxy appetite spray coating is the current gold standard coating for these types of implants, but it’s also a fairly expensive and labor-intensive process. So this OEM is looking at some other options,” explained Carraway. For these studies, simulated devices will be made using different coatings. They are then placed in a bone to see how well the bone attaches to the devices compared to the gold standard. “Depending on the nature of that treatment and what it does to the finished device, the company will determine if they need to go into any safety testing as well,” Carraway added. “They’ll come up with the version that they think will be useful to them before they go down the road of safety testing.”
Particulate testing is another important test used to ensure that large particles aren’t left on the device after manufacture. “We use two methods for particulate testing,” explained Brandon Tillman, sales representative for Nelson Labs, based in Salt Lake City, UT. “One is light obscuration, which is an automated particulate count. The other is a microscopic method.” The microscopic method tends to be used more often for medical devices, while pharmaceutical products usually require the more stringent light obscuration method.
Nelson Labs provides a variety of other services including sterilization validation, package testing, biocompatibility testing, and reusable device studies—one of the company’s fastest growing services. “It appears that more pressure is being put on manufacturers that sell their devices to hospitals to validate their instructions for use,” Tillman added.
Incision Tech’s Walden also has seen growth in the demand for these tests. “Many OEM device manufacturers are looking for ways to educate their customers and their customers’ potential patients about the negative aspects of either reusing or using reconditioned devices that were originally designed for single-use or for multiple-use in a single procedure,” Walden said. “For devices with a cutting or piercing function, this issue is especially important due to the degradation of the sharp edges on the cutting components of single-use surgical devices.”
His company has provided lab and testing services for at least one OEM device customer to analyze cutting edges of surgical devices after single use and after reconditioning. “In both cases, the cutting edges of surgical devices designed for single use that have been cleaned and sterilized for re-use or that had been reconditioned showed significant degradation of the cutting edge, which can mean degraded performance during subsequent use in the operating room,” Walden explained. “Manufacturers can use the results of such studies to help educate their customers.”
More Growth Ahead
As orthopedic manufacturers learn more about specific issues pertaining to their devices, they are focusing on different aspects of the testing process. “For example, knee replacements are continuing to evolve, so manufacturers need to figure out how much of the soft-tissue restraint should remain versus how many stops to actually build into the device,” Johnson explained. “We, as a testing equipment manufacturer, try to lead with some of these tools but also sometimes follow the demands of the industry.”
With all of the effort being put into orthopedic product development and the innovative, complex devices being designed, the importance of testing and analysis will continue to grow. By incorporating testing at the earliest possible stages of development, orthopedic manufacturers can fine tune their designs more quickly, resulting in reduced manufacturing costs, decreased development times as well as safer, more reliable products.