Sam Brusco, Associate Editor09.20.16
Device testing providers have quite a challenging job. Rather than focusing their efforts on a specific set of devices or components as an OEM or supplier might, they have to be the “jack-of-all-trades” of the medical device world, knowledgeable about any type of device to employ their respective testing methodologies. They must be able to adapt to technological progress more rapidly than most, lest their test strategies become outdated and delay or halt a device’s market launch—or worse, result in recalls or disciplinary action against an OEM.
The orthopedic device industry contributes even more hoops to jump through for device manufacturers and testing service providers alike. Orthopedic devices are among the first in medtech to experiment with newer materials and manufacturing methods. It almost need not be mentioned that the continued rise of additive manufacturing has impacted orthopedic device manufacturing, challenging testing service providers to devise appropriate methods to test the material properties specific to the new manufacturing process. In the same vein, “orthobiologics”—devices that use tissue, cell, or gene-based therapies in conjunction with hardware—require altered testing methodologies to account for the presence of materials that may degrade when subjected to typical tests.
Before digging into the trends in orthopedic device testing specifically, it is important to examine the trends of orthopedic devices in general. If select technologies or methods to manufacture them proliferate, it logically follows that certain types of testing required for those devices will also be in high demand.
Dr. Daniel Prince, president of Fairfield, N.J.-based Gibraltar Laboratories, described the landscape of current orthopedic technology as he sees it. “With technology like robotics, custom implants, and 3D printing/additive manufacturing, products are becoming more affordable and customizable,” he said. “Minimally invasive techniques are gaining acceptance in orthopedics and other areas of surgery. In turn, the medical device industry is developing products tailored to what's needed for minimally invasive procedures. Also popular are more detailed instructions for use (IFU) and modifications in design for reprocessing of the devices.”
Rudy Pina, lab director of El Paso, Texas-based Dynatec Labs, noticed a similar trend among orthopedic technologies. “3D printing (referred to as additive manufacturing) is being used to develop prototypes for various devices such as hip, spinal, and knee applications,” he said.
Pina also noted collaboration at the university level for device development, though, in a limited capacity: “According to the Keck Institute, at the University of Texas at El Paso, prototypes are being developed for OEMs, for research and development only. However, this is only for the Keck Institute, which is developing a variety of devices, the majority of which are designed using titanium.”
As far as the testing protocols that service providers are seeing more of as a result of technological trends, Gary Socola, president of Rochester, N.Y.-based HIGHPOWER Validation Testing & Lab Services Inc., said, “We are noting a trend where medical device manufacturers (MDMs) are trying to streamline the IFU of their family of products into a single IFU that contains the same cleaning and sterilization parameters to be used with multiple devices. We have worked on several projects where the MDMs have streamlined their device IFUs for thousands of devices, and when the project is completed, the MDM is left with just a handful of IFUs that will cover the complete line and family of their devices. This is a tremendous help for healthcare workers in the Central Sterile department.”
“We see a shift into a risk-based approach to evaluate biocompatibility,” remarked Thor Rollins, consulting manager for Salt Lake City, Utah-based Nelson Laboratories. “Orthopedics use very common materials and processing, and based on that, many companies are using synergies with previously approved devices to evaluate biological risk and keep repeat biological testing to a minimum. Chemistry is a useful tool in these comparisons.”
Despite common materials and processing, however, the orthopedic technologies that are in high demand reflect the increasingly personalized approach to healthcare delivery. As such, testing methodologies must get creative and equipment more flexible to account for patient-specific devices that don’t quite have a traditional testing approach.
“With personalized solutions, the size of the device may change. Therefore, it’s necessary to design for the extremes of size,” explained Jennifer Brookes, Ph.D., project manager and thermal expert for Christiansburg, Va.-based Polymer Solutions. “This means that mechanical testing may be even more important for personalized devices.
Seek to avoid a device that works well in some instances but not in others; there will likely be a greater demand for product testing to mimic the actual use of the product. In addition, the robustness portion of validation should be even more important than normal for additive manufacturing, where customization becomes the norm.”
“Custom implants and personalized medical devices are ideal products for a Computer Aided Inspection (CAI) process that utilizes the computer aided design (CAD) model as the ultimate reference file,” suggested Bill Greene, CEO and vice president of partnership development for Stuart, Fla.-based Level 3 Inspection. “Since all modern products—and certainly all custom implants—are made from a CAD model and that is used as the primary reference, it is easy to compare and inspect anything that is needed, including any feature or dimension from the derived drawing.”
Additive Manufacturing Also Adds Testing Complexity
Additive manufacturing (known in layman’s terms as 3D printing) has become a buzzword in the context of orthopedic device manufacturing. It fits in quite nicely with orthopedic (and medical in general) technology’s journey toward the patient-specific, due to the ability to use patient scans as a basis for device design and manufacture. Although it has been on the circuit for several years now, the technology is still new enough that testing service providers don’t quite have a specific arsenal of tests in place.
“Additive manufacturing introduces novel concerns from a testing perspective, inherent to both the advantages of 3D printing and the details of the fabrication process,” said Matthew R. Jorgenson, Ph.D., chemistry and materials scientist for Nelson Laboratories. “One of the key advantages of additively manufactured devices is that they can be made to precisely fit the patient’s unique biometric information, obtained from clinical measurements. The testing complication there is that each device is different, and establishing a meaningful reference, such as a cleaning coupon, for such a moving target can be challenging. Generally, orthopedic devices use additive manufacturing that relies on the laser heating and fusion of powdered raw materials. In this case, the final material itself is formed during the manufacturing process, and since the reactions resulting in the final material can proceed inhomogenously across the fabrication platform, the final result may be a material that is, itself, inhomogenous. Addressing this is a concern unique to additively manufactured devices, and is addressed in the recent FDA draft guidance document on this same topic.”
Jorgenson is referring to the set of standards the U.S. Food and Drug Administration (FDA) drafted in May 2016 (to address the startling growth of additively manufactured devices), which were guidelines to give manufacturers an idea of how to best navigate compliance. “Technical Considerations for Additive Manufactured Devices” did its best to address everything from R&D to device labeling, with an entire section devoted to device testing. It seems to provide fairly comprehensive guidelines for device description, mechanical testing, dimensional measurements, material characterization, cleaning and sterilization, and biocompatibility—however, the question remains of how adequately it addresses orthopedic device testing.
“The guidance document gives a nice high level overview of the considerations that must be taken when producing an orthopedic device,” said Jason Smith, a chemist for Polymer Solutions. “However, being a guidance document, it is not going to be very specific to any particular application. The document notes the potential difficulty of rendering a properly fitted device based on a digital image, the potential need to alter the device once it has been printed, and makes a nice separation between stock shapes and patient-specific devices. It will be interesting to see how testing of 3D printed orthopedic devices develops, as most of these devices will likely be patient-specific and many of them will likely be load bearing. One concern is how to predict or determine the strength of a load-bearing device if it is not a standard shape.”
While Jorgenson believes “the FDA’s recent draft guidance on 3D-printed medical devices is a positive step forward to understanding 3D-printed devices, their potential risks, and how to best approach addressing those risks from a biocompatibility viewpoint,” he also expressed that there is definitely room for improvement.
“While the section on materials characterization emphasizes development of a deeper understanding of the chemistry underlying the final material to assess biocompatibility, this goal—while noble—may be unrealistic,” he added. “This is due to the complexity of the reactions taking place during the additive manufacturing process and potential interactions with sacrificial materials. Extractable testing per ISO 10993-18 to measure and assess substances leaving the device allows potential toxicity to be addressed, while not requiring prediction or precise determination of the formulation of the final device material.”
But not everyone agrees that the document adequately outlines testing methodology, or that it provides an apt starting point; some assert that for a true set of guidelines, some heavy revision is in order. “FDA does not adequately address the issue related to testing,” said Prince. “It just mentions that it should be similar to the non-additive manufactured products.”
Putting Service Providers to the Test
The challenges associated with orthopedic device testing are manifold. Advanced materials and manufacturing methods, the increasing miniaturization of technologies, and incorporation of biologics and “combination devices” that include both hardware and pharmaceuticals are causing service providers to evaluate their testing methods alongside the devices they test.
Pina outlined the effects certain types of orthopedic device design have on testing methods, stating, “Test protocols—biocompatibility, for instance—will require changes when the device is designed with unique considerations such as increased porosity, complex pathways, and/or tissue-based designs.”
Biocompatibility stands out as possibly the most important and challenging among orthopedic device tests, simply because the device will spend most of its life on or in the body. Testing service providers make sure to pay especially close attention to potential obstacles in this area of evaluation.
“For biocompatibility testing, the device size is one of the biggest challenges,” noted Rollins. “When a device is very small or extremely large, it makes it difficult to test, especially if that device is metallic where it’s not easily cut. In these cases, we tend to help develop ‘coupon’ devices. These are representative devices that serve as the material composition and processing of the actual device, but bigger or smaller.”
The materials used to manufacture orthopedic devices range from traditional metals, like titanium, and porous materials to biologic components. As such, some devices may contain a combination of these materials, which changes the testing strategy significantly. Testing service providers must have a set plan in place for evaluation of these potentially tricky multi-material technologies.
“For different materials, different test methods may apply. For example, with a polymer, you may be concerned about loss of molar mass over time, but that same parameter will not apply to a metal,” explained Brookes. “Because of the unique requirements of materials, it’s important to make sure you understand the material itself and the methods that may apply. Expertise to correctly test and interpret the results is also crucial.”
“The AAMI standards have different sterilization cycles listed for loads containing porous or non-porous devices,” stated Socola. “Therefore, a test plan is built for the device—for example, cleaning and sterilization efficacy—based on whether the device itself is porous or non-porous. Also, some materials cannot withstand the high temperatures produced in steam autoclaves. Therefore, we work directly with device manufacturers, or sometimes with their material vendors, in order to develop and validate a low temperature sterilization process, such as hydrogen peroxide or ethylene oxide (EtO). We have two fully programmable EtO units in our lab and six hydrogen peroxide sterilizers from multiple manufacturers available for this purpose.”
“Testing protocols can be different for an orthobiologic device as compared to an orthopedic device,” Prince pointed out. “For example, a different process is used to neutralize the antibiotics present on a collagen implant. As a result, it takes more time to neutralize the antibiotics contained in collagen implants, as compared to orthopedic devices with an antibiotic coating.”
Despite the bit of gymnastics testing service providers must sometimes perform to account for all of these complexities, sometimes the most effective method lies in the application of advanced inspection technology.
“For our CAI dimensional inspection systems, it doesn't matter what the material of construction, surface finish, or size of the part might be,” Greene asserted. “Since we are specialized in comprehensive and high-precision manufacturing with tight tolerances, and capable of measuring to accuracies of ±2 microns (±0.000078"), the material or manufacturing method doesn't matter for our 3D scanning or analysis for measuring.”
Learning from Failure
Despite their best efforts, orthopedic device manufacturers are sometimes met with failed tests. The reasons for failure can be myriad, and testing service providers have seen them all. However, it’s not just enough to tell an orthopedic device manufacturer that their device has failed and send them back to the drawing board. A testing provider wholeheartedly seeking the most productive outcome for a manufacturer will also provide guidance for the test’s retake, or else refer them to someone who can.
“The biggest culprit that we see with orthopedic device test failures is trying to put too many complex devices or devices with a substantial amount of mass in the same orthopedic tray or set,” explained Socola. “On paper, it may make sense to try and incorporate everything that a surgeon needs into a single set, but if that set can’t be effectively cleaned or sterilized following the typical parameters used in healthcare, much time, money, and effort needs to be extended to revalidate another set when the first one fails. OEMs would do themselves a service by having a microbiologist or employee trained in proper device cleaning/sterilization procedures to be involved earlier in the design process.”
“Most of the failures we see are either from certain metals (i.e., copper, silver, zinc) or uncured adhesives. We also see failures due to residuals from the manufacturing processes. These could include oils or detergents left on the device,” noted Rollins. “In either case, we perform an investigation to determine the source of the failure and then try to eliminate it, or we perform chemistry to determine the residual amount and perform a safety assessment to determine clinical impact from the residual.”
Greene said the unique demands of the orthopedic device industry can leave manufacturers’ practices obsolete enough to fail a device test. “We have found that a substantial amount of orthopedic device failures are due to relying on archaic dimensional inspection methods that do not provide adequate insight, understanding, or confidence in making fast decisions to meet today's industry needs,” he told Orthopedic Design & Technology. “The main benefit of having 10,000-times more information with which to make process optimization decisions is speed with confidence. This is exceptionally valuable in today’s competitive marketplace.”
No solution to a failed test is a simple one, but testing service providers, more than most, collaborate with manufacturers to determine precisely what the error was and how to remedy it. “Sometimes the design of the tray or load configuration needs to be optimized,” Prince pointed out. “In other cases, the instructions for use are incorrect or too vague. We help OEMs to revise IFU and/or optimize the tray systems.”
Studying for Future Tests
Device testing service providers must be more vigilant than manufacturers about future trends. If an OEM is using a novel material or manufacturing method, the testing strategy for that material or method can’t lag too far behind, or it will be inadequate to effectively evaluate the device. So what do those with an especially weathered eye on the horizon anticipate in the coming years?
“I’d expect there to be more and more customized mechanical testing that’s scalable to the size of the device,” predicted Brookes. “Additive manufacturing opens up a new area where different materials that aren’t currently used for these applications might be useful. That may require additional biocompatibility testing, as well as studies related to extractables and leachables from these compounds.”
“There is a focus by the FDA on industry to provide clearer and more detailed IFUs, as was the case for the reprocessing of endoscopes,” observed Prince. “With these new IFUs, more testing requirements may be required in the near future to assure compliance and patient safety.”
“In the future, physical challenges for various metals, such as titanium, may require a whole new set of test methods and associated equipment—devices are usually tested in-vitro, and therefore size issues will create a need for appropriate test equipment such as test vessels, manipulators, and various unique glassware,” envisioned Pina.
Greene continued to hammer home the importance of incorporating the latest technology into testing services. “As faster process optimization and increased throughput with conformance to ever-tightening requirements become the drivers of the industry in the new market requirements, CAI services and systems are becoming recognized as the fastest and best way to achieve these objectives,” he concluded. “The CAI benefits quickly become evident—working with full 3D surface information, presented in much easier to understand ways, for faster, better, more confident decision support.”
“It is our hope that in the near future, the medical device industry will have a short list of standardized device cleaning cycles which MDMs can comply to,” said Socola. “These cleaning cycles would be a start for MDMs and the FDA during validation testing and would be similar to the typical sterilization cycle that are currently listed in the AAMI ST-79 standard. This may create a bit of turbulence for companies submitting new 510(k) device submissions, as they may be asked by the FDA to comply with a specific set of cleaning parameters, rather than use what has been in their IFU currently for other devices.”
The orthopedic device industry contributes even more hoops to jump through for device manufacturers and testing service providers alike. Orthopedic devices are among the first in medtech to experiment with newer materials and manufacturing methods. It almost need not be mentioned that the continued rise of additive manufacturing has impacted orthopedic device manufacturing, challenging testing service providers to devise appropriate methods to test the material properties specific to the new manufacturing process. In the same vein, “orthobiologics”—devices that use tissue, cell, or gene-based therapies in conjunction with hardware—require altered testing methodologies to account for the presence of materials that may degrade when subjected to typical tests.
Before digging into the trends in orthopedic device testing specifically, it is important to examine the trends of orthopedic devices in general. If select technologies or methods to manufacture them proliferate, it logically follows that certain types of testing required for those devices will also be in high demand.
Dr. Daniel Prince, president of Fairfield, N.J.-based Gibraltar Laboratories, described the landscape of current orthopedic technology as he sees it. “With technology like robotics, custom implants, and 3D printing/additive manufacturing, products are becoming more affordable and customizable,” he said. “Minimally invasive techniques are gaining acceptance in orthopedics and other areas of surgery. In turn, the medical device industry is developing products tailored to what's needed for minimally invasive procedures. Also popular are more detailed instructions for use (IFU) and modifications in design for reprocessing of the devices.”
Rudy Pina, lab director of El Paso, Texas-based Dynatec Labs, noticed a similar trend among orthopedic technologies. “3D printing (referred to as additive manufacturing) is being used to develop prototypes for various devices such as hip, spinal, and knee applications,” he said.
Pina also noted collaboration at the university level for device development, though, in a limited capacity: “According to the Keck Institute, at the University of Texas at El Paso, prototypes are being developed for OEMs, for research and development only. However, this is only for the Keck Institute, which is developing a variety of devices, the majority of which are designed using titanium.”
As far as the testing protocols that service providers are seeing more of as a result of technological trends, Gary Socola, president of Rochester, N.Y.-based HIGHPOWER Validation Testing & Lab Services Inc., said, “We are noting a trend where medical device manufacturers (MDMs) are trying to streamline the IFU of their family of products into a single IFU that contains the same cleaning and sterilization parameters to be used with multiple devices. We have worked on several projects where the MDMs have streamlined their device IFUs for thousands of devices, and when the project is completed, the MDM is left with just a handful of IFUs that will cover the complete line and family of their devices. This is a tremendous help for healthcare workers in the Central Sterile department.”
“We see a shift into a risk-based approach to evaluate biocompatibility,” remarked Thor Rollins, consulting manager for Salt Lake City, Utah-based Nelson Laboratories. “Orthopedics use very common materials and processing, and based on that, many companies are using synergies with previously approved devices to evaluate biological risk and keep repeat biological testing to a minimum. Chemistry is a useful tool in these comparisons.”
Despite common materials and processing, however, the orthopedic technologies that are in high demand reflect the increasingly personalized approach to healthcare delivery. As such, testing methodologies must get creative and equipment more flexible to account for patient-specific devices that don’t quite have a traditional testing approach.
“With personalized solutions, the size of the device may change. Therefore, it’s necessary to design for the extremes of size,” explained Jennifer Brookes, Ph.D., project manager and thermal expert for Christiansburg, Va.-based Polymer Solutions. “This means that mechanical testing may be even more important for personalized devices.
Seek to avoid a device that works well in some instances but not in others; there will likely be a greater demand for product testing to mimic the actual use of the product. In addition, the robustness portion of validation should be even more important than normal for additive manufacturing, where customization becomes the norm.”
“Custom implants and personalized medical devices are ideal products for a Computer Aided Inspection (CAI) process that utilizes the computer aided design (CAD) model as the ultimate reference file,” suggested Bill Greene, CEO and vice president of partnership development for Stuart, Fla.-based Level 3 Inspection. “Since all modern products—and certainly all custom implants—are made from a CAD model and that is used as the primary reference, it is easy to compare and inspect anything that is needed, including any feature or dimension from the derived drawing.”
Additive Manufacturing Also Adds Testing Complexity
Additive manufacturing (known in layman’s terms as 3D printing) has become a buzzword in the context of orthopedic device manufacturing. It fits in quite nicely with orthopedic (and medical in general) technology’s journey toward the patient-specific, due to the ability to use patient scans as a basis for device design and manufacture. Although it has been on the circuit for several years now, the technology is still new enough that testing service providers don’t quite have a specific arsenal of tests in place.
“Additive manufacturing introduces novel concerns from a testing perspective, inherent to both the advantages of 3D printing and the details of the fabrication process,” said Matthew R. Jorgenson, Ph.D., chemistry and materials scientist for Nelson Laboratories. “One of the key advantages of additively manufactured devices is that they can be made to precisely fit the patient’s unique biometric information, obtained from clinical measurements. The testing complication there is that each device is different, and establishing a meaningful reference, such as a cleaning coupon, for such a moving target can be challenging. Generally, orthopedic devices use additive manufacturing that relies on the laser heating and fusion of powdered raw materials. In this case, the final material itself is formed during the manufacturing process, and since the reactions resulting in the final material can proceed inhomogenously across the fabrication platform, the final result may be a material that is, itself, inhomogenous. Addressing this is a concern unique to additively manufactured devices, and is addressed in the recent FDA draft guidance document on this same topic.”
Jorgenson is referring to the set of standards the U.S. Food and Drug Administration (FDA) drafted in May 2016 (to address the startling growth of additively manufactured devices), which were guidelines to give manufacturers an idea of how to best navigate compliance. “Technical Considerations for Additive Manufactured Devices” did its best to address everything from R&D to device labeling, with an entire section devoted to device testing. It seems to provide fairly comprehensive guidelines for device description, mechanical testing, dimensional measurements, material characterization, cleaning and sterilization, and biocompatibility—however, the question remains of how adequately it addresses orthopedic device testing.
“The guidance document gives a nice high level overview of the considerations that must be taken when producing an orthopedic device,” said Jason Smith, a chemist for Polymer Solutions. “However, being a guidance document, it is not going to be very specific to any particular application. The document notes the potential difficulty of rendering a properly fitted device based on a digital image, the potential need to alter the device once it has been printed, and makes a nice separation between stock shapes and patient-specific devices. It will be interesting to see how testing of 3D printed orthopedic devices develops, as most of these devices will likely be patient-specific and many of them will likely be load bearing. One concern is how to predict or determine the strength of a load-bearing device if it is not a standard shape.”
While Jorgenson believes “the FDA’s recent draft guidance on 3D-printed medical devices is a positive step forward to understanding 3D-printed devices, their potential risks, and how to best approach addressing those risks from a biocompatibility viewpoint,” he also expressed that there is definitely room for improvement.
“While the section on materials characterization emphasizes development of a deeper understanding of the chemistry underlying the final material to assess biocompatibility, this goal—while noble—may be unrealistic,” he added. “This is due to the complexity of the reactions taking place during the additive manufacturing process and potential interactions with sacrificial materials. Extractable testing per ISO 10993-18 to measure and assess substances leaving the device allows potential toxicity to be addressed, while not requiring prediction or precise determination of the formulation of the final device material.”
But not everyone agrees that the document adequately outlines testing methodology, or that it provides an apt starting point; some assert that for a true set of guidelines, some heavy revision is in order. “FDA does not adequately address the issue related to testing,” said Prince. “It just mentions that it should be similar to the non-additive manufactured products.”
Putting Service Providers to the Test
The challenges associated with orthopedic device testing are manifold. Advanced materials and manufacturing methods, the increasing miniaturization of technologies, and incorporation of biologics and “combination devices” that include both hardware and pharmaceuticals are causing service providers to evaluate their testing methods alongside the devices they test.
Pina outlined the effects certain types of orthopedic device design have on testing methods, stating, “Test protocols—biocompatibility, for instance—will require changes when the device is designed with unique considerations such as increased porosity, complex pathways, and/or tissue-based designs.”
Biocompatibility stands out as possibly the most important and challenging among orthopedic device tests, simply because the device will spend most of its life on or in the body. Testing service providers make sure to pay especially close attention to potential obstacles in this area of evaluation.
“For biocompatibility testing, the device size is one of the biggest challenges,” noted Rollins. “When a device is very small or extremely large, it makes it difficult to test, especially if that device is metallic where it’s not easily cut. In these cases, we tend to help develop ‘coupon’ devices. These are representative devices that serve as the material composition and processing of the actual device, but bigger or smaller.”
The materials used to manufacture orthopedic devices range from traditional metals, like titanium, and porous materials to biologic components. As such, some devices may contain a combination of these materials, which changes the testing strategy significantly. Testing service providers must have a set plan in place for evaluation of these potentially tricky multi-material technologies.
“For different materials, different test methods may apply. For example, with a polymer, you may be concerned about loss of molar mass over time, but that same parameter will not apply to a metal,” explained Brookes. “Because of the unique requirements of materials, it’s important to make sure you understand the material itself and the methods that may apply. Expertise to correctly test and interpret the results is also crucial.”
“The AAMI standards have different sterilization cycles listed for loads containing porous or non-porous devices,” stated Socola. “Therefore, a test plan is built for the device—for example, cleaning and sterilization efficacy—based on whether the device itself is porous or non-porous. Also, some materials cannot withstand the high temperatures produced in steam autoclaves. Therefore, we work directly with device manufacturers, or sometimes with their material vendors, in order to develop and validate a low temperature sterilization process, such as hydrogen peroxide or ethylene oxide (EtO). We have two fully programmable EtO units in our lab and six hydrogen peroxide sterilizers from multiple manufacturers available for this purpose.”
“Testing protocols can be different for an orthobiologic device as compared to an orthopedic device,” Prince pointed out. “For example, a different process is used to neutralize the antibiotics present on a collagen implant. As a result, it takes more time to neutralize the antibiotics contained in collagen implants, as compared to orthopedic devices with an antibiotic coating.”
Despite the bit of gymnastics testing service providers must sometimes perform to account for all of these complexities, sometimes the most effective method lies in the application of advanced inspection technology.
“For our CAI dimensional inspection systems, it doesn't matter what the material of construction, surface finish, or size of the part might be,” Greene asserted. “Since we are specialized in comprehensive and high-precision manufacturing with tight tolerances, and capable of measuring to accuracies of ±2 microns (±0.000078"), the material or manufacturing method doesn't matter for our 3D scanning or analysis for measuring.”
Learning from Failure
Despite their best efforts, orthopedic device manufacturers are sometimes met with failed tests. The reasons for failure can be myriad, and testing service providers have seen them all. However, it’s not just enough to tell an orthopedic device manufacturer that their device has failed and send them back to the drawing board. A testing provider wholeheartedly seeking the most productive outcome for a manufacturer will also provide guidance for the test’s retake, or else refer them to someone who can.
“The biggest culprit that we see with orthopedic device test failures is trying to put too many complex devices or devices with a substantial amount of mass in the same orthopedic tray or set,” explained Socola. “On paper, it may make sense to try and incorporate everything that a surgeon needs into a single set, but if that set can’t be effectively cleaned or sterilized following the typical parameters used in healthcare, much time, money, and effort needs to be extended to revalidate another set when the first one fails. OEMs would do themselves a service by having a microbiologist or employee trained in proper device cleaning/sterilization procedures to be involved earlier in the design process.”
“Most of the failures we see are either from certain metals (i.e., copper, silver, zinc) or uncured adhesives. We also see failures due to residuals from the manufacturing processes. These could include oils or detergents left on the device,” noted Rollins. “In either case, we perform an investigation to determine the source of the failure and then try to eliminate it, or we perform chemistry to determine the residual amount and perform a safety assessment to determine clinical impact from the residual.”
Greene said the unique demands of the orthopedic device industry can leave manufacturers’ practices obsolete enough to fail a device test. “We have found that a substantial amount of orthopedic device failures are due to relying on archaic dimensional inspection methods that do not provide adequate insight, understanding, or confidence in making fast decisions to meet today's industry needs,” he told Orthopedic Design & Technology. “The main benefit of having 10,000-times more information with which to make process optimization decisions is speed with confidence. This is exceptionally valuable in today’s competitive marketplace.”
No solution to a failed test is a simple one, but testing service providers, more than most, collaborate with manufacturers to determine precisely what the error was and how to remedy it. “Sometimes the design of the tray or load configuration needs to be optimized,” Prince pointed out. “In other cases, the instructions for use are incorrect or too vague. We help OEMs to revise IFU and/or optimize the tray systems.”
Studying for Future Tests
Device testing service providers must be more vigilant than manufacturers about future trends. If an OEM is using a novel material or manufacturing method, the testing strategy for that material or method can’t lag too far behind, or it will be inadequate to effectively evaluate the device. So what do those with an especially weathered eye on the horizon anticipate in the coming years?
“I’d expect there to be more and more customized mechanical testing that’s scalable to the size of the device,” predicted Brookes. “Additive manufacturing opens up a new area where different materials that aren’t currently used for these applications might be useful. That may require additional biocompatibility testing, as well as studies related to extractables and leachables from these compounds.”
“There is a focus by the FDA on industry to provide clearer and more detailed IFUs, as was the case for the reprocessing of endoscopes,” observed Prince. “With these new IFUs, more testing requirements may be required in the near future to assure compliance and patient safety.”
“In the future, physical challenges for various metals, such as titanium, may require a whole new set of test methods and associated equipment—devices are usually tested in-vitro, and therefore size issues will create a need for appropriate test equipment such as test vessels, manipulators, and various unique glassware,” envisioned Pina.
Greene continued to hammer home the importance of incorporating the latest technology into testing services. “As faster process optimization and increased throughput with conformance to ever-tightening requirements become the drivers of the industry in the new market requirements, CAI services and systems are becoming recognized as the fastest and best way to achieve these objectives,” he concluded. “The CAI benefits quickly become evident—working with full 3D surface information, presented in much easier to understand ways, for faster, better, more confident decision support.”
“It is our hope that in the near future, the medical device industry will have a short list of standardized device cleaning cycles which MDMs can comply to,” said Socola. “These cleaning cycles would be a start for MDMs and the FDA during validation testing and would be similar to the typical sterilization cycle that are currently listed in the AAMI ST-79 standard. This may create a bit of turbulence for companies submitting new 510(k) device submissions, as they may be asked by the FDA to comply with a specific set of cleaning parameters, rather than use what has been in their IFU currently for other devices.”