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Orthopedic device companies ask three questions before bringing a product to market: Will it perform as intended? Will it be profitable? Will it beat competitors’ products to the table?
These issues related to quality, cost and efficiency are difficult to gauge with physical prototyping, clinical trials and expensive lab experiments. Traditional testing is important for quality assurance, but it can significantly impact the cost and efficiency of product development.
Computational modeling and simulation (CM&S) — virtual tests that optimize the performance of devices before physical prototyping — address these issues by streamlining the R&D efforts of orthopedic companies. FDA’s recent report also shows that the agency supports the practice.
It’s clear that CM&S is poised to have a widespread impact on device design and verification as more orthopedic device manufacturers adopt the practice.
Reducing the Testing Burden
CM&S has been successful in the automotive and aerospace industries by limiting physical material testing and improving the performance and safety of finished products. The orthopedic industry has taken note, and companies increasingly rely on the approach to develop new implants.
“Modeling and simulation predict how products will work in practice,” said Victor Kosmopoulos, Ph.D., Director of Simulation for System Insight Engineering (SIE). “You assess design elements much faster than in a lab, so products are developed more efficiently.”
CM&S allows product developers to assess how orthopedic devices behave in specific clinical environments, such as in normal, osteopenic and osteoporotic bone. “That provides a significant reduction in performance risk,” Dr. Kosmopoulos said.
Engineers can also create computer models to see how implants work across various patient populations. They control and manipulate testing variables to provide a more comprehensive and accurate assessment. This contrasts with cadaveric studies, during which clinical conditions vary widely.
The fewer physical tests a company performs, the lower its (R&D) costs. Instead of running hundreds of laboratory tests, engineers make design changes to computer models and immediately assess the results.
For example, during the development of hip implants that come in six sizes, a company could test all six to determine the fatigue life of the product line. CM&S offers an alternative approach.
“Modeling can determine the worst-case implant size,” said Marc Horner, Ph.D., Distinguished Engineer at ANSYS, a company that makes simulation software. “The product development team could then perform a physical fatigue test on that one implant.”
Complementing Sources of Evidence
The orthopedic industry has relied on bench testing, animal testing and clinical trials to verify the design and performance of new technologies. These traditional testing methods have inherent strengths and weaknesses. “We’re nowhere near a place where any of these tests are going away. They’re complementary to each other,” Dr. Horner said. “There’s overlap among them in terms of the information they provide.”
CM&S complements those sources of data and provides a clearer picture of a device’s performance in a controlled environment. Engineers conduct large and exhaustive virtual experiments to understand how devices will perform under a wide range of conditions.
This approach is beneficial during the design and testing phases of a product’s life cycle, but other applications of CM&S have proven effective.
“In silico” trials address the challenges associated with performing clinical trials. Computer-generated evidence developed during these trials lets companies assess device performance and risks on large cohorts of virtual patients. For example, a company could collect clinical data on 1,000 patients, input the information into simulation software and assess how a new implant design performs in the population.
FDA has recognized the benefits of in silico trials as a way to obtain credible data on clinical device performance. “This is a burgeoning area in all of healthcare,” Dr. Horner said. “It represents the future of CM&S and how the testing could be used moving forward.”
CM&S can assess a product’s performance based on surgical technique, according to Dr. Kosmopoulos. “Simulating various surgeries allows you to conduct postoperative troubleshooting before devices hit the market,” he said. “This provides a better way to reduce the risk of product removals or revisions down the road.”
Modeling and simulation can also prove or disprove a potential safety issue. For example, the magnetic fields in MRI machines concentrate heat in the tissue surrounding orthopedic implants and could damage the devices. Dr. Horner said CM&S has been used to assess the concentration of heat in the fields and determine whether the level is below a dangerous threshold.
FDA Support Should Spark Innovation
The orthopedic industry faced a significant challenge in establishing that computational modeling was validated for regulatory decision making. In 2018, the American Society of Mechanical Engineers finalized the V&V40 Standard, a risk-based framework for establishing the credibility requirements of CM&S for products submitted to FDA for clearance.
In many cases, predicate devices served as the baseline for validating innovative products coming to market. FDA’s CM&S report outlines specifics regarding what the agency will accept as model validation for new devices.
Computation models need to be independently calibrated and validated to ensure the testing is reliable and credible, according to Dr. Kosmopoulos.
“FDA’s new guidance provides a more comprehensive look at the submission process,” Dr. Kosmopoulos said. “In prior simulations, the product developers who ran simulations defined the validations and verifications, which were subjective. Now, they must be specific.”
FDA’s new guidance defines the language used around CM&S, so that players involved in the process are on the same page with what terms mean.
Orthopedic companies can submit questions to FDA about CM&S. The agency will also review a company’s CM&S validation plan before it’s used, giving the product development team confidence in using it during device development.
FDA’s support and growing interest among orthopedic companies to use modeling and simulation suggests that the technology will evolve into a best practice for bringing new products to market effectively and efficiently, according to Dr. Horner. His best advice is to use the approach at each stage of the product life cycle.
“The sooner you model and simulate, the more value it brings to the table. You’re able to eliminate design concepts that won’t work,” he said. “You identify bad ideas early on and take them out of consideration right away.”
Dr. Horner said reducing the duration of the testing process is more important than saving on R&D. “Companies will make more money by getting products to market sooner than they would have otherwise,” he added. “Accelerating innovation is the real value statement.”
