Balancing innovation and medical device regulation: the case of modern metal-on-metal hip replacements

Abstract

Due to problems with wear particle generation and subsequent loosening using conventional metal-on-polyethylene total hip replacements, there has been a shift toward alternative bearing systems, including metal-on-metal (MoM), for younger, more active patients with degenerative joint disease. Based on positive results from early short-term clinical studies, MoM hip replacements were readily adopted by orthopedic surgeons with thousands being implanted worldwide over the past decade. Unacceptably high revision rates reported by two national joint registries called into question the rigorousness of the regulatory approval process for these implants, particularly with respect to premarket data requirements to prove safety, effectiveness, and the appropriateness of the regulatory pathway chosen. The purpose of this review was to investigate the balance between facilitating the introduction of new medical technologies and the need to ensure safety and effectiveness through comprehensive regulatory assessment. The case of MoM hip replacement devices was used to frame the investigation and subsequent discussions. The regulatory approval processes and post-market surveillance requirements associated with three common MoM hip replacements (two resurfacings: the Birmingham and articular surface replacement and the articular surface replacement XL total hip replacement) were investigated. With respect to modern MoM hip replacement devices, the balance between facilitating the introduction of these new medical technologies and the need to ensure safety and effectiveness through comprehensive regulatory assessment was not achieved. The lessons learned from these experiences have application beyond joint replacements to the introduction of new medical technologies in general, particularly for those who have a significant potential for harm. In this regard, a series of recommendations have been developed to contribute to the evolution of the medical device regulatory process.

Impact of regulations on innovation in the field of medical devices

“…National regulations agencies are critical to the innovation and competitiveness in the medical device sector. These agencies are the gatekeepers ( Figure 2) who decide which products are effective and safe enough to enter the market (Curfman and Redberg, 2011;Gollaher and Goodall, 2011;Howard, 2016;Krucoff et al, 2012).…”

The new U.S. FDA regulations on biocompatibility and reprocessing for medical devices

“…Namely, none of the animals that were implanted with the metal-on-metal hip implants showed any health problems or weight loss. Also, the clinical studies on human subjects were too short to show the eventual wearing down of the hip implants [105]. Although the hip implants were safe when newly implanted, the unforeseen problems occurred only when the hip implants were inserted into actual patients, and the metal parts began to grind against each other for several years [106].…”

An Overview of Food and Drug Administration Medical Device Legislation and Interplay with Current Medical Practices

“…Class I devices are deemed low-risk and are unlikely to cause bodily harm if a malfunction occurs [2]. They are regulated by general (i.e., assurance of safety and effectiveness) controls which are deemed sufficient to maintain safety to the public [3]. Rigorous data-driven FDA approval is not needed for Class I devices, however, if post-marketing surveillance shows a device to be unsafe the FDA is able to remove it from the market.…”

“…Class II devices are deemed moderate-risk devices and are unlikely to lead to preposterous bodily harm if a malfunction occurs [2]. They are not only regulated by general controls but additionally special (i.e., requirements for special labeling, performance marketing, and post-market surveillance) controls [3]. Most devices which fall into this category obtain FDA clearance by the premarket notification 510(k) process prior to the device entering the market.…”

“…The 510(k) process has recently been controversial and attracted much media attention. It has critically been reviewed where some have deemed it flawed and unreliable [3]. Examples of Class II devices include cardiac monitors, tampons, surgical drapes, and foreign body retrievers [2].…”