Professionalism/Metal-on-Metal Hip Implants

Introduction

Metal-on-metal (MoM) hip implants are a class of hip implant which feature both a metal cup and a metal head in their design. Initially thought to be more durable than their predecessors, MoM implants were quickly found to pose health risks to their recipients. While individual doctors notified MoM hip implant producers of their flaws, companies often ignored these notices in favor of profits. The policies of regulatory agencies such as the FDA were initially lenient enough to allow their continued sales, and only after several years were these policies adjusted to ensure that all MoM hip implants on the market explicitly met safety standards. The professional ethics of individuals, companies, and regulatory agencies are all highlighted by the case of MoM hip implants and demonstrate how participant groups can exacerbate or mitigate faulty product consequences.

Background

Hip replacements

The hip joint in the human body experiences extensive use throughout its lifetime. Due to general wear and tear, injuries, or medical predispositions, the cartilage between the femur and hip socket can wear away. This causes inflammation, pain, stiffness, and difficulty walking. Noninvasive treatments such as physical therapy, steroid injections, and anti-inflammatory or arthritic medications are applied first. When the problem does not respond to these methods, more invasive treatments are required. Hip replacements are an option for patients. There exists multiple types of manufactured hip implants:

• Metal-on-Polyethylene (MoP)
• Metal-on-Metal (MoM)
• Ceramic-on-Polyethylene (CoP)
• Ceramic-on-Ceramic (CoC)
• Ceramic-on-Metal (CoM)

Doctors have access to a variety of implant materials and devices to tailor to each patients' needs.

Proposed benefits of MoM implants

MoM hip implants were originally marketed towards younger osteoarthritic patients. These implants were expected to last longer than previously utilized materials and allow for a greater range of motion to the patient. This would enable injured patients to return to their high levels of activity in pastimes or sports. Many people received these types of implants due to the perceived benefits soon after the devices entered onto the market. But, doctors and patients were unaware of the problems these devices would cause down the road.

Unforeseen (or ignored) future implant complications

Many MoM implants were faulty or caused adverse health affects in patients. This included both short term and long term detriments. Due to the recurring problems with these devices, over 570 hip replacement recalls occurred from 2003 to 2013. A number of implant manufacturers had recalls for their devices, but DePuy and Stryker had the highest number with 150 and 231, respectively. Below are several reasons MoM implants were recalled, but are not limited to:

• Manufacturing
• Packaging
• Design flaws
• Early failures
• Instructions
• Missing parts

These problems persisted throughout the use of this implant and caused stress for both patients and doctors. Doctors could often not properly implant the devices into patients and would have to perform multiple revision surgeries.

Long-term health effects of faulty MoM hip implants

Faulty MoM implants can release toxic levels of metal ions into the bloodstream, causing metallosis. Symptoms of metallosis include:

• Tissue, bone, and nerve damage
• Pain and swelling
• Heart problems
• Visual impairment
• Tinnitus/deafness
• Cognitive impairment

Treatment typically requires one or more revision surgeries to remove or replace the faulty implant, putting patients at risk for further complications during surgery.

FDA orthopedic device approval process

In the early 2000s, orthopedic devices like hip implants could be cleared by the FDA for sale in the United States through a process called premarket notification. This process requires manufacturers to notify the FDA of their intention to sell a new device 90 days before it is released. The premarket notification process does not require manufacturers to submit clinical data. Instead, manufacturers must show that the new device is substantially similar to a "predicate device" that is already on the market. Following multiple controversies, including MoM hip recalls, the FDA has taken steps to eliminate the use of premarket notification for Class III medical devices.

Involved participants

The depth of this case created involvement from a number of parties. The patients with faulty or dangerous MoM implants were the ones most directly affected by manufacturers' wrongdoings. The physicians played an integral role as the participants implanting the problematic devices into their patients. They also served as medical experts when sharing their experiences and knowledge with the manufacturers, legal representatives of the patients, and the FDA. Due to large and numerous settlements between patients and orthopaedic manufacturers, legal representatives were heavily involved. The manufacturers themselves were involved parties for their marketing, producing, and selling of the faulty devices. Finally, the FDA became a major player during the tail end of this controversy with their review and removal of MoM implants from the market.

The Case of DePuy Orthopedics ASR Hip Implant

DePuy Orthopedics developed the ASR hip resurfacing and ASR XL hip replacement devices in response to competition with Smith & Nephew, another orthopedics manufacturer. The ASR and ASR XL devices both used MoM construction. The ASR hip resurfacing device was never cleared for use in the United States but saw international use beginning in 2003. The ASR XL hip replacement device was cleared for use in the United States in 2005 by FDA premarket notification. Between 2003 and 2010 more than 93,000 ASR and ASR XL devices were implanted in patients worldwide, including 30,000 ASR XL implants in the United States. In 2010, data from the National Joint Registry of England indicated that the five-year failure rates of ASR and ASR XL implants were 12% and 13%, respectively—much higher than the average for other hip implants. Citing this data, Depuy issued a voluntary recall of the ASR and ASR XL products on August 24, 2010. Since the recall, DePuy has faced over 10,000 lawsuits resulting in over $4 billion in settlements.

Many of the lawsuits against DePuy allege that the company was aware of problems with the ASR family of devices but continued to market them anyway. Documents released in the lawsuits include emails from surgeons noting concern about the products. A December 2008 email from Dr. William Griffin to DePuy's head of marketing, Paul Berman, urged the company not to market it while postmarket clinical data was studied. Another surgeon, Dr. Thomas Sampson, filed a complaint with DePuy in December 2008 stating "We have abandoned the use of the ASR cup … I have never had so many patients have early failure and it has affected my reputation." Internal company emails released in the lawsuits also indicated that DePuy was aware of problems with ASR. In April 2008, DePuy researcher Dr. Graham Isaac received clinical data showing high levels of metal ions in ASR patients. In an email to DePuy executives, he stated "I believe that this data will appear in the journals … and has the potential to seriously affect our business." Paul Berman, DePuy's head of marketing, reacted to Isaac's email stating "We will ultimately need a cup redesign but the short term action is manage perceptions." In a March 2009 email to DePuy management, the VP of marketing Raphael Pascaud stated:

Launching products in Australia is an issue – because of the way the registry does measure effectiveness. This should not preclude us from launching there but on the contrary should push us to put in place much more robust clinical evaluation protocols, early user groups, … Unfortunately, we are continuously discarding this need by reducing our clinical spend and still launching products with minimum clinical experience.

Conclusions and Larger Context

The circumstances surrounding metal-on-metal hip implants demonstrate how professionalism can be upheld or neglected by participants at all levels. Drs. William Griffin and Thomas Sampson followed their professional values by reporting faulty hip implants and personally preventing their further implementation. Unlike the cases of Dan Applegate and other individuals who expressed concerns about their work's reliability, Drs. Griffin and Sampson had the unilateral authority to cease the distribution of a faulty product. Their professional use of this power prevented further harm from MoM hip implants.

Meanwhile, companies like DePuy failed their professional duties by developing and selling demonstrably faulty products to patients. Competition with Smith & Nephew motivated the rushed development of a MoM hip implant, and as with other engineering groups, cutting corners made their product unsafe. In this case, competition between companies did not motivate innovation or improvement because competition was centered around profit rather than product quality.

Regulatory groups such as the FDA adjusted their policies after alarming MoM safety data was published, but their actions were slow and reactive, resulting in consequences which could have been avoided with preemptive action. Unlike previous rulings by the FDA which prevented harmful medical products' use in the United States, the FDA's lack of foresight in this case allowed thousands of patients to be harmed.

MoM hip implants demonstrate how professionalism can be expressed by individuals, companies, and regulatory agencies. While further work is required to understand all the major contributors to MoM hip implant usage, as well as how widespread these motivations are among medical products, it is clear that deviating from high-quality, patient-focused products and policies can lead to severe medical consequences.