DePuy Hip Implants Medical Malpractice

An instance of medical malpractice does not necessarily have to involve a doctor or surgeon acting negligently and making a mistake or misdiagnosing something. Sometimes, the malpractice goes far deeper, and is rooted in defective products and other medical equipment that doctors and surgeons use and count on to fix your health problem. When a medical device is defective or does not perform as it is supposed to, your injury can fall in both a products liability issue, as well as a medical malpractice issue.

DePuy's hip implants are an excellent example of this happening in real life. These metal parts that were used in hip replacements have proven to be defective in numerous ways – an unsurprising development, considering how quickly they were approved by the government. Worse, DePuy tried covering up the problems, putting even more innocent patients at risk until they were forced to make a recall.

The lawyers at the Maryland law firm Gilman & Bedigian handle both types of cases, representing clients who have been seriously hurt by defective medical devices in Maryland, Washington, D.C., and Philadelphia.

How Hip Replacements Work

When people need a hip replacement – often due to excessive arthritis pain or from some serious hip fractures, or when their hip mobility is severely impinged by some other factor – they need to undergo a surgery that removes all or most of the hip joint and replaces it with a prosthetic implant, or hip prosthesis. These surgeries are the most common orthopedic procedures in America, and either remove both the acetabulum portion of the pelvis and the femoral head of the femur in a total hip arthroplasty procedure or just the femoral head in a hemiarthroplasty procedure.

There are three prosthetic pieces that are implanted to replace these bones. To replace the femur's femoral head, surgeons drill a hole in the top of the femur bone closest to the hip, aiming deep down towards the knee. A stem of metal is then inserted into this drilled hole in the femur. At the exposed tip of this metal stem is an acetabular cup, often made of metal or other hard substance, like ceramic or polyethylene. This cup extends inside the concave of the pelvis, where it is held in place as a ball-and-socket joint. This joint is either screwed or cemented in place on the inside of the patient's pelvis.

However, there can be differences in each one of these prosthetic pieces. For example, the acetabular cup at the end of the femoral head that fits into the ball-and-socket joint can come in a variety of different substances, each with strengths and weaknesses. Additionally, these cups can be made of one piece or two. These factors determine exactly how the ball-and-socket joint is optimally affixed inside the patient's pelvis.

Despite being immensely common, these procedures often cost more than $40,000 in the United States.

DePuy Synthes and Hip Prosthetics

One of the companies that make these hip prosthetics is DePuy Synthes.

DePuy has been in the business of making medical devices since 1895. However, it was bought out by the pharmaceutical company Johnson & Johnson in 1998 for $3.5 billion. DePuy has since been operating in the U.S. and internationally as one of the many divisions of the conglomerate in its Medical Devices branch. Many of DePuy's devices, moreover, are sold under different brand names, such as Codman, and through subsidiaries like DePuy Orthopaedics, Inc. and DePuy Spine, Inc.

It is the subsidiary DePuy Orthopaedics, Inc. that makes the hip prosthetics that are used in many of the hip replacement surgeries in the U.S. and across the world, including the ones that have been the subject of extensive legal action taken by innocent medical malpractice victims.

DePuy ASR XL Acetabular Systems

DePuy's hip prosthetics come in a variety of different models. These models use different designs that span a wide spectrum in pricing and offer a number of different levels of mobility and durability. Some models can even be implanted in far less invasive surgeries than others.

Starting in 2005, DePuy started offering a new kind of hip implant: The DePuy ASR XL Acetabular System. The “ASR” was the trademark designation for the particular kind of single-piece socket that the device used, while the “XL” highlighted how the device could be made larger than other models that were currently on the market. Because it included both the femoral head stem and the socket joint for the pelvis, and so replaced portions of the pelvis in addition to putting a prosthetic at the end of the femur bone, the ASR XL device could only be used for full hip replacements – total hip arthroplasties, not hemiarthroplasty procedures.

ASR XL Hip Implants and the FDA Approval Process

Like all implantable medical devices, there was an extensive testing and approval process by the Food and Drug Administration (FDA) for DePuy's ASR XL hip implant. As a Class III implantable device that presented the potential for an unreasonable risk to health, the FDA. The rigor of the FDA's testing, however, depends on when the product was set to be released: Class III devices released before May 28, 1976 – the date of the FDA's Medical Device Amendments – are not as closely tested as those released after that date.

However, there is a loophole in the law. If a medical device is released after the enactment of the FDA's Medical Device Amendments – so-called “postamendment devices” – but is deemed to be “substantially equivalent” to a “preamendment device,” then the postamendment device is treated as if it were released before that magical date. This lets the device to be sold without the regular battery of clinical trials and testing that many surgical equipments, and especially implantable prosthetics, should get before being used on living people.

Being “substantially equivalent” to an older implant required DePuy to show that its ASR XL hip implant had the same intended use as the older device, and either

  1. The same technological characteristics as the older device, or
  2. Had different technological characteristics, but the information submitted to the FDA from the new device's manufacturer showed both that it did not raise new safety or effectiveness concerns, and demonstrated that the new device was at least as safe and effective as the old one.

Wanting to avoid the tedious testing and approval process and get their new ARS XL implant out into the market and start making them money, DePuy applied for and received a “substantial equivalence” exception to the process. According to a report that was published in a report that was published in the New England Journal of Medicine, though, to get this classification for their ARS XL implant, DePuy claimed that their new device was “substantially equivalent” to prior, “preamendment” hip implants in three important ways:

  1. It used a porous bone ingrowth surface,
  2. It utilized metal-on-metal articulation, and
  3. The femoral head sizes it used were large, between 57 and 63 millimeters.

Importantly, though, the ARS XL was not equivalent to any of the earlier models listed in DePuy's application in more than one way. Instead, the equivalence application that DePuy submitted to streamline the FDA approval process claimed that the new device was similar to old versions of hip implants in certain characteristics, but not in others.

DePuy's application strained that their new ARS XL model had a metal-on-metal articulation that was “substantially equivalent” to three implantable hip prosthetics that were used before the magic date in 1976: The McKee-Farrar Hip System, the Ring Hip System, and the Sivash Hip System, all of which had proven to need so many revisionary surgeries that they had all stopped being used.

In addition to having a metal-on-metal articulation, the ARS XL also involved femoral headpieces that were larger than normal. The preamendment hip implants that DePuy claimed were “substantially equivalent” to their ARS XL model, however, had never been used in total hip replacements. They had only been used for partial hip replacements.

Finally, the porous ingrown surface that the ARS XL model relied on, and which DePuy claimed was “substantially equivalent” to preamendment hip implants, was not used in metal-on-metal articulation implants in the earlier models.

Therefore, none of the older hip implant devices used all of the characteristics that DePuy was claiming were “substantially equivalent” to its newer ARS XL model. Nevertheless, the FDA approved DePuy's application and the ARS XL was given the fast track in to the market.

Complications with DePuy's ASR XL Hip Implants

Without adequate testing and clinical trials by the FDA, it should come as no surprise that DePuy's ARS XL hip implant prosthetic was fraught with problems from the start.

Typically, hip replacement prosthetics fail to do their jobs between 0.5% and 3% of the time. However, the ARS XL prosthetic was quickly found to be failing at a rate of 13%. This required more than one out of every eight patients to return to the hospital to get a “revision surgery” because the prosthetic was either loosening, breaking, or repeatedly dislocating, wearing too quickly, or because of an infection. The problem was so bad that DePuy recalled the ARS XL model in August, 2010. However, New York Times investigation found that DePuy likely knew of the poor results long before then, but had covered them up to preserve its profit.

One of the reasons for such a high failure rate was the metal-on-metal design that the ARS XL used. This design, it was soon discovered, created other problems, as well.

As metal rubs on metal – something that happens naturally in ball-and-socket joints – tiny shards of metal come off from the friction. Despite the lubricant that was used in the ARS XL joints, the poor construction of the implant caused increased wear and tear. Every day, this caused tiny pieces of metal to come off from the device in far greater quantities that with other metal-on-metal hip implants. Because these metallic bits came from an implant, there was only one place for them to go: Into the patient's bloodstream.

Patients who have had DePuy's ARS XL Acetabular System implanted during a hip replacement and who have had subsequent blood tests have shown high levels of heavy metals in their bloodstream: Their levels of cobalt were 39 times higher than normal, and their levels of chromium were 28 times higher. This made them hypersensitive to metals and frequently leads to increased chances of contracting cancer.

It also leads to another serious medical condition, metallosis, which is the concentration of metal fragments in soft tissues. While medical research is still not certain of the details, metallosis seems to involve the body's immune system attacking the invading metal pieces, creating an autoimmune response that ends up impacting those soft tissues that the metal fragments have clung to inside the body. This can often result in necrosis, as the immune system weakens and kills the soft tissue in its attempt to protect the body against the metal fragments from the hip implant. Unfortunately, this often weakens the tissue that holds the implant in place, causing pain and more friction between the metal parts, leading to even more metal being eroded off and into the bloodstream.

Maryland Medical Malpractice Attorneys at Gilman & Bedigian

DePuy's hip implants were rushed through the FDA approval process entirely too quickly, and these clear design problems were not found until the prosthetics were being surgically placed into living people's bodies. By then, it was too late. Nevertheless, DePuy had opportunities to do the right thing and recall their implants before too much damage had been done, or at least stop doctors and surgeons from recommending them and using them in procedures. However, they focused on their profits instead of the people they were hurting.

If you or a loved one has had a DePuy ARS XL Acetabular System implanted during a hip replacement, getting legal help is crucial. You deserve compensation, and DePuy deserves to pay it. Contact the medical malpractice attorneys at the Maryland law office of Gilman & Bedigian. Call us at (800) 529-6162 or contact us online for a free consultation.

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