For decades, Class III medical devices that are implanted in humans, such as hip implants, have been approved by the FDA through the 510(k) process. The 510(k) process is the fast-track approval process, which does not require clinical studies or pre-market testing. This process was never intended for Class III medical devices; however, a loophole in the FDA regulations that was never addressed until recently has allowed thousands of implanted medical devices to be approved without clinical testing.

As a result of this process, hundreds of thousands of metal-on-metal (MoM) hip implants have been sold and implanted in patients without any premarket clinical testing. The changes to the design of these implants have proven to be defective over the years, and as a result, patients with these implants have suffered from cobalt and chromium poisoning and severe tissue and bone damage. Many of these patients have also required a revision surgery to remove the defective device.

The U.S. Food and Drug Administration has attempted to close this loophole as it applies to these MoM implants and, as a result, it may leave future patients who suffer from these devastating damages with no legal recourse.

The FDA Loophole for Medical Devices

The FDA has had regulatory authority over medical devices since the passage of the Medical Device Amendments (MDA) in 1976. The MDA created three classes of devices: Class I, low-risk devices; Class II, moderate-risk devices; and Class III, high-risk devices. The classes roughly correspond with the level of FDA premarketing approval that is required. Class I and II devices, such as toothbrushes, latex gloves and infusion pumps, were meant to undergo review for substantial equivalence to devices already on the market for approval. Class III devices, such as orthopedic implants, were meant to go through the more rigorous premarket approval (PMA), which requires evidence of clinical data. However, a loophole allowed Class III devices to receive market clearance through substantial equivalence temporarily until the FDA down-classified these devices or promulgated regulations requiring PMA. It was always Congress’ intent to have Class III devices go through PMA. In 1990, Congress directed the agency to establish a schedule to finish the transition to require PMA for all devices that are to remain at Class III. However, 19 different devices, including MoM hip implants, are currently permitted to reach patients through the 510(k) fast-track process.

This loophole has permitted the manufacturers of hip implants to market MoM implants without establishing safety and effectiveness through clinical testing. Instead, they are able to merely claim substantial equivalence to an earlier predicate device or pieces of that device, which often times was also found substantially equivalent to an earlier predicate device and so on. Many of these devices were never determined to be safe and effective. In fact, when you trace the ancestry of these devices back through all the predicate devices, they often go back to devices that have never been determined to be safe and effective. 

Legal Impact of Proposed FDA Order

In response to the recent epidemic concerning MoM hip implants, on January 18, the FDA proposed an order that would require MoM hip implants to go through full premarket approval, thereby requiring clinical data. According to the proposed order, any manufacturer who wishes to continue to market a MoM hip implant, even if it was previously cleared through the 510(k) process, will be required to submit a PMA or a notice of completion of a product development protocol (PDP) within 90 days of the publication of the final order. If a PMA or notice of a PDP is not filed with the FDA for a device that is currently on the market, the device will be considered adulterated.

The legal implications of this order will mean immunity for manufacturers of MoM hips. Any previously marketed or new MoM hip implant that goes through PMA will have immunity under the U.S. Supreme Court decision in Riegel v. Medtronic, 552 U.S. 312 (2008). In 2008, the Supreme Court ruled that manufacturers of certain medical devices approved by the FDA’s premarket approval process are immune from liability, even when the devices are known to be defective.

The issue in the case was the meaning of the pre-emption clause contained in the MDA. The MDA contains an express pre-emption clause, 21 USC § 360k, that displaces any state law “requirement” that “relates to the safety or effectiveness” of a medical device and is “different from, or in addition to, any [federal] requirement.” In Riegel, the court determined that common law tort liability constituted a “requirement” under the MDA and common law tort claims were expressly preempted by the MDA’s statutory language.

The Riegel court reasoned that the PMA medical device was subject to an intense FDA approval process resulting in detailed federal requirements relating to design, manufacturer and labeling and that a successful state tort lawsuit would effectively impose further and competing design, manufacturer and labeling requirements on the manufacturers. Under Riegel, both design defect and inadequate warning claims are pre-empted for any medical device that goes through the PMA process. However, there is no pre-emption for medical devices that receive 510(k) clearance because that process does not entail a determination by the FDA that the device is safe and effective and it does not have the same rigorous requirements as the PMA process. 

Pros and Cons of the Order


  •  More rigorous pre-market approval standards for MoM hip implants. The proposed order will provide assurances that all MoM implants on the market will have gone through clinical testing and meet the more rigorous approval standards under PMA. This will also put into place stricter requirements for the design, manufacture and labeling of these devices. As a result, the MoM implants on the market will be much safer than the currently marketed MoM implants.
  •  Current devices that do not meet the more rigorous standard will be taken off the market. The order requires clinical testing for any MoM implants that intend to stay on the market. Thus, any devices that fail to perform clinically will be removed from the market. This will save thousands of potential recipients from being implanted with a defective device in the future.
  •  Recognition of inadequate premarket testing for all MoM hip implants. The proposed order supports the thousands of claims that have been brought by injured recipients asserting that the mechanical testing performed on these devices is inadequate. The FDA recognizes that the wear testing performed underestimates the metal wear when compared to clinical outcomes. The FDA’s criticism regarding the lack of standardization coupled with unpredictable trends essentially questions the adequacy of mechanical testing performed on any medical device, not just hip implants.


  •  Many other Class III medical devices are still not required to undergo clinical testing. This order is specifically limited to MoM hip implants. There are many other Class III medical devices that are still permitted to obtain market clearance without clinically testing. Even other hip implants will still be permitted to go through the fast-track 510(k) approval process. In order to ensure the safety and effectiveness of all Class III medical devices, the FDA still has a lot of work to do.
  •  Many manufacturers of MoM hip implants will be able to avoid product recalls. Since the recall of the DePuy ASR MoM implant in 2010, the performance of many MoM implants has been called into question. The proposed order will allow many manufacturers of MoM implants to effectively escape from recalling their products. As an alternative, under the order, the manufacturers can choose to take the product off the market by deciding not to undergo the expense and time of clinical trials.
  •  Future patients harmed by a defective MoM implant will have no legal recourse. After full effect of the proposed order is in place, and all MoM implants have either been approved under the PMA process or taken off the market, any future patients harmed by a defective MoM implant will not be permitted to bring a lawsuit under Riegel. In essence, the effect of the proposed order will provide immunity to the manufacturers of MoM implants because they will fall under the pre-emption clause of the MDA. 

Melissa Fry Hague is an associate at Anapol Schwartz in Philadelphia who has dedicated her career to the successful and diligent prosecution of mass torts with a focus on defective medical devices. She can be reached at 215-790-4563 or