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Medical devices in the spotlight.

Many older adults rely on hip or knee replacements to relieve the pain and discomfort of osteoarthritis. Improving the design of implants can help achieve these objectives--but as we touch on in one of this month's cover articles, new technologies often are marketed without sufficient high quality evidence for improved benefit over existing, well proven, and safe alternatives. The recent review we reference in our article raises questions about the regulatory oversight of medical devices here in the U.S.

Artificial hips and knees have to be approved by the Food and Drug Administration (FDA) before they can be legally marketed. Under the FDA's approval system, these devices are considered to be "class HY--meaning that they present a high level of risk to patients. In view of this, you would imagine that class HI devices have to undergo extensive clinical and safety evaluations before being approved--and the FDA does have a system in place for ensuring this. It's called premarket approval (PMA), and in the case of artificial hips it includes rigorous mechanical endurance and stress tests. It is lengthy and costly for both the device manufacturer and the FDA--a PMA application costs in the region of $240,000 for manufacturers, and it costs the FDA about $870,000 to process the application.

However, there is a "shortcut" that manufacturers can take instead. Known as premarket notification--or the 510(k) approval process--it essentially "pre-approves" products that are similar to another device that is already approved for sale, enabling manufacturers to bypass expensive clinical trials. Under 510(k) it also is possible for products to be approved on the basis of being substantially equivalent to products that are themselves substantially equivalent to other products (called "grandfathering."). This means it is possible for the devices at each link in the chain to have avoided rigorous clinical trials prior to being marketed.

This method of approval is significantly less costly than PMA--manufacturers pay $4,348 and it costs the FDA about $18,200 to process the application. However, it is important to keep in mind that cost isn't the only reason for truncating the approval process. The 501(k) approach is intended to make medical devices that may benefit your health and wellbeing available in a timely, cost-effective manner. It also takes into account the fact that many devices are used by a relatively small number of patients, meaning that large premarket clinical trials may not be feasible.

Products that are insufficiently vetted prior to and after marketing can cause potentially serious complications--such as the higher revision rates seen with some of the implants evaluated in the review. However, for most people undergoing joint replacement, the procedure continues to be safe and effective. If you are scheduled for joint replacement, ask your surgeon the reasons why he or she recommends a specific implant so that you can make an informed choice.

By Rosanne M. Leipzig, MD, PhD Editor-in-Chief

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Author:Leipzig, Rosanne M.
Publication:Focus on Healthy Aging
Date:Jan 1, 2015
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