Mounting trouble with artificial hips

A national joint registry could enable doctors to know with certainty that they were matching the right type of prosthesis to the appropriate patient because they could sort data based on patient characteristics. They could then assess product life and revision rates for their type of patient. Regulatory agencies such as the FDA could move quickly when problems arose. And it would cover not just artificial hips, but knees and other joints too.

Medical device makers argue that a voluntary product registry is the right approach. The American Academy of Orthopedic Surgeons has given seed money to launch a nonprofit, the American Joint Replacement Registry.

The voluntary registry's executive director said the goal is to create the largest registry in the world, one similar to Australia's mandatory system. But the project has been thwarted by the lack of a uniform method for hospitals to scan data, such as a bar code. Instead, hospitals must assign a staff person to enter data. In 18 months, 116 hospitals have agreed to participate. The group hopes to attract more than 3,000. In addition, device makers need to develop a plan for adding serial numbers to actual devices without increasing risk of corrosion or metal exposure.

"Everybody says, 'Why haven't we done this in the past?' But really technology is just being brought up to speed where we can do it," said registry Executive Director Jeffrey Knezovich.

Recent prosthetic hip recalls

The FDA encourages patients who have metal-on-metal hip replacements to follow up with their surgeons and seek regular blood tests.

2008: Zimmer Durom Acetabular Component ("Durom Cup") label recall, because of surgical technique instruction issues. On the market with updated instructions, but, according to a company spokesman, no longer for sale in the United States due to lack of demand.

2010: DePuy ASR Total Hip System, because of higher-than-anticipated revision rates according to non-U.S. joint registries. Off the market.

2012: Stryker Rejuvenate and ABGII modular neck-stems because of corrosion. Off the market.

2012: DePuy Orthopaedics unused custom hip and knee replacement implants; a warning letter from the FDA said that they had not been properly approved for use in patients, DePuy disagreed. Off the market.

Source: FDA/DePuy/Zimmer

Alerted late

The problems with Stryker's Rejuvenate and ABGII modular hip joints were revealed first not in the U.S., where at least 20,000 were implanted over almost three years, but in Australia, where far fewer were implanted. Australia picked up the problems first because of its national joint replacement registry.

sunday@tribune.com