FDA issues warning over Exactech shoulder implants at risk of oxidation

FDA issues warning over Exactech shoulder implants at risk of oxidation

The FDA this week published a safety notice alerting patients and healthcare providers to possible risks linked to certain shoulder joint replacement implants.

The Equinoxe Shoulder System, which is sold by Exactech, is used to replace shoulder joints that are causing pain or have lost normal structure and function due to various forms of arthritis or injuries to the area. The implants have been sold in the U.S. since 2004.

In its notice, the FDA warns that Equinoxe devices sold until August 2021 were “packaged in defective bags” that omitted a layer of material that’s meant to protect plastic components of the implants from excessive exposure to oxygen that may lead to oxidation.

If oxidation did occur while the devices were in their packaging, the plastic pieces may have started to degrade, speeding up the expected timeline for device wear and failure and potentially causing the components to crack or fracture while implanted. In those instances, patients may need to undergo another surgery to repair or replace the damaged device.

Because of those risks, the FDA is recommending that healthcare providers stop implanting any Equinoxe systems that were packaged in the defective bags and to monitor any patients who have already been implanted with devices sold between 2004 and 2021. Though the agency doesn’t recommend that currently well-functioning systems be preemptively removed or replaced, it is advising doctors to consider conducting revision surgery on patients who are experiencing worsening pain or joint weakness that may be linked to the implant.

The FDA noted in the safety alert that Exactech has “declined to initiate a voluntary recall” for the affected Equinoxe shoulder implants, but added that it is still working with the company to review information about the devices’ safety and effectiveness and to evaluate the risks of all of its implants that may have been distributed in defective packaging—since the same issue has been identified in many of Exactech’s other joint replacement devices, including those for the knee, ankle and hip, leading to voluntary recalls in 2021 and 2022.

The regulator also said it’s working with its international counterparts to dig into registry data concerning the affected shoulder implants to “explore potential causes of the higher failure rates.”

Exactech, meanwhile, defended its decision to hold off on a formal recall of the Equinoxe implants in a “general advisory notice” published on its website. In it, the company described how revision surgeries are typically rarer among shoulder replacements than those for the hips, knees and ankles, since shoulders generally bear far less weight than the other joints, therefore putting less stress on the implants.

Exactech also cited registry data collected in the U.K. and Australia showing that, across both countries and both anatomic total shoulder (aTSA) and reverse total shoulder (rTSA) cases, revision rates for the Equinoxe devices were largely consistent with all-cause revision rates for all shoulder joint replacement systems in both countries—except in aTSA cases in Australia, in which the Equinoxe devices were associated with a heightened risk of revision after 1.5 years.

Additional post-market study data collected by Exactech claim that among more than 4,000 aTSA Equinoxe patients in the U.S. and Europe, only 18 experienced “some notation of polyethylene wear, osteolysis, or massive bone loss” between late 2004 and last July, adding up to an occurrence rate of 0.41%. Among more than 11,000 rTSA patients, meanwhile, the rate fell to 0.07%, with just eight reported occurrences.

The company also tapped an independent lab to perform oxidation testing of the defective bags. The lab concluded that, after the devices’ listed five-year shelf life, those packaged in the bags registered a maximum oxidation index of 0.7, which is below the 1.0 threshold linked to negative mechanical impacts, per Exactech.

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