The FDA warns that plastic components in all of Stryker’s STAR knuckles could break

The FDA today issued a warning regarding the STAR ankle previously manufactured by Stryker (NYSE: SYK) – and the possibility of the plastic component breaking.

According to an FDA press release, there is a higher than expected risk of the polyethylene (plastic) component of the device breaking as early as three to four years after the STAR (Scandinavian Total Ankle Replacement) is implanted, which can lead to surgery to repair it or to replace.

Stryker sold the STAR ankle to DJO Global in November 2020 as part of its Wright Medical acquisition.

The FDA’s analysis of post-approval studies and adverse event reports found that the risk applies to all STAR ankle devices regardless of the date of manufacture or sale.

However, the FDA noted that the implant remains suitable for certain patient populations, such as older, less active patients. Those with a more active lifestyle, osteoarthritis, or those under the age of 55 may be at a higher risk of the plastic component breaking.

The FDA said that patients considering a STAR ankle implant should discuss all treatment options for painful arthritic ankle joints with health care providers.

People with a STAR ankle implant should speak to a doctor if they experience new, worsening pain, weight loss, new grinding, or any other noise or instability in the ankle implant. A healthcare provider may need to request x-rays to assess the problem. In some cases, CT scans are used.

Based on the study, the plastic component broke eight years after implantation at a cumulative rate of 13.8% (12/87), with all fractures requiring additional surgery. Fractures were observed as early as three to four years after implantation. Stryker acknowledged previous concerns about the breakage rate, but communication on the matter excluded devices manufactured after August 1, 2014 when changes were made to the film packaging in the inner bag, which limited the material degradation of the plastic component. These changes followed a warning from the company of plastic fracture problems in the implants in 2019.

Since 2009, at least 1,841 adverse event reports have been received for the STAR ankle. The FDA concluded that 300 of the reports cited broken plastic components and included devices manufactured after the August 1, 2014 cutoff.

Stryker provided FDA data on 244 removed STAR ankle implants showing 72 fractures of plastic components. Most fractures showed degradation of material oxidation after three to four years of implantation. The FDA emphasized that this particular sample size was small.

The FDA said it is still working with Stryker to better understand the factors contributing to the problem. The two companies will work together to ensure that patients and providers are aware of the potential risk of component breakage.

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