Hintermann H3 Ankle Replacement Failures Occur in 31.8% of Patients at 10 Years, FDA Warns

Federal regulators issued a warning about Hintermann H3 ankle replacement problems early last year, after first approving the device in 2019.

Post-approval studies indicate that 10-year failure rates for the Hintermann H3 ankle replacement is more than 15 percentage points greater than initially reported, raising concerns about the risk of problems patients may experience the longer the device remains in place.

The Hintermann H3 Total Ankle Replacement (TAR) was first approved by the FDA in 2019, featuring a metal plate attached to the lower leg bone, a mobile plastic insert and a metal ankle component. It is designed to restore mobility in patients with osteoarthritis, post-traumatic arthritis or rheumatoid arthritis affecting the ankle joint.

However, in February 2024, the FDA issued a warning about Hintermann H3 Ankle Replacement failures, after post-approval studies showed that 16.1% of patients required additional surgery, such as removal or revision of metal components, compared to the 9.9% failure rate reported by the manufacturer during premarket clinical trials.

On October 31, the FDA followed up with a new safety communication, reporting that the manufacturer’s original 5- and 10-year failure estimates for the Hintermann H3 ankle replacement were substantially understated once additional surgeries involving plastic component revisions were included in the analysis, indicating that nearly 1 in 3 patients may experience problems with the first 10 years after receiving the ankle replacement.

According to this new post-approval study data, officials indicate that the total failure rates for Hintermann H3 TAR systems are 19.2% at 5-years, and 31.8% at 10-years. Prior data had listed these figures as 6.5% and 14.9% respectively. That is a greater than 12 percentage point difference at 5 years and 15 percentage points at 10 years.

The updated figures incorporate all additional surgeries involving any part of the Hintermann H3 system, including both polyethylene plastic and metal components. Failure rates were calculated using statistical analyses that measured the likelihood of component removal or revision, based on available data tracking how long it took patients in the study to require follow-up surgery.

FDA recommendations did not change as a result of these findings, with federal regulators still advising patients and caregivers to:

• Talk with healthcare providers about all available treatment options for managing arthritis-related ankle pain
• Understand that every joint replacement device and surgical procedure carries both potential benefits and risks
• Not undergo surgery to remove the ankle implant if it is working properly and no new or worsening symptoms are experienced
• Contact care providers immediately if the patient notices any new or worsening pain or swelling, difficulty walking or bearing weight, grinding or unusual noises, or weakness near the implant site
• Examine ankles and order imaging tests, such as X-rays or a CT scan, to check whether the plastic component of the Hintermann Series H3 Total Ankle Replacement system is damaged
• Report any issues or complications related to the ankle replacement system to the FDA, as these reports help improve the safety of medical devices for all patients

The Hintermann ankle implant is one of only two mobile-bearing total ankle replacement systems cleared by the FDA, the other being the Scandinavian Total Ankle Replacement (STAR) device, which received approval in 2009.

In 2021, the FDA released a comparable safety notice concerning the STAR ankle, cautioning that its plastic components were prone to breaking, which could increase the likelihood of implant failure.

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