Patient Receives World’s First All-Plastic Ankle Implant

A 71-year-old patient with a lifelong allergy to metal has undergone the world’s first all-plastic total ankle replacement surgery. The procedure was successfully performed at MedStar Georgetown University Hospital in Washington, DC.

X-rays showed that Margaret “Meghan” Lembesis of Washington Grove, MD, had little to no cartilage remaining in her right foot. Over time, this made walking extremely difficult. Because of her metal allergy, few options were available to treat her condition.

Metal has been used in these procedures since ankle replacement technology was first developed in the 1970s. Initial implants had poor results, and it wasn’t until the early 1990s that FDA approved an ankle replacement system.

Few, if any, other options for patients with metal allergies

“A patient with severe documented sensitivities to a variety of metals would have few, if any, options [to an all-plastic implant],” said  Paul Cooper, MD, foot and ankle orthopedic specialist at MedStar Georgetown University Hospital who performed the surgery on Lembesis. “Even ankle fusion, an alternative to replacement at the expense of eliminating ankle joint motion, would not be possible without the use of some form of metal to achieve a successful outcome. The plastic ankle offers pain relief while preserving joint mobility, which the vast majority of patients currently prefer over fusion.”

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A strong, lightweight polymer

The ankle replacement used by Cooper to treat Lembesis is made from polyetherketoneketone (PEKK), a strong, lightweight thermoplastic initially developed for aerospace applications. PEKK has numerous advantages in medical applications, according to a news release from MedStar, including being trimable, antibacterial, shapable, and MRI friendly. It has been successfully applied for more than 10 years for partial skull replacement, spine, and other fusions in the body, added the healthcare provider.