Regulators in the U.K. have issued a safety warning for the Ankle Evolution System (AES), a system used in total ankle replacement system. According to the Medicines and Healthcare (MHRA) Products Regulatory Agency, a review of the scientific literature by the British Orthopaedic Foot & Ankle Society has indicated patients implanted with AES components display a higher than expected frequency of osteolytic lesions.
According to the MHRA, Transysteme, the French company that manufactures the AES total ankle replacement system, has recalled all lots of the device. Ostyeolytic lesions are a consequence of osteolysis, a reaction that occurs when the body is exposed to foreign material. In osteolysis, the bone becomes soft and gradually disintegrates. Osteolysis can lead to failure of the joint and destruction of the bones around the ankle, sometimes to the point that amputation of the lower leg is necessary. Osteolysis often has no symptoms, and is often only detected on an x-ray.
The AES total ankle replacement system was manufactured by Transysteme SA, but marketed by Biomet. The device consists of a polyethylene floating bearing situated between two metal components made of a cobalt/chromium alloy. Since 2009, reports have linked these components to a high rate of osteolysis, with some research indicating that as many as 50% of AES could develop the condition.
The MHRA is recommending that doctors in the U.K. identify patients with the AES total ankle replacement system. Patients should be followed-up with annually, and doctors should consider:
- CT scan if patients present with increasing pain or if X-rays show evidence of lesions
- More frequent follow up for patients presenting with minor asymptomatic lesions
- Surgical intervention for symptomatic or larger/multiple lesions