Synovial Metallosis After Ceramic Total Ankle Arthroplasty Treated With a Total Talar Prosthesis: A Case Report

Total ankle arthroplasty is a useful surgical procedure for osteoarthritis of the ankle, but aseptic loosening of components is an issue. We report here a case of aseptic implant loosening with metallosis after total ankle arthroplasty using the TNK ankle (Kyocera, Kyoto, Japan), which occurred despite the components being ceramic. We also report favorable results from our method of treatment using a total talar prosthesis in the revision surgery. During the revision surgery, synovial metallosis was found, probably related to superficial damage to the screw affixing the tibial component to the bone. Because both the tibial and talar components were loose, all the components and the remaining talar bone were removed. A new tibial component and a custom-made alumina-ceramic total talar prosthesis was inserted. Pain relief was achieved and maintained through the latest follow-up visit at 42 months after revision surgery. Dorsiflexion of the ankle improved from 0 degrees to 5 degrees and plantarflexion remained unchanged from its preoperative range of 20 degrees. The American Orthopaedic Foot & Ankle Society ankle-hindfoot score improved from 38 to 80 points. To the best of our knowledge, this is the first reported case of an aluminaceramic total ankle prosthesis loosening caused by metallosis resulting from screw abrasion. Favorable treatment results were obtained by using a total talar prosthesis in the revision surgery. (C) 2019 by the American College of Foot and Ankle Surgeons. All rights reserved.