A 57-year-old female underwent total ankle arthroplasty for post-traumatic arthrosis using the Agility Total Ankle System. The talar component was placed in varus malalignment. Her postoperative course was remarkable for 19 months of satisfactory function followed by the acute onset of intense pain and decreased range of motion. There was no history of trauma. After failing a short course of observation, revision surgery of the arthroplasty was performed. Operative findings revealed a complete fracture of the polyethylene. This report details the first case of such a complication and discusses the importance of component alignment in the prevention of polyethylene insert failure.